i HABITAT MANAGEMENT FOR BENEFICIAL INSECTS IN MICHIGAN CUCURBIT AGROECOSYSTEMS By Nicole F. Quinn A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Entomology - Master of Scie nce 2015 ii ABSTRACT HABITAT MANAGEMENT FOR BENEFICIAL INSECTS IN MICHIGAN CUCURBIT AGROECOSYSTEMS By Nicole F. Quinn N atural enemies and pollinators require additional cover, habitat resources, and minimal disturbance, which are not found in conven tional agricultural fields. The purpose of this thesis was to quantify the effects of habitat management for conservation biological control and pollination in Michigan cucurbit fields and their impact s on t he arthropod community and yield. In the first s tudy , the effect s of mulch and reduced tillage on the arthropod community in acorn squash were examined. Natural enemies of weed seeds and insects were expected to be more abundant in strip - tilled, mulched plots than full - tilled, unmulched plots. Foliar ob servations did not differ among treatments . T reatment effects on ground - dwelling arthropod activity density and weed seed survival were recorded , though they varied by year. Full - tilled plots tended to have higher granivore activity densities than strip - ti lled plots. In the second study , the effect s of floral intercropping on beneficial insects and yield in a commercial cucumber field were examined. Beneficial insect abundance was expected to greater in plots containing flowers, with more beneficials found in the rows closest to the floral strips. Some floral treatments successfully attracted more beneficial insects than others, but the beneficials did not disperse out to the cucumber plants. Cucumber yi eld was generally unaffected . Habitat management for be neficial insects still holds a great deal of potential to improve yield , profitability, and sustainability, but many questions as to their application in cucurbit agroecosystems remain. iii This thesis is dedicated to my sister , Leanne, who was diagnosed with cancer during my program . Her trials have made graduate study seem easy by comparison. I look forward to enjoying many more years together. iv ACKNOWLEDGEMENTS First and foremost, I would like to thank my advisor Zsofia Szendr ei for her essential contributions to this thesis. She provided the opportunity and guidance necessary for me to develop as a researcher and has laid the groundwork for a career in entomology . My remaining committee members, Rufus Isaacs and Dan Brainard, proved to be equally invaluable sources of advice, perspective, and technical expertise. Zack Hayden and Corey Noyes also provided greatly needed assistance with the horticultural aspects of both field trials. Jason Gibbs provided assistance and resources that made bee identification for this project possible. I am indebted to Ron Goldy, Dave Francis, and the staff at the Southwest Michigan Research and Extension Center for their tireless maintenance of my field plots, constant lending of equipment, and imp re ssive patience in answering my questions. I would also like to thank my grower collaborator George McManus for allowing me to conduct research in his fields , despite the inconveniences involved . My research was made possible through grants from the USDA NIFA program (#2013 - 34103 - 21322) and USDA SARE (#GNC14 - 194) , and additional funds from the Hutson Memorial Endowment Fund and the Michigan Vegetable Council S cholarship . The legions of undergraduates who spent their summers crawling through vines and dirt and their autumns counting tiny seeds to help me collect data deserve special recognition for their hard work. I would especially like to thank Jessica Kansman for her role in data collection and helping me laugh my way through the many challenges of my fi rst field season. I would also like to thank Gabe King for his many hours spent at the microscope processing my pitfall trap samples. Although he has since moved on to bigger and better things, I would like to thank Rob Morrison for his role in the complet ion of this thesis. In addition to his scientific know - how and v a key component in its fruition . I would also like to thank John R. Winkelmann, whose mentorship during my under graduate studies inspired me to pursue field research . Last but not least, I would like to thank my family for their support. vi TABLE OF CONTENTS LIST OF TABLES ................................ ................................ ................................ ............................. viii LIST OF FIGURES ................................ ................................ ................................ ........................... ix CHAPTER 1: Habitat complexity and arthropod management in cucurbits ................................ ..... . . 1 Introduction . ................................ ................................ ................................ ........................... .. 1 Insect pests in cucurbits ................................ ................................ ............................. .. 1 Chemical contro l ................................ ................................ ................................ ........ .. 2 Natural enemies ................................ ................................ ................................ ......... .. 2 Pollinators ................................ ................................ ................................ .................. .. 4 H abitat management to en hance beneficial insect activity ................................ .................... ..5 Habitat m anagement for p ollination ................................ ................................ ...................... .. 8 Thesis o bjectives ................................ ................................ ................................ .................... 1 0 CH APTER 2: The effect of conservation tillage and cover crop residue on beneficial insects and weed seed predation in acorn squash ( Cucurbita pepo var. turbinata). ................................ ............. 12 Introduction . ................................ ................................ ................................ ........................... 12 Materials and Methods ................................ ................................ ................................ ........... 1 4 Field plots ................................ ................................ ................................ ................... 1 4 Foliar arthropod sampling ................................ ................................ .......................... 1 5 We ekly a ctivity density sampling ................................ ................................ .............. 16 Weed seed predation ................................ ................................ ................................ .. 17 R esults ................................ ................................ ................................ ................................ .... 1 8 Foliar arthropod sampling ................................ ................................ .......................... 1 8 Weekly activity density sampling ................................ ................................ .............. 19 Weed seed predation ................................ ................................ ................................ .. 2 2 Discussion ................................ ................................ ................................ .............................. 29 Overall ................................ ................................ ................................ ................................ .... 29 Foliar ar thropod sampling ................................ ................................ ........................... 3 0 Weekly a ctivity density sampling ................................ ................................ ............... 3 0 Seed predation ................................ ................................ ................................ ............. 3 1 CHAPTER 3: Integrating flower strips for beneficial insects in cucumber ( Cucumis sativus ). ........ 3 3 Introduction ................................ ................................ ................................ ............................ 3 3 Beneficial insects in agriculture ................................ ................................ ................. 34 Habitat management for pollinators ................................ ................................ ........... 3 4 Floral provisioning for beneficial insects ................................ ................................ .. 3 6 Hypotheses ................................ ................................ ................................ ................. 3 6 Materials and Methods ................................ ................................ ................................ ........... 3 7 Field plot establishment ................................ ................................ ............................. 3 7 Foliar arthropod abundance ................................ ................................ ....................... 3 8 vii Arthropod abundance on stick y trap ................................ ................................ .......... 38 Arthropod abundance by sweep net ................................ ................................ ........... 39 Pollinator observation ................................ ................................ ................................ 39 Yield ................................ ................................ ................................ ........................... 39 Statistical analysis ................................ ................................ ................................ ...... 4 0 Results ................................ ................................ ................................ ................................ .... 4 0 Foliar observation ................................ ................................ ................................ ...... 4 0 Sticky traps overall ................................ ................................ ................................ .... 4 0 Sticky trap herbivores ................................ ................................ ................................ 4 1 Sticky trap natural enemies ................................ ................................ ........................ 4 1 Sweep net overall ................................ ................................ ................................ ....... 4 6 S weep net herbivores ................................ ................................ ................................ . 4 7 Sweep net natural enemies ................................ ................................ ......................... 4 7 Sweep net pollinators ................................ ................................ ................................ . 4 8 Diversity ................................ ................................ ................................ ..................... 4 8 Pollinator observation ................................ ................................ ................................ 4 9 Yield ................................ ................................ ................................ ........................... 5 2 Discussion ................................ ................................ ................................ .............................. 5 4 Herbivores and natural enemies ................................ ................................ ................. 5 4 Pollinators . ................................ ................................ ................................ ................. 5 5 Yield ................................ ................................ ................................ ........................... 5 7 CHAPTER 4: Conclusions and Future Directions ................................ ................................ ............. 58 APPEND ICES ................................ ................................ ................................ ................................ ... 6 2 Appendix A. Supplementary data ................................ ................................ .......................... 6 3 Appendix B. Record of deposition of voucher specimens ................................ ..................... 7 5 LITERATURE CITED ................................ ................................ ................................ ...................... 7 7 viii LIST OF TABLES . Table 3.1 .......... 49 Table S.1. Major field activities in 2013 - 2015. The study took place in an acorn squash field at the Southwest Michigan Research and Extensi on Center in Benton Harbor, MI .............................. 6 3 Table S.2 . Arthopods observed on squash leaves in 2014 (a) and 2015 (b) ................................ ..... 6 4 Table S.3. Total arthro pods captured in weekly pitfall traps in 2014 (a) and 2015 (b) .................... 6 7 Table S.4. Major field activities in 2014 and 2015. The study took place in a conventionally managed cucumber field in Benton Harbor, MI. ................................ ................................ ............... 69 Table S.5. Total arthropods captured by sweep net in 2014 (a) and 2015 (b) ................................ .. 6 9 Table S.6. Total arthropods captured on sticky traps in 2014 (a) and 2015 (b). ............................... 7 2 Table S.7. Total pollinators observed in 2014 (a) and 2015 (b) ................................ ........................ 7 4 Table S.8. Voucher specimens deposited at the Albert J. Cook Arthropod Research Collection (Michigan State University). ................................ ................................ ................................ .............. 7 5 ix LIST OF F IGURES . Figure 2.1. Arthropods collected in weekly pitfall traps in the 2014 (a,b) and 2015 (c,d) growing seasons. Traps were deployed in plots that were strip - tilled or full - tilled, with no rye hay add ed (unmulched) or 0.5kg/m 2 rye hay added (mulched) ................................ ................................ .......... 2 2 Figure 2.2. Mean (±SEM) activity density of arthropods collected in weekly pitfall traps by time period in the 2014 (a,b,c,d) and 2015 (e,f,g,h) growing seasons. Traps were deployed in plots that were strip - tilled or full - tilled, with no rye hay added (unmulched) or with 0.5 m 2 rye hay added (mulched). Significant differences are indicated with different letters of the same case ( ................................ ................................ ................................ ................................ .... 2 2 Figure 2.3. Mean (±SEM) activity density of arthropods collected in seed predation pitfall traps in 2014 (a) and 2015 (b). Traps were deployed for 48 hours in plots that were strip - tilled or full - tilled, with no rye hay added (unm ulched) or 0.5kg/m 2 rye hay added (mulched). Significant ............... 2 5 Figure 2.4. Mean (±SEM) seed removal in 2014 (a) and 2015 (b). Arenas contained 100 seeds and were deploye d for 48 hours in plots that were strip - tilled or full - tilled, with no rye hay added (unmulched) or 0.5kg/m 2 rye hay added (mulched). Significant differences are indicated with ................................ ................................ 2 6 Figure 2.5. Corre lation of the activity density of Gryllidae (a) and Harpalus spp. (b) and seed removal in 2014. Data were correlated using Pearson correlation coefficients ................................ . 2 7 Figure 2.6. Correlation of the activity density of Gryllidae (a) and Harpalus spp. (b) and seed removal in 2015. Data were correlated using Pearson correlation coefficients ................................ . 2 8 Figure 3.1. Herbivore community composition as observed on 12x15cm sticky traps in the flower strips (a,b,c,d) and in cropped areas (e,f,g,h) pre and during cucumber harvest by flower treatment and location in 2015. Traps were collected and replaced weekly. ................................ ... 4 4 Figure 3.2. Natural enemy community composition as observed on 12x15cm sticky traps in the flower strips (a,b,c,d) and in cucumbers (e,f,g,h) pre and during cucumber h arvest by flower treatment and location in 2015. Traps were collected and replaced weekly. ................................ .... 4 5 Figure 3.3. Mean (±SEM) number of lady beetles (Coccinellidae) and minute pirate bugs ( Orius spp.) observed on 12x15cm sticky traps in the flower strips (Row 0) pre and during cucumber harvest by flower treatment in 2014 (a) and 2015 (b). Traps were collected and replaced weekly. Insects were identified in the laboratory. Bars with different letters of the same case are significantly different from one another ( Tu ................................ ................... 4 6 x Figure 3.4. Mean (±SEM) number of pollinators observed in cucumbers pre - harvest by treatment in 2014 (a) and 2015 (b). Observations occurred over 10 minute periods in 0.77x20m transects located within the flower strips (Row 0) and 1.5m (Row 1 ), 5m (Row 3), and 10m (Row 5) away from the flower strips, in cucumbers. Bars show averages across all distances. 0.05). Bars without letters are not signific ..................... 5 1 Figure 3.5. Mean (±SEM) number of Apis mellifera (a), Syrphidae (b), and other bees (c) observed by treatment and row in 2015. Observations occurred over 10 minute periods in 0.77x20m transects located within the flower strips (Row 0) and 1.5m (Row 1), 5m (Row 3), and 10m (Row 5) away from the flower strips, in cucumbers. Bars show averages across all distances. Bars with different letters across treatments are significantly different from one 05). Bars without letters are not significa ntly different from one another ................................ ................................ ................................ ................................ ............................ 5 2 ................................ ................................ ................................ ................................ ............ 5 3 1 CHAPTER 1 : Habitat complexity and arthropod management in cucurbits . Introduction Squashes, cucumbers, pumpkins, melons, and other gourds are domesticated members of the plant family Cucurbitaceae. There are 95 genera and over 950 species within this diverse group (Schaefer et al. 2011). Originally domesticated in pre - Colombian Mesoamerica and India approximately 10, 000 years ago, today hundreds of cucurbit varieties are grown worldwide for food, decorati on , and other purposes (Ranere et al. 2009, Zheng et. al 2013). Cucurbits are economically important crops in the United States. In 2013, 140,040 acres of pumpkins, squash and cucumber were planted, yielding over 2.5 million pounds of saleable fruit valued at over $602 million (USDA/NASS 2014). In Michigan alone, pumpkins, squash and cucumber were grown on over 45,400 acres and valued at over $43.2 million (USDA/NASS 2014). The state accounts for 37% of all U.S. acreage for these crops. Insect pests in cucurbits . Insect damage is one of the main causes of reduced yield in cucurbits. Among the most deleterious pests in Midwestern cucurbits are striped cucumber beetles ( Acalymma vittatum , Coleoptera: Chrysomelidae), spotted cucumber beetles ( Diabrotica undecimpunctata , Coleoptera: Chrysomelidae), squash bugs ( Anasa tristis , Hemiptera: Coriedae), squash vine borer ( Melittia cucurbitae , Lepidoptera: Sesiidae ) , thrips ( Fran kliniella sp., Thysanoptera: Thripidae), and two - spotted spider mites ( Tetranychus urticae , Trombidiformes: Tetranychidae). Cucurbits for the fresh market that are damaged by insects receive lower grades and may not be approved for sale (United States Stan dards for Grades of 2 Cucumbers 1997, United States Standards for Grades of Fall and Winter Type Squash and Pumpkin 1997). Herbivory in cucurbits can reduce yield by diverting energetic resources away from fruit production and towards defense (Hladun and Adl er 2009). In addition to direct damage, insects can also harm cucurbits by vectoring disease through feeding and depositing frass. For example, spotted cucumber beetles have been shown to effectively transmit bacterial wilt ( Erwinia tracheiphila ) in squash (Shapiro et al. 2014). Chemical control . Current insect management practices in cucurbit crops are highly dependent on a relatively narrow range of insecticides, which inadequately control several key pests and are cause for environmental concern. A larg e - standard insect pest management program in Michigan consists of about 8 broad - spectrum insecticide applications in any given growing season. Expenditures for insect management in these crops can easily exce ed $100 per acre for pesticide applications alone (Barnett 2012). Despite this rate of pesticide application, yield losses due to insects remain high. Fungicides are also used extensively in cucurbits, which may have negative implications for beneficial i nsects. Pollinators can be particularly vulnerable to the synergistic effects of multiple pesticide residue exposure, whether encountered directly on the plants or from spray drift (Sanchez - Bayo and Goka 2014). Natural enemies . Several parasitoids are kn own to attack squash bugs ( Worthley 1923, Olson et al. 1996). However, these parasitoids often only provide significant control after squash bug populations have increased beyond economic thresholds (Decker and Yeargan 2008). The majority of the natural en emies of cucurbit pests in the North Central region are generalist 3 predators. Important generalist natural enemies include ground - dwelling spiders (Linyphiidae, Lycosidae, Salticidae), ground beetles (Carabidae), damsel bugs (Nabidae), big - eyed bugs (Geoco ridae), and lacewing larvae (Chrysopidae) (Decker and Ye argan 2008, Snyder and Wise 2001 ). Many of these generalist natural enemies are more abundant and effective in systems that provide greater habitat complexity and reduced disturbance (Landis et al. 2 000). In zucchini, increased non - crop vegetation led to improved pest control and natural enemy abundance in cropped areas (HansPetersen et al. 2010, Hinds and Hooks 2013). Control of squash bugs by carabids and spiders was improved in cucumber and squash fields with increased structural complexity (Snyder and Wise 2008). Increasing structural complexity through mulch applications while decreasing disturbance through the use of conservation tillage may improve biological control in cucurbit fields. General ists such as ground beetles (Carabidae) and crickets (Gryllidae) can be important sources of weed seed and insect mortality in agricultural systems (Rebek et al. 2005, Westerman et al. 2008, Lundgren et al. 2013). Seeds consumed include common weed species such as giant foxtail ( Setaria faberi ), redroot pigweed ( Amaranthus retroflexus ), velvetleaf ( Abutilon theophrasti ), and common lamb s quarters ( Chenopodium album ) (Kirk 1972, Kromp 1999, White et al. 2007). Seeds on the soil surface are the most readily co nsumed (White et al. 2007). Though there is some evidence that carabid larvae primarily consume seeds, they may also eat microorganisms, plant roots, or small soil - dwelling insects (Kirk 1972, Blubaugh and Kaplan 2015). Peak foraging activity of several gr anivorous adult carabid species occurs in the fall, synchronized with the release of grass seeds (Tooley and Brust 2002). Fresh, hydrated seeds are preferred (Law and Gallagher 2015). Taken together, the literature suggests that invertebrate granivores can be effective predators of newly dispersed weed seeds in agricultural settings. 4 Pollinators . In response to decreasing honey bee populations worldwide, attracting and maximizing the efficacy of wild bees and syrphids as pollinators has become of increasi ng interest (Isaacs and Kirk 2010, Petersen et al. 2013 , Garibaldi et al. 2015 ). A recent review suggests that the decline in managed and wild pollinators can be attributed to the combined effects of multiple stressors, including repeated long - distance tra nsport, increased disease transmission, increased exposure to a variety of fungicides and insecticides, and limited floral resources, which culminate in reduced pollinator abundance and diversity (Goulson et al. 2015). Fewer pollinators could result in dec reased crop production, as approximately 35% of food crops are pollination - dependent (Klein et al . 2007). Maintaining habitat that supports resilient and effective wild pollinator complexes is crucial to ensure continued, sustainable food production. In cu curbits, pollination is essential for proper fruit set, with inadequate pollination being associated with fruit abortion and low fruit quality (McGregor 1976, Stanghellini et al. 1997, Vidal et al. 2010). The main pollinators of cucurbits are honey bees ( A pis mellifera ), the common bumble bee ( Bombus impatiens ), and squash bees ( Peponapis pruinosa ), though the role of other pollinators is not well - understood (Smith et al. 2012). Squash bees are cucurbit specialists that are among the most effective pollina tors of cucurbit crops (Hurd et al . 1974, Terpedino 1981, Canto - Aguilar and Parra - Tabla 2000). Information on squash bee biology is generally limited. They are wild, solitary bees that nest gregariously in the soil at depths of 12 - 30cm below the surface am ong the cucurbits that they pollinate (Mathewson 1968, Hurd et al . 1974). They begin foraging as early as an hour before sunrise in synchrony with the opening of cucurbit flowers (Hurd et al . 1974). Though univoltine, females may construct multiple nests e ach year, with overwintering prepupae emerging as adults the following year (Mathewson 5 1968). Squash bees appear to be sensitive to field management practices, such as tillage and irrigation (Shuler et al. 2005, Julier and Roulston 2009). Other wild pollin ators have demonstrated higher pollination rates than managed pollinators in several cases (Garibaldi et al. 2013, Holzschuh et al . 2014, Blaauw and Isaacs 2014 , Phillips and Gardiner 2015 ). In cucumbers, wild pollinators, such as bumble bee s, have been sh own to pollinate cucumbers more effectively than honey bees, even when managed honey bee hives are added to the field (Gajc - Wolska et al. 2011 , Petersen et al. 2013 ). The addition of managed honey bee hives adjacent to or within cucurbit fields does not ne cessarily increase their abundance or density (Shuler et al. 2005). Therefore, developing a method to attract wild bumble bee s to cucurbit fields should be a priority. Habitat management to enha nce beneficial insect activity . The drivers behind insect po pulation dynamics in agroecosystems have been a subject of investigation and debate for decades. Perhaps one of the most well - known hypotheses generated to explain these patterns is the resource concentration hypothesis , which states that herbivorous insec ts are most abundant in monocultures as opposed to polycultures, because a monoculture consists of a large, contiguous area of a single plant species that provides all the necessary resources for certain pests (Root 1973). For natural enemies, adding diver sity to an agricultural field should increase biological control because it provides alternative prey, shelter, and nesting habitat, thus increasing natural enemy abundance in what is known as the enemies hypothesis (Root 1973). A diverse landscape may act to drive away herbivores by presenting them with a mix of attractive crop and unattractive noncrop plant species, of which the noncrop species may be less appropriate oviposition sites. If the herbivore encounters more inappropriate oviposition sites 6 than appropriate ones, it is more likely to leave a given area without reproducing, thus reducing pest pressure. This is known as the appropriate/inappropriate landings hypothesis (Finch and Collier 2000). Pollinator movement may also be explained by this hypo thesis. Solitary bees have been observed to spend less time in plots that lack appropriate pollen or nectar resources (Collevatti et al. 1997). If a bee repeatedly land on plants that are low - quality foraging sources, then it is more likely to leave the pl ot in search of better pollen and nectar. This could have negative implications for crop pollination and yield. Beneficial insects require resources that are not typically found in conventional agricultural fields, such as pollen, shelter, and a stable m icroclimate. The goal of habitat management for conservation biological control and pollination enhancement is to provide additional food and shelter so that beneficial insects will be more abundant and effective within cropped areas (Landis et al. 2000). Modifications to the habitat in an agricultural field can be in the form of living plants or their residues, both of which can be important in supporting beneficial insects (Langellotto and Denno 2004 , Tsitsilas et al. 2001 ). Insectary plants and windbre aks are living additions to agroecosystems that can provide insects with shelter and nutritional resources that are not provided by the crop itself. Non - crop flowering plant species are rarely found adjacent to or within agricultural fields due to intensiv e herbicide use and the perception of revenue loss from uncultivated space, but there is increasing support for the use of habitat diversification as a means to increase the number, diversity and efficacy of beneficial insects (Goverde et al. 2002, Carvell et al. 2006, Blaauw et al . 2012). Mulches and nest boxes are manipulations that can provide nesting habitat, shelter, and favorable microclimate to beneficials. 7 Habitat can be managed at two different spatial scales: at the landscape or local level. Land scape level habitat management can involve increasing the amount of natural area within farms and can be effective (Tscharntke et al 2008) . The management of expansive landscapes is hindered by the fact that landowners with large contiguous areas are relat ively rare, so land management decisions are often made by multiple landowners who have competing interests. Local level habitat management on the other hand is more possible for vegetable growers who typically grow annual crops that are frequently rotated ; therefore these growers need habitat management methods that can be implemented over a short period of time in a well - defined agricultural field. Kremen et al. (2011) conclude in a meta - analysis that landscape scale habitat manipulation benefit generalis t natural enemy abundance and efficacy . Generalist predators are desirable components of a biological control program because of their flexibility in prey selection, which allows them to reduce the abundance of a variety of pests. Crops can be attacked by multiple pests at once, making the attraction of generalist natural enemies to fields via habitat management an appealing option. Intercropping, cover cropping, polycultures, and strip tillage are forms of within - field habitat manipulation that can affec t the arthropod community on a local scale. Specialist, rather than generalist, natural enemies tend to benefit the most from local scale habitat manipulation (Kremen et al. 2012 ). Attracting specialist natural enemies can be useful in addressing speciali st pest pressure. The parasitoid Cotesia rubecula for example has higher abundances in more complex local habitats, aiding in the control of the Brassica specialist herbivore Pieris rapae (Bryant et al. 2014). Many insects, such as cucumber beetles and squ ash bugs, specialize in using cucurbits as hosts. The identification of local scale habitat management techniques that benefit their natural enemies is thus of great importance. 8 The addition of flowering plants and fallow fields adjacent to cultivation can increase the abundance of bees and natural enemies found within the field itself (Long et. al 1998, Rebek et al. 2005, Wanner et al. 2006, Fiedler et al . 2008). Even plants traditionally considered to be weeds can contribute to beneficial insect enhancem ent. In cucurbits, natural enemy abundance was greater in fields adjacent to weeds or pigeon peas ( Cajanus cajan ) compared to bare ground (HansPetersen et al. 2010). Since growers eliminate weeds in and around their crops, the addition of insectary crops i nto undisturbed areas around a field may be a more viable option for biological control improvement in this system. Habitat management for pollination . The vast majority of the literature on habitat manipulation concerns natural enemies and pest control rather than pollination. A meta - analysis of the effects of habitat diversification on beneficial insects could not definitively determine the effects of local versus landscape scale habitat manipulation on bees due to the relative lack of published litera ture on the topic (Kremen and Miles 2012). What is known is that bees tend to be sensitive to environmental changes or human activity and require additional food and resources (Tuell et al. 2008, Williams et al. 2010, Winfree et al. 2011). Providing addit ional nesting and foraging areas could protect against temporal fluctuations in pollinator resources (Williams et al. 2010). Preliminary evidence suggests that wild pollinators, such as the common Eastern bumble bee ( Bombus impatiens ), can pollinate cucumb er more effectively than honey bees, even when managed honey bee hives are added to the field (Gajc - Wolska et al. 2011). Cucurbits require thorough pollination to produce viable, symmetrical fruit (Stanghellini et al. 1997). Therefore, attracting wild poll inators to agricultural fields should be a priority for growers . 9 Pollinator abundance and diversity can be affected by landscape - scale habitat resources. Landscape level factors include proximity to natural areas or other habitat resources, patch size of the resources, and quality of those resources within the landscape (Kennedy et al . 2013). When grown adjacent to wooded or natural areas, the abundance of wild bees in cucumber fields tends to increase (Lowenstein et al. 2012, Smith et al. 2013). This may be due to the fact that native bees are often sensitive to environmental disturbances and require additional food and nesting resources that are more easily obtained from natural areas (Tuell et al. 2008, Williams et al. 2010, Winfree et al. 2011). Proxim ity to natural areas can increase the amount and diversity of wild bees in agricultural fields by providing nesting and nutritional resources, increasing the - level resources available are also factors in pollinator diversity and abundance. In Michigan and other temperate areas, larger patches of undisturbed, diverse floral resources enhance pollinator and natural enemy activity more than small patches of less diverse floral resources or un managed areas (Meyer et al. 2007, Blaauw and Isaacs 2012, 2014). However, the effects of landscape fragmentation and vegetative diversity on wild pollinators are generally considered weaker than those of local disturbance or diversification (Kennedy et al. 2013). Few studies have examined the effects of local - scale field management on pollinators. Types of local level management include floral and nesting resources located within or adjacent to cropped areas (Kennedy et al. 2013). Bees are central place f oragers, meaning that the location of nesting habitat relative to the crop itself is important to their relative abundance within an agricultural field (Lonsdorf et al . 2009). In one study, ground nesting squash bees ( Peponapis pruinosa ) were three times m ore abundant in no - till squash fields than in intensively tilled squash fields (Shuler et al. 10 the squash plants at depths of 12 - 20cm below the soil surface (Hurd et al. 1974, Julier and Ro ulston 2009). Conventionally plowed fields, which disturb soil as deep as 50cm, may disturb overwintering and nesting squash bees (Hurd et al. 1974, Julier and Roulston 2009). Ground nesting bees typically prefer sloped, bare, uncompacted soil for nesting, which can be difficult to find in conventionally prepared fields (Sardiñas and Kremen 2014). Many wild bees, including squash bees, prefer to nest adjacent to or among their preferred host plants (Julier and Roulston 2009). The effect of mulching on wild bees is unclear, but it is believed to attract wild bees nesting sites (Shuler et al. 2005, Julier and Roulston 2009). Squash bees are among the most effective p ollinators of squash and pumpkin, so their conservation within areas where these crops are grown is of great importance (Winfree et al. 2011). Many other native bee species contribute to cucurbit pollination, but their roles are even less well - studied. Whi le the evidence is promising, whether these habitat manipulations increase crop quality or yield remains an open question. The effect of bee activity on agricultural settings has proven difficult to quantify. Shackelford et al. (2013) conclude in a meta - an alysis that pollinators and natural enemies may have compatible resource and thus similar habitat management requirements. Taken together, the literature suggests that habitat management may enhance pollination and pest control in cucurbits, but that furth er investigation is needed. Thesis objectives . This project aimed to quantify the effects of habitat management for conservation biological control and pollination in cucurbit fields and its impact on the cucurbit arthropod community. The first objective examined the effect of mulch and reduced tillage on the arthropod community in acorn squash ( Cucurbita pepo var. turbinata). The second objective 11 examined the effect of the inclusion of within - field flower strips on the arthropod community in slicing cucu mbers ( Cucumis sativus ) with a particular focus on pollinators. 12 CHAPTER 2: The effect of conservation tillage and cover crop residue on beneficial insects and weed seed predation in acorn squash ( Cucurbita pepo var. turbinata) . Introduction Herbivory in cucurbits can reduce yield by diverting energetic resources away from fruit production and towards defense (Hladun and Adler 2009). In addition to direct damage, insects can also harm cucurbits by vectoring diseases such as bacterial wilt ( Erwinia trach eiphila ) in squash (Shapiro et al. 2014). Expenditures for pest insect, weed, and disease management in these crops can exceed $100 per acre per growing season for pesticide applications alone (Barnett 2012). Despite these costs, yield losses due to insect s remain high (Adams and Riley 1997, Schmidt et al . 2014, NASS 2014 ) . Beneficial insects, including predators, parasitoids, and pollinators, require resources that are not typically found in conventional agricultural fields, such as food, shelter, and a stable microclimate. The goal of habitat management is to provide additional food and shelter so that beneficial insect will have greater stability (Landis et al. 2000). Modifications to the habitat in an agricultural crop field can be in the form of liv ing or nonliving elements, both of which can be important in supporting beneficial insects (Langellotto and Denno 2004). For example, insectary plants are living additions to agroecosystems that can provide insects with energetic and nutritional resources not provided by the crop itself. The addition of plant materials, such as mulches between crop rows, is a form of habitat manipulation that can provide nesting habitat, shelter, and favorable microclimate to beneficials. Growers often use conservation till age techniques, such as strip tillage, and mulches to protect soil quality by reducing runoff, erosion, 13 and soil compaction (Gebhardt et al. 1985, Luna et al. 2012). The presence of cover crop residues can improve natural enemy abundance (Hooks et al. 2011 , Bryant et al. 2013) and performance (Lundgren and Fergen 2010, Bryant et al. 2014) in other cropping systems. Conservation tillage and mulching may enhance natural enemy activity by reducing disturbance and improving habitat complexity, protecting natura l enemies from intraguild predation and environmental extremes (Landis et al. 2000, Finke and Denno 2002, Langellotto and Denno 2004). Insect pest s , such as Diabrotica undecimpunctata (Mannerheim, 1843) (Coleoptera: Chrysomelidae) (spotted cucumber beetle s) , squash vine borer ( Melittia cucurbitae , Lepidoptera: Sesiidae) and Diabrotica virgifera virgifera (LeConte, 1868) (Coleoptera: Chrysomelidae) (striped cucumber beetles) and Anasa tristis (De Geer, 1773) (Hemiptera: Coreidae) (squash bugs), are important pests of cucurbits. The identification of local scale habitat management techniques that benefit their natural enemies is thus of great importance. I nsects such as ground beetles (Carabidae) and crickets (Gryllidae) can be important sources of weed seed and insect mortality in agricultural systems (Rebek et al. 2005, et al. 2006, Westermann et al. 2008, Baraibar et al. 2012, Bagavathiannan and Northsworthy 2013, Lundgren et al. 2013). Seeds consumed include common weed species, such as giant fox tail ( Setaria faberi ), redroot pigweed ( Amaranthus retroflexus ), velvetleaf ( Abutilon theophrasti ), and common lambsquarters ( Chenopodium album ) (Kirk 1972, Kromp 1999, White et al. 2007). Seeds on the soil surface are the most readily consumed ( Westerman et al. 2003, White et al. 2007). Though there is some evidence that carabid larvae primarily consume seeds, they may also eat microorganisms, plant roots, or small soil - dwelling insects (Kirk 1972, Blubaugh and Kaplan 2015). Peak foraging activity of sever al granivorous adult carabid species occurs in the fall, synchronized with the release of grass seeds (Tooley and Brust 2002). Fresh, 14 hydrated seeds are preferred (Law and Gallagher 2015). Taken together, the literature suggests that invertebrate granivore s can be effective predators of newly dispersed weed seeds in agricultural settings. Tillage and mulch treatments can affect seed predation. Under strip - tillage, seeds tend to remain at the soil surface, where they would likely face greater levels of pre dation than if they were buried during conventional tillage (Brainard et al. 2013). Strip tillage reduces disturbance for both weeds and seed predators, potentially increasing their populations relative to conventionally tilled plots (Brainard et al. 2013 , Eyre et al . 2013 ). However, c onventionally tilled fields have been shown to have greater granivore activity density than no - till fields and lower weed pressure (Westerman et al. 2003 , Liebman and Davis 2000, van der Laat et al. 2015 ) . These results howev er have not been consistent , varying greatly by crop, year, and study (Brainard et al. 2013). The aim of this study was to quantify the effects of conservation tillage and mulch ing on the arthropod community and weed seed predation in acorn squash ( Cucur bita pepo var. turbinata) to identify habitat management techniques that enhance natural enemy activity. I hypothesized that mulching and reduced tillage would increase natural enemy abundance and activity and increase predation of seeds of important weed specie s. Materials and M ethods Field plots. The field trial on reduced tillage and mulching took place at the Southwest Michigan Research and Extension Center in Benton Harbor, Michigan (42° 4'57.01"N, 86°21'16.13"W) in 2014 and 2015 in two separate fie lds approximately 265m apart. Major field plot operations are summarized in Table S. 1. The experiments in both years had four treatments, a combination of 15 tillage and ground cover factors , each with two levels: strip - tillage or full tillage, and cover crop mulch or no cover crop mulch (bare). Treatments were organized in a split plot design with six replications . Tillage was the main plot factor, and cover crop mulch the subplot factor. In October 2013 and 2014, the entire 31x97.5m field was disked and pla nted with winter rye ( Secale cereal ) at a rate of 67.25/ha using a Great Plains Compact Drill 3P606NT (Land Pride, Salina, KS, USA). At the end of May, Roundup (Monsanto Company, St. Louis, MO)(glyphosphate) and ammonium sulfate were applied to plots conta ining the bare treatments. Due to insufficient rye emergence in both years , additional rye mulch was added to the cover crop treatment plots before tilling at a rate of 0.41kg/m 2 . In all plots, 19 - 19 - 19 (N - P - K) fertilizer at a rate of 86.25kg/ha was applie d. Tillage treatments were applied in the first week of June in 2014 and 2015. In strip - tilled plots, a single row Unverferth Zone Builder 120 (Unverferth Manufacturing Co, Inc., Kalida, OH, USA) with strip building attachment, burming disks, and rolling b asket was used to apply the strip tillage treatment. Full tillage treatment was applied using a John Deere model JD F835 moldboard plow (Deere & Company, Moline, IL). The entire field was then planted with acorn squash ( Cucurbita pepo 2014: Seigers Seed Company, Holland, MI, USA; 2015: SeedWay, Hall, NY) using a Matermacc Magicsem series 8000 precision vacuum planter (Via Gemona, 18, 33078 San Vito al Tagliamento PN, Italy). Seeds were planted 40.64cm apart within the rows with 1.5m separating the rows. Individual plots were 5.5x15m and contained three rows of acorn squash. Fo liar arthropod s ampling. To determine the effect of tillage and mulching treatments on the arthropod community, insects were sampled on the squash lea ves and on the ground in each plot. Insects on foliage were visually sampled in the center row of each plot on 10 randomly selected 16 whole plants during the first two weeks following squash emergence. Once the plants had approximately five leaves each, the numbers of insects on 10 randomly selected squash leaves in the central row were recorded. Insects were identified to major taxonomic groups in the field. Weekly a ctivity density s ampling. Two covered pitfall traps per plot were deployed 3m apart in the center of the plot slightly offset from the central squash row. The traps were constructed from 946.4mL cups (Dart Container Corporation, Mason MI, USA) containing approximately 200mL of a 50% propylene glycol, 50% water solution. Traps were covered with metal lids, to protect them from rain, that were raised approximately 4cm above the trap. Pitfall traps were deployed for a week (+/ - 1 day), then the contents were strained in the field through gauze. Samples from individual traps were preserved in 75% et hanol, then stored at - 20°C in lab. Insects from pitfall traps were identified under a microscope to major taxonomic groups in the laboratory (Marshall 2006, Bousquet 2010, Albert J. Cook Arthropod Research Collection). Arthropod abundance was analyzed by taxonomic group and sampling method with Generalized Linear Mixed Models using Laplace approximation and Poisson distribution with tillage and mulch as independent variables and tillage as the main effect. The interaction of tillage, mulch, and samplin g date were nested within block as random effects. Due to a highly significant date effect, but low sample size for each individual date, the data were combined into three temporal bins: early ( July 3 - 16), mid ( July 25 - August 14) and late (August 20 - Septem ber 4) season. Where main effects were significant ( - Kramer a djusted least - square means tests were performed to determine differences among treatments (PROC GLIMMIX, SAS 9.4, SAS Institute, Cary, NC, USA). Voucher specimens of arth ropods that 17 Arthropod Collection. Weed s eed p redation. To determine the activity density of weed seed predators, the disappearance of sentinel weed seeds from the fi eld plots on three dates at the end of the growing season was evaluated . Three species of commonly occurring weed seeds were used: Powell amaranth ( Amaranthus powellii) , common lambsquarters ( Chenopodium album ), and giant foxtail ( Setaria faberi) . In each plot, seeds of each species w ere deployed in separate 15cm diameter Petri dish arenas (VWR International, Radnor, PA, USA). Seeds were placed on the surface of 100mL of general - purpose sand (KolorScape, Oldcastle Materials, Atlanta GA, USA). Each arena con tained 100 seeds of a single weed species as counted by a Seedboro Model 801 COUNT - A - PAK Seed Counter (Seedburo Equipment Co., Des Plaines, IL). Three, 15cm diameter Petri dishes were pl aced at the center of each plot . Two pitfall traps per plot were deplo yed concurrently as described previously to measure weed seed predator activity density. Weed arenas and pitfall traps were collected from the field after 48 hours. No rainfall occurred during the period of deployment. Sampling took place on September 6 - 8 and 23 - 25 in 2014. In 2015, sampling occurred on: August 26 - 28, August 31 - September 2, September 5 - 7, and September 13 - 15 . Remaining weed seeds were frozen at 20°C to prevent germination and kill any other organisms inside the arenas . The arenas were allow ed to dry at room temperature for 48 hours before sifting. Powell a maranth and common lambsquarters seeds were separated from the sand using a standard #35, 500 micron sieve. A #30, 600 micron sieve was used to isolate the giant foxtail seeds. The number o f remaining fully - intact weed seeds were counted under a microscope and recorded. Pitfall traps were collected and processed as described previously. 18 Voucher specimens of arthropods that were collected as part of this project are kept at Michigan State Uni Differences in seed survival and seed predator abundance were analyzed by taxonomic group and sampling method and treatment with Generalized Linear Mixed Models using Laplace approximation and Poisson distribution with tillage and mulch as the main effects. Treatment was nested within block as a random effect . pairwise Tukey - Kramer adjusted least - square means tests were performed to determine differences among treatments (PROC GLIMMIX, SAS 9.4, SAS Institute, Cary, NC, USA) . The activity density of Gryllidae and Harp alus spp. and seed removal by treatment and year during seed predation trials were correlated using Pearson correlation coefficients for responses that exhibited significant differences according to generalized linear mixed models (PROC CORR , SAS 9.4, SAS Institute, Cary, NC, USA). Results Foliar arthropod s ampling. In 2014, a total of 2,656 insects of varying life stages were observed on the squash leaves over all of the treatments. Of these, 73 were natural enemies and 2,557 were herbivores. The mos t frequently observed natural enemies were green lacewings (Chrysopidae) (n=19) and ants (Formicidae) (n=14); 91% of all insects recorded during foliar sampling were aphids (Aphididae), the majority of which were recorded in August 2014 during an aphid out break. Tillage treatment did not affect the abundance of the foliar herbivores (F 1,28 <0.17, P>0.05) or natural enemies (F 1,28 <0.19, P>0.05). Mulch did not affect the abundance of the foliar herbivores (F 1,28 <0.17, P>0.05) or natural enemies (F 1,28 <0.19, P>0.05). The 19 interaction of tillage and mulch was not significant for herbivores (F 1,28 <1.57, P>0.05) or natural enemies (F 1,28 <0.19, P>0.05). Fewer arthropods were observed on squash leaves in in 2015. Of the 746 arthropods observed, the most frequently encountered were thrips (n=453), aphids (n=111), and squash bugs ( Anasa tristis ) (n=44). Natural enemies were especially rare, accounting for only 54 (7.2%) of the total arthropods encountered. Tillage and mulch treatments did not significantly affect the abundance of herbivores or natural enemies observed on squash leaves at any point in the season (F 1,459 <1.92, P>0.05). Weekly a ctivity d ensity sampling . Pitfall trap catch composition for both years is summarized in Figure 2.1. A total of 14,761 arthro pods were captured in pitfall traps in the 2014 season. Out of these , 26% were springtails (Collembola) (n=7,570), 13% were ants (Formicidae) (n=3,357), 11% were rove beetles (Staphylinidae) (n=2,957), 7% were spiders (Araneae) (n=1,763), and 5% were grou n d beetles (Carabidae) (n=1,242) (Table S.2 ) . Adult carabids had significantly higher activity densities in full - tilled plots compared to strip - tilled plots in July, early in the season (F 1,77 =4.67, P<0.04) (Fig. 2.2) . Mulch treatment did not affect early season carabid activity density (F 1,77 =0.01, P>0.05) (Fig. 2.2) . Mulch, tillage, and the interaction of mulch and tillage did not affect mid - season carabid activity density (F 1,55 <1.98, P>0.05) (Fig. 2.2) . The activity density of carabids found late in t he season was not affected by tillage (F 1,77 =0.2, P>0.05) (Fig. 2.2) . However, unmulched plots had significantly greater carabid activity density for late season dates (F 1,77 >6.5, P<0.02). The interaction between tillage and mulch treatment was not signif icant for carabid activity density during the entire season (F 1,32 <8.2, P>0.05) (Fig. 2.2) . 20 In 2014, t he majority of carabids collected were of the genus Harpalus (51%, n=635). Early season activity density of Harpalus spp. was not significantly affected by tillage, mulch, or their interaction (F 1,27 <1.18, P>0.05) (Fig. 2.2) . Mid - season activity density of Harpalus spp. was marginally significantly increased in unmulched plots (F 1,32 >7.38, P<0.07) (Fig. 2.2) . Late - season Harpalus spp. activity density was significantly increased in full - tilled unmulched plots compared to strip - tilled mulched plots (t= 3.10, df=92, P< 0.01) (Fig. 2.2) . The activity densities of all other arthropods were not significantly affected by tillage or mulch treatment or their intera ction at any point during the season (F 1,32 <1.32, P>0.05). In 2015, a total of 24,785 arthropods were collected in pitfall traps. Collembola (n=8,292), Staphylinidae (n=3 , 857), Formicidae (n=2,998), Gryllidae (1,549), and Carabidae (n=864) were the most frequently captured arthropods. Of the carabids captured, 64% of them were identified as members of the genus Harpalus (n=551). Treatment effects were only significant early in the season ( F 1,66 > 4.67 , P< 0.01) The activity density of adult carabids was s ignificantly greater in full - tilled plots than strip - tilled plots early in the season (t=6.74, df=66, P < 0.01) (Fig. 2.2) . Significantly more spiders, crickets, and grasshoppers were observed in early season mulched plots compared to unmulched plots, regard less of tillage type (t<8.02, df=66, P < 0.05) (Fig. 2.2) . The activity densities of all other arthropods were not significantly affected by tillage or mulch treatment or their interaction at any point during the season (F 1,32 <1.32, P>0.05). 21 22 Weed see d predation. Results from the seed predation trials are summarized in Figures 2.3 and 2.4. In 2014, a total of 203 arthropods were captured during the weed seed predation trials. 23 Specimens captured included spiders (Araneae, 17%) and ground beetles (Carabi dae, 47%), with 27% of all arthropods belonging to the Harpalus genus . Harpalus spp. had significantly higher activity densities in bare plots than in mulched plots (t=2.74, df=21, P= 0.02). The activity densities of all other taxa were not significantly af fected by tillage, mulch, or their interaction (F 1,41 <7.30, P>0.05). In 2015, a total of 2,653arthropods were captured during weed seed predation trials over four sampling dates. The majority of specimens captured were Collembola (20%), Formicidae (18%) . a nd Harpalus spp. (15%). Harpalus spp. had significantly higher activity densities in full - tilled plots than in strip - tilled plots (t=2.24, df=115, P< 0.03). Gryllidae demonstrated significantly higher activity densities in strip - tilled plots than in full - ti lled plots (t=2.83, df=115, P< 0.03). Staphylinidae demonstrated significantly higher activity densities in full - tilled , mulched plots than in strip - tilled and mulched plots (t=0.34, df=115, P< 0.01), while collembolans had significantly higher activity dens ities in in mulched plots (t=3.49, df=115, P< 0.01). The activity densities of all other taxa were not significantly affected by tillage, mulch, or their interaction (F 1,41 <7.30, P> 0.05). In 2014, Amaranthus powellii and C. album seed survival were not si gnificantly affected by tillage or mulch treatment (F 1,17 <0.38, P>0.05). Setaria faberi seed survival was significantly higher in strip - tilled plots compared to full - tilled plots, regardless of mulch treatment (t= - 3.14, df=17, P <0.01). In 2015, A. powell ii survival was significantly higher in mulched plots than in unmulched plots, regardless of tillage (t = - 4.31 , df= 54 , P <0.01 ). Significantly more C. album seeds were recovered from strip - tilled plots with rye mulch than all other treatment combinations (t= - 5.43 , df=58, P< .01). Significantly more C. album seeds survived in strip - tilled a nd unmulched plots than in full - tilled unmulched plots, (t = - 2.74 , df= 54 , P <0.04). Survival of S. faberi was not affected by treatment (F 1,55 < 4.95 , P> 0.05). Giant foxtail see d removal and 24 Harpalus spp. activity density were not correlated in 2014 and 2015 (R 2 <0.7, df=6, P>0.05). Common lambsquarters seed removal and Harpalus spp. activity density were not correlated in 2015 (R 2 <0.5, df=7, P>0.05). Giant foxtail seed removal an d Gryllidae activity density were not correlated in 2014 and 2015 (R 2 <0.7, df=7, P>0.05). Common lambsquarters seed removal and Gryllidae activity density were not correlated in 2015 (R 2 <0.5, df=19, P>0.05). 25 26 27 28 29 Discussion Overall. Grower s are increasingly interested in us ing conservation tillage techniques, such as strip tillage, and mulches to protect soil quality by reducing runoff, erosion, and soil compaction (Luna et al. 2012). Other studies have found that the presence of cover crop residues can improve natural enemy abundance (Hooks et al. 2011, Bryant et al. 2013) and performance (Lundgren and Fergen 2010, Bryant et al. 2014) in other cropping systems. Conservation tillage and mulching may enhance natural enemy activity by reducing disturbance and improving habitat complexity, protecting natural enemies from intraguild predation , environmental extremes , and disturbance (Landis et al. 2000, Finke and Denno 2002, Langellotto and Denno 2004). Given this information, natural enemy pres ence and activity would be expected to be the greatest in strip - tilled plots with rye mulch, as this type of management provides less invasive tillage and greater habitat complexity. While foliar arthropods did not respond to the treatments applied, natura l enemies of insects and weed seeds tended to be more abundant in full - tilled plots. Rates of seed predation aligned with this, with fewer seeds surviving in low complexity, high disturbance plots. When considering pitfall trap data, it is important to ke ep in mind the limitations of the sampling method itself. Rather than measuring the true abundance or diversity of the arthropods captured, it provides an estimate of the amount of ground - dwelling arthropod movement in the immediate area, with a bias towar ds larger - bodied specimens such as carabids (Spence and Niemela 1994, Duelli and Obrist 1998). T his chapter underlines the importance of considering the context of a given study before generalizing their re sults to all cropping systems, regions , and 30 years, as arthropod response to tillage and mulch treatment was not found to be consistent between years in this study . Foliar arthropod sampling . The a rthropod community observed on squash leaves was not affected by mulch, tillage, or their combination . Other studies have shown that the use of reduced tillage and mulching can reduce foliar herbivore populations presumably by improving within - field natural enemy habitat (Langellotto and Denno 2004, Bryant et al. 2013, Hinds and Hooks 2013). In this study however , significant effects of tillage and mulch on foliar arthropods were not demonstrated . The efficacy of conservation tillage in improving within - field biological control may take several years to take full effect, as is the case with soil health (Abawi and Widmer 2000). Repeating the study in the same field for several years may elucidate the long - term effects of tillage and mulching on the foliar arthropod community. Weekly activity density sampling . In the 2014 samples, m ulch was a more important facto r in determining carabid activity density, with sample dates closer to the date of tillage show ing stronger tillage effect . The importance of tillage in early season activity density was reinforced by the early season pitfall samples in 2015 (Fig. 2. 2) . Ti llage may be important in long - term population health of carabids and other arthropods because tillage, especially full tillage, may disrupt immature and overwintering stages ( Carmona and Landis 1999, Landis et al. 2000, Blubaugh and Kaplan 2015). In the s hort term however, it may make movement and digging, and thus finding prey, easier. The effect of tillage and mulch on s piders was variable between years. Spiders were not affected by treatment in 2014, but had significantly higher activity densities in mu lched plots in early 2015. As ground - dwelling predators, spiders typically exhibit strong 31 sensitivities to tillage and mulch ing practices . Increased habitat complexity , provided by mulch in this case, is typically favored by spiders and other predators ( Ri echert et al. 1990, Rypstra et al. 1999, Landis et al. 2000 , Snyder and Wise 2000, Bryant et al. 2013, Schmidt et al . 2014 ). S eed predation. In both years, weed seed survival tended to be the greatest in mulched plots , with the survival of seeds based on tillage treatment being more variable (Fig. 2.4). This indicates that seeds tended to be removed at a higher rate in unmulched plots. Perhaps mulch in this case reduced measured activity density of granivorous arthropods by making it more time consuming t o forage as they navigated through the mulch. Alternative food sources may have also been available either in the form of the seedheads of the rye mulch itself or the insects or organic matter contained therein. Unmulched plots in this study and in general tended to be weedier, providing additional habitat complexity, and alternative food sources, such as weed seeds. Granivorous arthropod activity as measured by the 48 hour pitfall traps also proved to be variable between seasons . Rates of seed predation an d the activity densities of several granivorous species were increased rom high disturbance plots , though there was no correlation between the two responses (Fig 2.3, 2.4 , 2.5, 2.6 ). The number of seeds removed from a given area is a result of a complex of species and their interaction with the treatments applied , along with other environmental factors . Full tillage can reduce the number of seeds on the surface (Brainard et al. 2013 , Blubaugh and Kaplan 2015 ) . This could increase granivore activity in full - tilled plots, as weed seeds would be relatively scarce in those areas compared to strip - tilled areas where more seeds have accumulated on the soil surface. In both years, the number of Powell amaranth and common lambsquarters seeds recovered undamaged wa s numerically greater than the number of intact Giant foxtail seeds recovered. Smaller seeds tend to be preferred by 32 granivorous insects, while larger seeds are preferred by vertebrates (Honek et al. 2003, Westerman et al. 2003, Honek et al. 2007). This su ggests that in this case , vertebrate seed predation pressure may have been higher than invertebrate predation . Crop type has been shown to have a bigger impact on granivore assemblages than field management , meaning that what works well in one crop may be less effective in another (Bourassa et al. 2008). Rates of seed predation also tend to be patchy , making it difficult to estimate (Marino et al. 1997 ). Optimizing weed seed predation may be a matter of adjusting the amount of mulch applied to the field so that it provides appropriate amounts of cover without hindering seed predator movement (Cromat et al . 1999). Dependable enhancement of seed predation by insects in squash agroecosystems may require more specialized management , indicating a need for furthe r study . 33 CHAPTER 3: Integrating flower strips for beneficial insects in cucumber ( Cucumis sativus ) . Introduction Beneficial i nsects i n a griculture . In response to decreasing beneficial insect populations worldwide, attracting and maximizing the effic acy of native pollinators and natural enemies has become of increasing interest (Isaacs and Kirk 2010, Petersen et al. 2013, Shackelford et al. 2013 , Garibaldi et al. 2014, Giannini et al. 2015 ). A recent review suggests that the decline in managed and wil d pollinators can be attributed to the combined effects of multiple stressors, including repeated long - distance transport, increased disease transmission, exposure to a variety of fungicides and insecticides, and limited floral resources, which culminate i n reduced pollinator abundance and diversity (Goulson et al. 2015). Fewer pollinators could result in decreased crop production, as approximately 35% of food crops are pollination - dependent (Klein et al . 2007). Maintaining habitat that supports resilient a nd effective pollinator complexes will be crucial to ensuring continued, sustainable food production. In cucumbers, pollination is essential for fruit set, with inadequate pollination being associated with fruit abortion and low fruit quality (McGregor 197 6, Stanghellini et al. 1997). The main pollinators of cucumber are honey bees ( Apis mellifera ), the common bumble bee ( Bombus impatiens ) , though the role of other pollinators is not well - understood (Smith et al. 2012). The squash bee ( Peponapis pruinosa ), another visitor to cucumber plants, are cucurbit specialists that are among the most effective pollinators of cucurbit crops (Hurd et al . 1974, Terpedino 1981, Canto - Aguilar and Parra - Tabla 2000 , Lowenstein et al. 2012 ). Information on squash bee biology is generally limited. They are wild, solitary bees that nest gregariously in the 34 soil at depths of 12 - 30cm below the surface in vertical burrows (Mathewson 1968, Hurd et al . 1974). Their nests are typically found among suitable host plants (Mathewson 1968, Hurd et al . 1974). They are typically considered oligolectic, collecting pollen only from Cucurbita , though they have been known to visit other hosts including cucumbers (Mathewson 1968, Hurd et al . 1974 , Lowenstein 2012 ). They begin foraging as early as an hour before sunrise in synchrony with the opening of cucurbit flowers (Hurd et al . 1974). They are univoltine ; females may construct multiple nests each year, with overwintering prepupae emerging as adults the following year (Mathewson 1968). Squash be es appear to be highly sensitive to field management practices, such as tillage and irrigation (Shuler et al. 2005, Julier and Roulston 2009). The effect of floral provisioning on squash bees is relatively unknown , though recent studies suggest that they m ay be unaffected by additional floral provisioning (Phillips and Gardiner 2015) . Other wild pollinators have demonstrated higher cucurbit pollination rates than managed pollinators in several cases (Garibaldi et al. 2013, Holzschuh et al . 2014, Blaauw and Isaacs 2014). In cucumbers, wild bumble bee s have been shown to pollinate cucumbers more effectively than honey bees, even when managed honey bee hives are added to the field (Gajc - Wolska et al. 2011). Bumble bees and squash bees are more effective pollina tors of cucurbits than honey bees (Artz and Nault 2011 , Petersen and Nault 2011 ). The addition of managed honey bee hives adjacent to or within cucurbit fields does not necessarily increase their abundance or density (Shuler et al. 2005). Therefore, attrac ting wild pollinators to cucumber fields should be a priority. Habitat m anagement f or p ollinators . Increasing pollinator diversity and abundance is a matter of providing sufficient landscape and local scale resources . Landscape level factors include 35 prox imity to natural areas or other habitat resources, patch size of the resources, and quality of those resources within the landscape (Kennedy et al . 2013). When grown adjacent to wooded or natural areas, the abundance of wild pollinators in cucumber fields increase d (Lowenstein et al. 2012, Smith et al. 2013). This may be due to the fact that native pollinators are often sensitive to environmental disturbances and require additional food and nesting resources that are more easily found in natural areas (Tue ll et al. 2008, Williams et al. 2010, Winfree et al. 2011). Proximity to natural areas can increase the amount and diversity of wild bees in agricultural capacity fo r pollinators. The size and quality of the landscape - level resources available are also factors in pollinator diversity and abundance on crops ( Winfree et al. 2007, Petersen and Nault 2014 , Wray and Elle 2015 ) . L arger patches of undisturbed, diverse floral resources enhance pollinator and natural enemy activity more than small patches of less diverse floral resources or unmanaged areas (Meyer et al. 2007). Local scale management for pollinators is also important. Types of local level management include flo ral and nesting resources located within or adjacent to cropped areas (Kennedy et al. 2013). Bees are central place foragers, meaning that the location of nesting habitat relative to the crop itself is important to their abundance within an agricultural fi eld (Lonsdorf et al . 2009). Ground nesting bees typically prefer sloped, bare, uncompacted soil for nesting, which can be difficult to find in conventionally prepared fields (Sardiñas and Kremen 2014). Many wild bees prefer to nest adjacent to or among the ir preferred host plants ( Cresswell et al. 2001, Julier and Roulston 2009 , Lonsdorf et al . 2009 , Jakobsson and Ågren 2014 ). Adding flower strips within the field itself may increase the desirability of the field for nesting and foraging, increasing the abu ndance and diversity of bees within cropped areas, thus increasing crop pollination. 36 Floral p rovisioning f or b eneficial i nsects. Non - crop flowering plant species are rarely found adjacent to or within agricultural fields due to intensive herbicide use an d the perception of revenue loss from uncultivated space, but there is increasing support for the use of habitat diversification as a means to increase the number, diversity and efficacy of natural enemies and pollinators. (Landis et al. 2000, Goverde et a l. 2002, Carvell et al. 2006, Fiedler et al. 2008, Blaauw et al 2012). The addition of flowering plants and fallow fields adjacent to cultivation can increase the abundance of beneficial insects found in cropped areas (Long et al . 1998, Rebek et al. 2005, Wanner et al. 2006, Fiedler et al. 2008 , Woodcock et al. 2014 ). Native pollinators and natural enemies are attracted to both annual and perennial flowering species in Michigan (Fiedler and Landis 2007 , Tuell et al. 2009 ). M eta - analyses have indicated that pollinators and natural enemies demonstrate greater abundances from increased local level vegetational diversity and floral availability (Kremen and Miles 2012, Shackelford et al. 2013 , Riedinger et al. 2014 ). Taken together, the literature suggests that a dding flower strips to cropped areas may enhance pollination and pest control in cucumber. Hypotheses. The inclusion of flower strips in cucumber fields will: 1) increase the abundance of natural enemies 2) decrease the abundance of herbivorous insects, and 3) increase pollinator abundance and diversity, and 4) increase cucumber yield and quality. Additionally, the effect of the flower strips was expected to be the strongest in rows of cucumbers adjacent to the flowers, meaning that the re will be greater abundance and diversity of beneficial insects and fewer pests in rows of cucumbers closest to the flowering annuals. 37 Materials and Methods Field plot establishment. and Girls Farm in Be nton Harbor, Michigan in 2014 and 2015. In 2014, the field was 201 x 402m and in 2015, it was 183 x 366m. A randomized complete block design was implemented in both years. The field was divided into six blocks with five treatments. Major field operation da tes are provided in Table S.2 . In mid - April, the field was treated with herbicides (1.18L/ha, s - metalochlor, Syngenta Crop Protection, LLC., Greensboro, NC; Command 3ME, 0.8L/ ha, 2 - [(2 - chlorophenyl)methyl] - 4,4 - dimethyl - 3 - isoxazolidinone, FMC Agricultural Solutions, Philadelphia, PA). Slicing cucumbers ( Cucumis sativus April in 2014 and 2015. Seeds were treated with a seed coat (FarMore , azoxystrobin, fludioxonil, mefenoxam, and thiamethoxam , Syngenta, Basel, Swit zerland) and planted with Presidio ( 0.75L/ha Fluopicolide, Valent U.S.A. Corporation, Walnut Creek, CA) and Admire (0.75L/ha , imidacloprid , Bayer CropScience Inc, Calgary, Alberta) . Between rows, Dual II Magnum ( 1.25L / ha , s - metalochlor , Syngenta Crop Pro tection, LLC., Greensboro, NC) and Command 3ME ( 0.8L / ha) were applied. For the flower strips, black plastic was removed in 20m long sections that were separated by 40m in rows and 12 rows (46m) between flower - strips in both years. In 2014, all flower stri ps 20m from the field edge. In 2015, flower strips were a minimum of 10m from the field edge due to an asymmetrical field shape . The following flower treatments were seeded at the end of April 2014 and 2015: 1) Brassica hirta (yellow mustard , var. ), 2) Lobularia maritima (sweet alyssum ) 3) Fagopyrum esculentum (buckwheat), 4) Trifolium incarnatum (crimson clover), or 5) cucumbers (control). In 2014, Cucumber seeds were hand planted and promptly covered with low tunnels using a transparent plastic cover. Low tunnels were not used in 2015 . Sweet alyssum and clover was 38 hand seeded while buckwheat and mustard was seeded with a Model JP - 3 Clean Seeder using a Y24 disk for mustard and a R12 disk for buckwheat (Jang Automation Co., L td, South Korea). In 2014, o ats were used as a nurse crop for the alyssum and clover seeds. In 2015, no oats nurse crop was used. over the flower - strip was opened and Select 2E C 43560 (Valent USA, Walnut Creek, CA ) (0.59L Clethodim /ha) was applied to control the oat nurse crop was applied to control the oat nurse crop In June, harvests began and the grower applied Nu Cop 50 DF ( 0.027kg/ha copper hydroxide, Albaugh Inc., Ankeny, IA) , Initiate 720 ( 1.183L/ha t etrachloroisophthalonitrile Loveland Products, Inc., Greeley, CO) plus Perm - up (0.0025L /ha permethrin, United Phophorus Inc, Trenton, NJ). In 2015, similar field management was utilized, except that the cucumber beds were not covered with low - tunnels . Sampling transects (0.77x20m) were located within the flower strips (Row 0) and 1.5m (Row 1), 5m (Row 3), and 10m (Row 5) away from the flower strips. Foliar a rthropod a bundance. In 2014 only, insects were sampled on the cucumb er leaves in each treatment plot. Insects on foliage were visually sampled in each transect on 10 randomly selected whole plants during the first two weeks following cucumber emergence. Once the plants had approximately five leaves each, the numbers of ins ects on 10 randomly selected cucumber leaves in the each transect were recorded. Insects were identified to major taxonomic groups in the field. Arthropod a bundance on s ticky t raps. Sticky traps (12x15 cm) were deployed at the center of each flower stri p in 2014 and 2015 . In 2015, a sticky trap was also deployed in row 3. Traps 39 were collected and redeployed weekly. Traps were frozen at - 20C° and identified in the laboratory to the lowest relevant taxonomic unit. Most Diptera, excluding Tachinidae and Syr phidae, were not counted . Voucher specimens of arthropods that were collected as part of this Arthropod a bundance by s weep n et. Flower - strips were sampled weekly via sweep ne t. When sampled, e ach 20m flower transect was swept 100 times. Insects were frozen at - 20C° and identified in the laboratory to the lowest relevant taxonomic unit. Most Diptera, excluding Tachinidae and Syrphidae, were not considered. Voucher specimens of arthropods that were Collection. Pollinator o bservation . Sampling for pollinators occurred between 7:30am and 12:30pm on sunny, calm days, at approximately one week intervals . Pollinators were assessed by walking along each 20m transect and recording the number and identity of all bees observed over a 10 minute period. If sight identification was not possible, pollinators were collected for laboratory identificat Bees of the Eastern United States (1962). Voucher specimens of arthropods that were collected rthropod Collection. Yield. Yield data were collected twice during harvest. The mass of all cucumbers in a 1m section within each transect were used as a measure of yield. The diameter and length of the harvested 40 cucumbers was graded in accordance with the United States Standards for Grades of Cucumbers (USDA 1997). Statistical a nalysis. Arthropod abundance by taxonomic group, sampling method , treatment , and row were analyzed with Generalized Linear Mixed Models using a Poisson distribution with treatm ent and row as independent variables and treatment as the main effect. Treatment was Tukey - Kramer adjusted least - square means tests were performed (PROC GLIMMIX, SAS 9.4, SAS Institute, Cary, NC, USA). The effect on total weight and average grade of the cucumbers harvested within the transects by distance from the flowering strips were analyzed with Generalized Linear Mixed Models using a normal distribution with treatment and row as independent variables and treatment as the main effect. Treatment was nested within block as a random effect. Where main effects were significant ( - Kramer a djusted least - square means tests were performed (PROC GLIMMIX, SAS 9.4, SAS Institute, Cary, NC, USA). Results Foliar observation . Flowering treatment, row, and the interaction between treatment and row did not significantl y affect the abundance of natural enemies or herbivores found on cucumber leaves in 2014 (F 8,5 <0.45, P>0.05). Sticky t raps o verall. In 2014, a total of 2,796 insects were collected and identified on 1 30 sticky traps deployed in the flower strips . An aver age of 21.5 insects were identified on each trap. The 41 number of traps was increased to 229 traps deployed in 2015 . A total of 6,652 insects were collected by sticky trap, 42% more than in 2014. A total of 115 sticky traps were collected from the flower st rips in 2015 , with 5,132 insects collected on these traps . In the third row of cucumbers away from the flower strips, a total of 114 sticky traps were deployed , catching a total of 1,521 insects . The mean number of insects caught on sticky traps deployed i n the flower strips and cucumbers was 44.6 and 13.3 respectively. Sticky t rap h erbivore s . In 2014, o f the 1,498 herbivores, 27.97% were leaf and t ree hoppers (Membracoidea), 23.2 % were tarnished plant bugs ( Lygus lineolaris ), and 19.2 % were leaf beetles ( Chrysomelidae ) (Fig. 3.1) . No significant treatment effects on sticky trap captures were found for the number of arth r opods in any of the herbivorous taxa (F 4,115 <1.95, P >0.05). In 2015, Membracoidea (39.35%), Lygus lineolaris (28.34%), and Alticini (8. 13%) were the most commonly occurring herbivores (Fig. 3.1) . These herbivores were most frequently trapped on sticky traps located within the mustard flower strips, where 21% of the specimens were captured across rows and treatments . C aptures on sticky tr aps for the most frequently captured herbivores were slightly lower within - cucumber areas than in the flower strips , though overall they were relatively evenly distributed. For L. lineolaris , 9.0% fewer specimens were captured outside of the flower strips than inside the strips , 3.1% fewer for the Membracoidea, and 36.8% fewer for the Alticini. No significant treatment or row effects on sticky trap captures were found for any herbivores (F 3,206 < 0.9 8 , P >0.05). Sticky t rap n atural e nemies. In 2014, t he mo st abundant of the 1,172 natural enemies collected on sticky traps were minute pirate bugs ( Orius spp., 40.19%), parasitoids (Parasitica, 34.22%) 42 and lady beetles (6.72%) (Fig 3.2) . Sweet alyssum had the greatest number of natural enemies captured (n=342) , while the control treatment had the least (n=128). Pre and during harvest abundances of lady beetles and minute pirate bugs collected by sticky trap in the floral strips were significantly different among treatments (F 4,93 >3.39, P <0.02) (Fig. 3.3) . Sign ificantly more lady beetles were f ound on the sticky traps in the buckwheat and sweet alyssum treatments than control cucumber only plots (t>1.32, df=93, P <0.05) (Fig. 3.2). Significantly more minute pirate bugs were found on sticky traps placed in mustard and sweet alyssum stri ps compared to control cucumber - only plots (t>3.32, df=93, P <0.05) . In 2015, a total of 3,467 natural enemies were captured on sticky traps. Parasitica (48.41%), Orius spp. (37.10%), and Araneae (7.36%) were the most commonly trap ped natural enemies (Fig. 3.2) . Across the treatments, natural enemies were most frequently captured within the flower strips, where 59.1% of the natural enemies were caught. The greatest number of natural enemies were caught on sticky traps located within mustard flower strips (n=742) and the fewest were caught on traps located within the corresponding area of the control plots (n=250). Both treatment (F 3,206 >137.04, P < 0. 01) and row (F 3,206 > 241.83, P <0. 01 ) significantly affected the number of minute pir ate bugs on sticky traps (Fig. 3.3, 3.4) . . Minute pirate bugs were collected more frequently on traps located within the mustard strips compared to other treatments and rows (t>31.57, df= 206 , P <0.0001) Both treatment (F 3,206 > 196.25, P <.0001) and row (F 3, 206 > 61.44, P <.0001) location significantly affected whether parasitoids were collected on sticky traps (Fig 3.3) . Parasitoids were collected more frequently on traps located within the mustard strips compared to other treatments and rows (t>31.57, df= 206 , P <0.0001). They were also significantly more abundant in the cucumber areas of buckwheat flower strips plots than in 43 other treatments (t> 12.49, df= 206, P <0.0001) . All other natural enemy taxa were unaffected by treatment, row, or their interaction (F 3, 206 <0.77, P >0.05 ) . 44 45 46 Sweep net overall . In 2014, a total of 2,863 arthropods were collected and identified from 90 sweep net samples collected from the flower strips over a five week sampling period . An average of 30 .1 arthropods were identified from each transect. Sweet alyssum transects yielded nearly half (47.6%) of all arthropods collected by sweep net (n=1,363). A total of 90 sweep samples were collected from the flower strips in 2015 over a five week sampling period, with 3,629 arthropods collected. A mean of 40.2 arthropods per sample 47 were captured. The greatest number of arthropods were found samples from mustard (n=1,494), followed by sweet alyssum (n=1,076), and buckwheat (n=1,059). Sweep net herbivores. A total of 2,305 herbivores we re collected by sweep net in 2014. The most abundant arthropods sampled were Lygus lineolaris (40.56%), Miridae (38.74%), and Curculionidae (4.25%). The numerically greatest number of herbivores were found in samples collected from sweet alyssum transects (n= 1,119) while buckwheat had the fewest (n=375). Flowering treatment did not significantly affect the abundance of herbivores collected by sweep net from the flower strips pre and during cucumber harvest (F 4,70 <0.21, P>0.05). In 2015, 2,322 herbivores w ere collected, the majority of which were Memb racoidea, (37.7 %), Lygus lineolaris (28.0%), and Alticini (9.4 %). The greatest number of herbivores were found in samples collected from mustard transects (n= 1,006) while buckwheat had the fewest (n=614). Flow ering treatment did not significantly affect the abundance of herbivores collected by sweep net from the flower strips pre and during cucumber harvest (F 2,78 <0.01 , P>0.05). Sweep net n atural e nemies. A total of 593 natural enemies were collected via swee p net in 2014. The most abundant arthrop ods sampled were identified as Orius spp. (40.12%), Parasitica (34.16%), and Coccinellidae (6.73%). The raw abundance of natural enemies found in sweep samples was relatively even among treatments, with mustard havi ng the most natural enemies (n=184), followed by sweet alyssum (n=175), and buckwheat (n=153). Flowering treatment did not significantly affect the abundance of natural enemies collected by sweep net from the flower strips (F 2 ,70 <0.22 , P>0.05). 48 In 2015, 1 ,145 natural enemies were collected, with Orius spp. (48.38%), Parasitica (37.07%), and Coccinellidae (7.36%) having the highest abundances. As in the previous season, natural enemies were relatively even among treatments. Buckwheat had the most natural en emies (n=405), followed by mustard (n=391), and sweet alyssum (n=349). Flowering treatment did not significantly affect the abundance of natural enemies collected by sweep net from the flower strips (F 2,78 <0.01, P>0.05). Sweep net pollinators . In 2014, 1 26 p ollinator s were collected by sweep net . The most abundant pollinators were native bees (87.30%), the majority of which were Halictidae and Andrenidae. Flowering treatment did not significantly affect the abundance of pollinators collected by sweep net from the flower strips pre and during cucumber harvest in either year (F 4,70 <0.21, P>0.8). Diversity . The diversity of insects collected in sweep net samples in 2014 and 2015 was relatively even between years, with numerically greater diversity overall observed in 2014 (Table 3.1). However, the trends between years were similar, with the greatest arthropod diversity observed in mustard samples. 49 Table 3. 1 . i ces for sweep net and sticky trap data in 2014 and 2015. Each 0.77x20m flower strip was swept 100 times once a week for five weeks. Sticky traps were deployed in the center of the flower strips at canopy height for a week. Diversity ind i ces were calculated with PC - ORD. Pollinator o bservation . A total of 478 pollinators were observed on cucumber plants in 2014 . The majority of the bees observed were squash bees ( Peponapis pruinosa ) (n=332) and honey bees ( Apis mellifera ) (n=132). The remaining bees were native species of the genera Bombus (n=7), Agapostemon (n=5), and Lasioglossum (n=2). Flowering treatment, row, and the interaction bet ween treatment and row did not significantly affect the abundance of observed honey bee s or native bees 1, 3, or 5 rows away from the flower treatments before cucumber harvest (F 8,64 <0.45, P>0.3) (Fig. 3.4) . However, significantly fewer squash bees were ob served near buckwheat and mustard plots than near cucumber only plots, regardless of distance from the flowering treatment (t>3.25, df=93, P <0.02) (Fig. 3.4). Row and the interaction between treatment and row did not significantly affect the abundance of any bees observed (F 2,64 <1.23, P>0.05 ). In 2015, a total of 5,068 pollinators were observed. Apis mellifera (61.27%), Syrphidae (36.50%), and Peponapis pruinosa (0.32%) were the most frequently observed. Of those, a total Shannon's Diversity Index (H) 2014 2015 Sweep Net Buckwheat 0.58 0.34 Mustard 0.63 0.40 Alyssum 0.66 0.37 Sticky Traps Buckwheat 0.77 0.31 Mustard 0.80 0.46 Alyssum 0.65 0.38 50 of 767 pollinators were observed on cucumber plants. Honey bee s (n=617) were the most frequently observed, followed by syrphids (n=121), native bees (n=17), and squash bees (n=12). Significantly more honey bees were observed in the flower strips of the mustard and buckwheat treatments tha n in other rows and treatments (t> - 5.02 , df= 361 , P <0.01 ) (Fig 3.4, 3.5) . . The most syrphids were observed in the alyssum flower strips, followed by the buckwheat and mustard strips (t> - 10.66, df=361, P <0.01) (Fig 3.4, 3.5) . Significantly more native bees were observed within the flower strips of the mustard and buckwheat treatments than in other rows and treatments (t> - 25.97, df=361, P <0.01) (Fig 3.4, 3.5) . Squash bees were not significantly affected b y treatment, row, or their interaction (F 6,361 <0.05, P>0.99) (Fig 3.4, 3.5) . 51 52 Yield . In 2014, t here were no significant differences by distance from the flower strips in mass harvested per meter (F 2,73 < 2.66, P>0.05) or the interaction between flower treatment and distance (F 8,70 , F=0.46, P>0.05 ). The percentage of low - grade cucumbers harvested was not affected by treatment (F 4,70 =1.29, P >0.05), distance from flower treatment, (F 2,70 <1.48, P >0.05), or their interaction (F 8,7 0 = 0.46, P >0.05). In 2015, significantly more cucumbers were harvested 53 fr om sweet alyssum plots than the other treatments ( t> - 2.69 , df= 122 , P <0.01) . Significantly more cucumbers were harvested from row 5, the row furthest away from the floral strips , than row 1 ( t> - 2.6 4 , df= 122 , P <0.0 3 ) . However, the interaction between treatm ent and row did not significantly affect mass harvested (F 6, 122 <0. 28 , P >0.05). N o significant differences in mean grade of cucumbers harvested by treatment or row were observed (F 6,87 <0.78, P >0.05). 54 Discussion A rthropods across sampling methods we re more abundant in floral strips and less abundant in cropped areas. Cucumber r ows closest to the floral strips did not have more insects than those further away. Cucumber yield was slightly increased in sweet alyssum treatments and in the row located far thest away from the floral strips . Fruit quality was not significantly affected. Herbivores and n atural e nemies . Contrary to my predictions , the abundance of h erbivorous insects was not significantly reduced by the presence of flowers , regardless of samp ling methods. The herbivore communities within flower strips were also not significantly different from one another. F ew arthropods were observed overall on the cucumber plants or sticky traps in either year , a primary contributing factor to this may be th e use of the systemic insecticide imidacloprid at p lanting in both years . Greater numbers of natural enemies were detected in the floral strips compared to the cucumbers in both seasons . Insect abundance tends to be highest where the greatest numbers of su itable resources are located , according to the resource concentration hypothesis (Root 1973) . While the c ucumber flowers provide little nectar and pollen (Southwick et al. 1981, Masierowska 2003, Peng et al 2004) , t he floral species used here are well - esta blished insectary plants (Platt et al. 1999, Landis et al . 2000, Berndt and Wratten 2005 , Fiedler et al . 2008) . It is likely that the flowers concentrated the available natural enemies in the flower strips rather than increasing the total number of natural enemies available for biological control in the whole field . The effect of insectary plant mixes on the natural enemy community found in cucurbit systems can vary from year to year, with some years having higher abundances of key natural enemies in 55 croppe d areas while some demonstrate little effect (Grasswitz 2013). An important factor to be considered here is the use of annual versus perennial flowers. Perennial insectary mixes are thought to improve natural enemy diversity and abundance by increasing the carrying capacity of the area over time (Landis et al. 2000, Iverson et al. 2014). However, cucumbers are rotated annual crops making the improvement of the beneficial insect community with perennial plants a challenge . Another consideration is the scale of resources provided. Generally, larger areas of floral resources support greater beneficial insect abundance and diversity (Blaauw and Isaacs 2012 ). Relative to the entire field, the total area of the flower strips was small in both years, comprising les s than 0.001% of the total area of the field. Increasing the size of the within - field floral areas may improve the total number of natural enemies dispersing into cropped areas of the field; however this may be im practical for economical farming in cucurbi ts . However, floral provisioning has been employed in other agro e cosystems with some success ( Long et al. 1998, Walton and Isaacs 2011, Brennan 2013, Garibaldi et al 2014, Nayak et al. 2015), so it may be a matter of finding the optimal species and deployme nt of these resources. Pollinator s . Generally, pollinators were more abundant within the flor al strips than in cropped areas. The d istance away from the strips did not appear to significantly affect pollinator foraging on cucumber plants . Native bees occu rred at lower levels than honey bee s in the cucumber field overall, but showed a similar pattern, favoring the floral strips over the cucumbers. Honey bees and many native bees are generalists, but prefer to visit flowers with high - quality resources ( Cook et al. 2003, Cnaani et al. 2006 ). As with the natural enemies, providing larger patches of high - quality floral resources may better support pollinator populations (Blaauw 2013 ). Pollinators are highly mobile, and can cover relatively large distances propor tional to their body 56 size in search of their preferred floral resources ( Greenleaf et al. 2007, Benjamin et al. 2014, Danner et al. 2014, Geib et al. 2015 , Wright et al. 2015 ). The distance between rows may have been too small to detect a distance effect , since bees may forage as far as several kilometers away from their nests ( Greenleaf and Kremen 2006, Greenleaf et al. 2007, Londsdorf et al. 2009) . Honey bee s are one of the primary pollinators of cucumbers in North America, yet they do not appear to have been drawn to the cucumbers by the floral resources provided. Rather, they appear to have concentrated within the flower strips without dispersing into the surrounding cropped areas or being drawn away from the cucumbers (Fig . 3.5). Bees and other highly m obile insects have demonstrated sensitivities to the quality of the landscape as a whole, meaning that local - scale management may be insufficient support for their populations ( Shackelford et al . 2013, Petersen and Nault 2014 , Kremen et al. 2015, Park et al. 2015 ). Additionally, the floral strips may have had some exposure to the systemic insecticides applied to the cucumbers at planting, which may have had a repelling effect, though this cannot be known for certain (Easton and Goulson 2013). Squash bees were observed in 2014 and in much lower numbers in 2015 . In 2014, they were significantly less abundant in buckwheat and mustard plots than in cucumber only or alyssum plot, a finding that was not repeated in the subsequent year (Fig 3.4). Squash bees are not reliably attracted to non - cucurbit hosts (Phillips and Gardiner 2015). While cucumber is not a preferred host, perhaps the squash bees dispersing from nearby overwintering sites such as winter squash fields from the previous season are moderately attra cted to cucumber to obtain nectar at emergence , then seek out their preferred Cucurbita hosts. If more squash bees could be attracted to cucumber fields, perhaps with a more attractive floral intercrop or by planting cucumbers in or near old squash fields, cucumbe r pollination could be possibly be enhanced , 57 though their efficacy in cucumbers compared to other cucurbits is relatively unknown . This could be particularly effective if nesting habitat were conserved over consecutive years (Splawski et al. 2014). This may have inadvertently been the case in 2014, when the cu cumber field was adjacent to what had been a winter s quash field the previous season . Yield. Properly implemented, habitat management has the potential to increase the abundance and diversity of wild pollinator populations, increasing yield in turn (Garibaldi et al 201 5 ). However, i n the current study c ucumber yield was only significantly affected by the flower treatments in 2015 (Fig. 3.6 ) . The mass of cucumbers harvested from the plots adjac ent to sweet alyssum was significantly greater than that of the control plots. This is unexpected, as pollinators were not significantly affected by the floral treatments (Fig. 3.5). Perhaps the buckwheat and mustard strips competed with the cucumbers for abiotic resources, such as light and nutrients, as they are larger, more vigorous plants than the sweet alyssum. C ucumbers tend to be variable in size , weight, and shape and produce fruit for several weeks, during which time cucumbers are harvested daily. Increasing the area of cucumbers harvested for yield could provide a more robust estimate of the amount and quality of cucumber yield . H ydration, pollination, nutritional, and varietal differences can all impact the number and quality of cucumbers harveste d (Isamail and Ozawa 2007, Bhardwaj 2014, Rahil and Qanadillo 2015, Motzke et al. 2015). The interaction of these factors in combination with the fact th at pollinator visitation to cucumber plants was not increased by the treatments applied likely explains the weak treatment effect on yield. 58 CHAPTER 4: Conclusions and Future Directions The purpose of this project was to quantify the effects of habitat management for conservation biological control and pollination in cucurbit fields and its impact on t he cucurbit arthropod community. In chapter two , the effect s of mulch and reduced tillage on the arthropod community in acorn squash were examined. Natural enemies of weed seeds and insects were expected to be more abundant in strip - tilled, mulched plots t han full - tilled, unmulched plots. The abundance of insects detected during f oliar observations did not differ among treatments, but treatment effects on ground - dwelling arthropod activity density and weed seed survival were detected . The effects of tillage and mulch on arthropods and seed survival varied by year. Generally, granivore activity density was reduced in strip - tilled plots and s eed survival was either unaffected or higher in strip tilled or mulched plots. In the third chapter, the effect s of flor al intercropping on beneficial insects and yield in a commercial cucumber field were examined. Beneficial insect abundance was expected to greater in plots containing flowers, with more beneficials found in the rows closest to the floral strips. Arthropods in the floral strips were captured with by sweep net and sticky trap, while arthropods in cropped areas were sampled with foliar observations in the first season and sticky traps in the second. Pollinators in all rows were sampled with timed transect obse rvations. Some floral treatments attracted more beneficial insects than others, but the beneficials did not disperse out to the cucumber plants. Cucumber y ield was only weakly affected in 2015 . Th e effects of tillage and mulch treatments on the arthropod c ommunity varied by season, possibly due to several important factors. The weather in 2015 was cooler and cloudier than the 59 previous year, both of which can impact insect activity, especially when sampling with pitfall traps (Duelli and Obrist 1998 , Enviro - weather - Michigan State University 2015 ). Another consideration is that the long - term management of the field sites was different. The field used in 2014 had been in cucurbit production for several years, while the field in 2015 had been fallow for an ind eterminate amount of time. The baseline local - scale arthropod communities in these areas would thus be expected to be different , as frequency and severity of disturbance can profoundly alter community structure and resilience, impacting beneficial insect a ctivity (Menge and Suterhland 1987, Turner and Dale 1998, Collins 2000, McCabe and Gotelli 2000, Landis et al. 2000 , Eyre et al. 2013 ) . However, the results from this study do not indicate consistent benefits from one tillage and mulch regime over another on natural enemy abundance or activity. In fact, the most consistent effect of strip tillage appears to be the reduction of carabid activity density. W hile there are many reasons to implement conservation tillage an d mulch, arthropod management alone may n ot be sufficient justification. Habitat management can be a powerful, sustainable tool for improving beneficial insect activity in agroecosystems. However, different cropping systems, regions, years, even fields can yield markedly different results than m ight be expected ( Bourassa et al. 2008, Fiedler et al . 2008 ). In the case of Chapter 2 , t h e effects of tillage and mulch treatments do not suggest consistent benefits of one tillage and mulch regime over another on natural enemy abundance or activity , and may even be detrimental in some cases. However, there can be benefits to using conservation tillage and mulch , meaning that the lack of dependable effects on arthropod activity shown here should not be a deterrent (Brainard et al. 2013) . Additionally, othe r studies have shown these techniques to effectively support natural enemy activity across cropping systems, especially in low - input settings ( Zehnder et al 2007, Schmidt et al. 2014, Trichard et al. 2014 , 60 Blubaugh et al. 2015). In the case of seed predati on, it may be a matter optimiz ing the amount of mulch applied to maximize weed suppression and predation (Cromat et al . 1999 , Brainard et al. 2013 ). Landscape factors, such as proximity to wooded areas, may also be important considerations in determining t he potential for tillage or mulch application to impact natural enemies (Menalled et al. 2000 , Mitchell et al. 2014 ). Perhaps tracking the rates of activity density and seed predation over several growing seasons and crop rotations would elucidate the long term effects of field preparation. It would also be informative to determine if the insects captured in the pitfall traps during the seed predation trials were actually consuming or contacting the seeds deployed, perhaps through gut content analysis or im munomarking of the seeds themselves. The relationship between field management and beneficial insect activity in squash production systems is complex and requires further study. Habitat management has been established as an effective component of integrat ed pest management and beneficial insect enhancement for many years (Landis et al. 2000) . However, this thesis research did not detect benefits of within - field floral intercropping extend ing out to the field as a whole. Planting the more promising floral s pecies, buckwheat and mustard, in unused areas of the field such as the driveways and field margins may improve the effects on beneficial insects at the local scale, similar to the use of insectary hedgerows (Morandin et al. 2014). Flowers planted in the d riveways and margins would also be subject to less insecticide exposure, which could also bolster beneficial insect populations . However, they would be at risk for being run over repeatedly by machinery and vehicles used to maintain the field, possibly red ucing their efficacy While increasing the total area of the floral strips has the potential to benefit natural enemies, pollinators, and yield, the question of whether or not the benefits of increased habitat management would outweigh the grower costs requ ired for optimal implementation remains ( van 61 Lenteren 2011, McCarthy et al. 2012, Kleijn et al. 2015). As has been concluded by other studies, the responses of natural enemies and pollinators to the addition of floral resources proved to be similar, meani ng that their management is compatible (Long et al. 1998, Otieno et al. 2011, Nicholls and Altieri 2012, Shackelford et al. 2013, Iverson et al. 2014, Morandin et al. 2014 , Duru et al. 2015 ). Planting the more promising floral species, buckwheat and mustar d, in larger patches and in unused areas of the field such as the driveways and field margins may improve the effects on beneficial insects at the local scale, similar to the use of insectary hedgerows ( Blaauw and Isaacs 2012, Morandin et al. 2014). While increasing the total area of the floral strips has the potential to benefit natural enemies, pollinators, and yield, the question of whether or not the benefits of increased habitat management would outweigh the grower costs required for optimal implementa tion remains (McCarthy et al. 2012, Kleijn et al. 2015). However, for growers to widely adopt a given habitat management strategy, yield and cost - effectiveness would have to be noticeably improved (Griffiths et al. 2008). Yield was not markedly improved b y the presence of any of the flowers added, meaning that the justification for removing those areas from cultivation is limited. However, in low - input settings, such as small, organic farms that are not as intensively managed, improvements to the habitat o n the arthropod community may become more apparent. Habitat management for beneficial insects still holds a great deal of potential to improve yield , profitability, and sustainability, but many questions as to its application in cucurbit agroecosystems re main. 62 A PPENDICES 63 APPENDIX A: Supplementary Data Table S . 1 . Major field activities in 2013 - 2015. The study took place in an acorn squash field at the Southwest Michigan Research and Extension Center in Benton Harbor, MI. F ield Operation Date 2013 2014 2015 Rye planted 14 - Oct 13 - Oct Glyphosate/ammonium sulfate applied to bare plots 10 - Oct 27 - Apr Glyphosate/ammonium sulfate applied to bare plots 27 - Apr 22 - May Glyphosate/ammonium sulfate applied to all plots 14 - May 25 - May 200 lbs of 19 - 19 - 19 applied to all plots (76 lbs/acre) 14 - May 25 - May Mulch treatments applied (0.41kg/m2 ) 5 - Jun 2 - Jun Moldboard plow, dicing, harrowing, applied to full tillage plots 5 - Jun 2 - Jun Strip tillage applied to strip - tilled p lots 5 - Jun 3 - Jun Squash planted 6 - Jun 3 - Jun Strategy 3 pints/acre and Dual 1 pint/acre 6 - Jun Bravo 720 11 - Jul 23 - Jul Ranman 23 - Jul Equus 30 - Jul Ranman 30 - Jul NuCop50 11 - Jul 30 - Jul Stand counts 16 - Jul Hand weeding 3 1 - Jul 15 - Aug Copper application 15 - Aug 14 - Aug Ranman 14 - Aug Quadris 8 oz/acre 15 - Aug Equis 1 pts/acre 15 - Aug NuCop50 3lbs/acre 21 - Aug Previcur Flex 1.2pt/acre 21 - Aug 14 - Aug Bravo 720 2pts/acre 21 - Aug Ranman 21 - Aug NuCop50 3lb s/acre 5 - Sep 21 - Aug Quadris 12 oz/acre 5 - Sep Piericure Flex 1.2 pts/acre 5 - Sep Harvest and yield measurements 16 - Sep 64 Table S.2 . Arthopods observed on squash leaves in 2014 (a) and 2015 (b) . 2014 Total insects per 20m flower transect Freq (%) Herbivores Lygus lineolaris 802 38.61 Miridae 793 38.18 Diabrotica undecimpunctata 110 5.30 Curculionidae 90 4.33 Lepidoptera 86 4.14 Alticini 75 3.61 Cydnidae 55 2.65 Scarabaeidae 22 1.06 Acrididae 13 0.63 Chrysomelidae 10 0.48 Thysan optera 10 0.48 Aphidae 4 0.19 Membracoidea 3 0.14 Anasa tristis 2 0.10 Pentatomidae 1 0.05 Elateridae 1 0.05 Total 2077 100.00 Natural Enemies Coccinellidae 103 21.50 Orius spp. 87 18.16 Chrysopidae 69 14.41 Parasitica 66 13.78 Staphylinida e 53 11.06 Cantharidae 46 9.60 Geocoridae 14 2.92 Nabidae 14 2.92 Carabidae 6 1.25 Podisus maculiventrus 5 1.04 Araneae 9 1.88 Lampyridae 2 0.42 Salticidae 2 0.42 Formicidae 1 0.21 Reduviidae 1 0.21 Berytidae 1 0.21 Total 479 100.00 Pollinator s Syrphidae 76 66.67 Apis mellifera 26 22.81 Other Anthophilia 10 8.77 65 Bombus impatiens 2 1.75 114 100.00 b. 2015 Total insects per 20m flower transect Freq (%) Herbivores Membracoidea 610 37.70 Lygus lineolaris 453 28.00 Altic ini 152 9.39 Anthicidae 105 6.49 Cuculionidae 101 6.24 Aphididae 58 3.58 Chrysopidae 47 2.90 Chyrsomelidae 25 1.55 Miridae 22 1.36 Cydnidae 18 1.11 Lepidoptera 14 0.87 Acalymma vittatum 4 0.25 Orthoptera 8 0.49 Scarabaeidae 1 0.06 Total 1618 10 0.00 Natural Enemies Orius spp. 1677 48.38 Parasitica 1285 37.07 Coccinellidae 255 7.36 Cantharidae 132 3.81 Araneae 45 1.30 Nabidae 23 0.66 Formicidae 19 0.55 Geocoridae 12 0.35 Vespidae 9 0.26 Berytidae 2 0.06 Lampyridae 2 0.06 Elaterida e 2 0.06 Carabidae 1 0.03 Reduviidae 1 0.03 Staphylinidae 1 0.03 Total 3466 100.00 Pollinators Apis mellifera 120 50.63 Syrphidae 79 33.33 Other Apoidea 37 15.61 Bombus impatiens 1 0.42 Table S.2 . 66 Total 237 100.00 Table S.2 . 67 Table S.3 . Total arthropods captured in weekly pitfall traps in 2014 (a) and 2015 (b) . a. 2014 Total captured Freq (%) Herbivores Collembola 7,570 59.71% Aphididae 1,218 9.61% Membracoidea 1,054 8.31% Cydnidae 472 3.72% Orthoptera 468 3.69% Anthicidae 442 3.49% Thysanoptera 315 2.48% Miridae 250 1.97% Scarabaeidae 230 1.81% Chrysomelidae 157 1.24% Elateridae 89 0.70% Curculionidae 69 0.54% Anasa tristis 66 0.52% Alticini 48 0.38% Lepidoptera 44 0.35% Leptinotarsi decemlineata 39 0.31% Acalymma vittatum 39 0.31% Ly gus lineolaris 38 0.30% Histeridae 28 0.22% Pentatomidae 20 0.16% Diplopoda 10 0.08% Pentatomidae 6 0.05% Lygaeidae 4 0.03% Diabrotica undecimpunctata 2 0.02% Total 12,678 100.00% Natural Enemies Formicidae 3,357 26.33% Staphylinidae 3,122 24 .48% Carabidae 1,242 9.74% Chrysopidae 1,122 8.80% Parasitica 937 7.35% Lycosidae 832 6.52% Chilopodae 544 4.27% Other Aranea 342 2.68% Lycosidae 315 2.47% Opiliones 274 2.15% Geocoridae 243 1.91% Coccinellidae 223 1.75% Nabidae 67 0.53% Pomp ilidae 62 0.49% 68 Anthocoridae 20 0.16% Mutilidae 19 0.15% Vespidae 18 0.14% Lampyridae 4 0.03% Reduviidae 3 0.02% Cantharidae 2 0.02% Myrmeleontidae 2 0.02% Asilidae 1 0.01% Total 12,751 100.00% Other Arthropods Unknown Larva 525 56.88% Unkn own Coleoptera 174 18.85% Unknown Hymenoptera 72 7.80% Apoidea 41 4.44% Psocoptera 22 2.38% Isopoda 20 2.17% Haclictidae 16 1.73% Apis mellifera 11 1.19% Syrphidae 9 0.98% Unknown Hemiptera 9 0.98% Bombus 6 0.65% Tipuloidea 3 0.33% Sphecidae 3 0 .33% Meloidae 3 0.33% Symphyta 2 0.22% Eucerini 2 0.22% Tenthredinidae 2 0.22% Dermaptera 1 0.11% Peponapis pruinosa 1 0.11% Silphidae 1 0.11% Total 923 100.00% Table S. 3 . 69 Table S.4 . Major field activities in 2014 and 2015. The study took place in a c onventionally managed cucumber field in Benton Harbor, MI. Field Operation Year 2014 2015 Dual Magnum and Command 3ME applied 15 - Apr 16 - Apr Beds made 25 - Apr 27 - Apr Cucumbers and flowers planted 26 - Apr 30 - Apr Presidio and Admire application 30 - Ap r Dual Magnum and Command 3ME applied 30 - Apr Plastic opened on cover crops 29 - May Plastic removed 8 - Jun Harvesting begins 29 - Jun 8 - Jul Hand weeding of flower strips 2 - Jun Dual Magnum and Command 3ME applied 28 - Apr Initiate 720 and Nu - cop 50 DF applied 18 - Jun 25 - May Mancozeb applied 11 - Jun Nu Cop 50 DF, Initiate 720, Perm - up applied 18 - Jun Mancozeb applied 2 - Jul Zampro and Initiate 720 applied 4 - Aug Table S.5. Total arthropods captured by sweep net in 2014 (a) and 2015 (b). a. 2014 Total insects per 20m flower transect Freq (%) Herbivores Lygus lineolaris 802 38.61 Miridae 793 38.18 Diabrotica undecimpunctata 110 5.30 Curculionidae 90 4.33 Lepidoptera 86 4.14 Alticini 75 3.61 Cydnidae 55 2.65 Scarabaeidae 22 1.06 Acrididae 13 0.63 Chrysomelidae 10 0.48 70 Thysanoptera 10 0.48 Aphidae 4 0.19 Membracoidea 3 0.14 Anasa tristis 2 0.10 Pentatomidae 1 0.05 Elateridae 1 0.05 Total 2077 100.00 Natural Enemies Coccinellidae 103 21.50 Orius spp. 87 18.16 Chryso pidae 69 14.41 Parasitica 66 13.78 Staphylinidae 53 11.06 Cantharidae 46 9.60 Geocoridae 14 2.92 Nabidae 14 2.92 Carabidae 6 1.25 Podisus maculiventrus 5 1.04 Araneae 9 1.88 Lampyridae 2 0.42 Salticidae 2 0.42 Formicidae 1 0.21 Reduviidae 1 0.2 1 Berytidae 1 0.21 Total 479 100.00 Pollinators Syrphidae 76 66.67 Apis mellifera 26 22.81 Other Anthophilia 10 8.77 Bombus impatiens 2 1.75 114 100.00 b. 2015 Total insects per 20m flower transect Freq (%) Herbivores Membracoide a 610 37.70 Lygus lineolaris 453 28.00 Alticini 152 9.39 Anthicidae 105 6.49 Cuculionidae 101 6.24 Aphididae 58 3.58 Chrysopidae 47 2.90 T able S.5 . 71 Chyrsomelidae 25 1.55 Miridae 22 1.36 Cydnidae 18 1.11 Lepidoptera 14 0.87 Acalymma vittatum 4 0.25 Ortho ptera 8 0.49 Scarabaeidae 1 0.06 Total 1618 100.00 Natural Enemies Orius spp. 1677 48.38 Parasitica 1285 37.07 Coccinellidae 255 7.36 Cantharidae 132 3.81 Araneae 45 1.30 Nabidae 23 0.66 Formicidae 19 0.55 Geocoridae 12 0.35 Vespidae 9 0.26 Berytidae 2 0.06 Lampyridae 2 0.06 Elateridae 2 0.06 Carabidae 1 0.03 Reduviidae 1 0.03 Staphylinidae 1 0.03 Total 3466 100.00 Pollinators Apis mellifera 120 50.63 Syrphidae 79 33.33 Other Apoidea 37 15.61 Bombus impatiens 1 0.42 Total 23 7 100.00 T able S.5 . 72 Table S.6. Total arthropods captured on sticky traps in 2014 (a) and 2015 (b). a. 2014 Location Total Freq (%) Flower strip Cucumbers Herbivores Membracoidea 419 n/a 419 27.97 Lygus lineolaris 347 n/a 347 23.16 Chrysomeli dae 288 n/a 288 19.23 Alticini 170 n/a 170 11.35 Aphididae 96 n/a 96 6.41 Miridae 72 n/a 72 4.81 Cydnidae 36 n/a 36 2.40 Curculionidae 24 n/a 24 1.60 Diabrotica undecimpunctata 16 n/a 16 1.07 Acalymma vittatum 11 n/a 11 0.73 Acari 7 n/a 7 0.47 Lep idoptera 6 n/a 6 0.40 Scarabaeidae 5 n/a 5 0.33 Pentatomidae 1 n/a 1 0.07 Total 1,498 100.00 Natural Enemies Orius spp. 471 n/a 471 40.19 Parasitica 401 n/a 401 34.22 Coccinellidae 79 n/a 79 6.74 Staphylinidae 57 n/a 57 4.86 Araneae 46 n/a 46 3.92 Chrysopidae 34 n/a 34 2.90 Rove Beetle 26 n/a 26 2.22 Cantharidae 26 n/a 26 2.22 Carabidae 18 n/a 18 1.54 Geocoridae 5 n/a 5 0.43 Elateridae 4 n/a 4 0.34 Nabidae 3 n/a 3 0.26 Formicidae 1 n/a 1 0.09 Reduviidae 1 n/a 1 0.09 Total 1,172 100.00 Pollinators Apis mellifera 0 n/a 0 0.00 Bombus impatiens 1 n/a 1 0.79 Peponapis pruinosa 0 n/a 0 0.00 Syrphidae 15 n/a 15 11.90 Other Apoidea 110 n/a 110 87.30 Total 126 100.00 73 b. 2015 Location Total Freq (%) Flower strip Cucumbers Herbivores Membracoidea 610 591 1,201 39.35 Lygus lineolaris 453 412 865 28.34 Alticini 152 96 248 8.13 Anthicidae 105 94 199 6.52 Cuculionidae 101 95 196 6.42 Aphididae 58 72 130 4.26 Chrysopidae 47 5 52 1.70 Chyrsomelid ae 25 16 41 1.34 Miridae 22 14 36 1.18 Cydnidae 18 12 30 0.98 Lepidoptera 14 6 20 0.66 Acalymma vittatum 4 14 18 0.59 Orthoptera 8 6 14 0.46 Scarabaeidae 1 1 2 0.07 Total 3,052 100.00 Natural Enemies Parasitica 898 779 1,677 48.41 Ori us spp. 931 354 1,285 37.10 Araneae 88 167 255 7.36 Coccinellidae 71 61 132 3.81 staphylinidae 18 27 45 1.30 Cantharidae 20 3 23 0.66 Nabidae 10 9 19 0.55 Formicidae 4 8 12 0.35 Elateridae 3 6 9 0.26 Hemerobiade 2 0 2 0.06 Lampyridae 1 1 2 0.06 G eocoridae 1 1 2 0.06 Berytidae 0 1 1 0.03 Total 3,464 100.00 Pollinators Apis mellifera 4 6 10 7.35 Bombus impatiens 0 0 0 0.00 Peponapis pruinosa 0 0 0 0.00 Syrphidae 66 37 103 75.74 Other Apoidea 16 7 23 16.91 Total 136 100.00 T able S.6 . 74 Table S.7. Total pollinators observed in 2014 (a) and 2015 (b). a. 2014 Row Total % 0 1 3 5 Apis mellifera n/a 45 40 46 131 24.76 Bombus impatiens n/a 3 2 2 7 1.32 Peponapis pruinosa n/a 110 99 122 331 62.57 Syrphidae n/a 27 26 53 10.02 Othe r Apoidea n/a 0 7 0 7 1.32 Total n/a 185 174 170 529 100.00 b. 2015 Row Total % 0 1 3 5 Apis mellifera 2488 266 173 178 3105 61.27 Bombus impatiens 0 0 0 0 0 0.00 Peponapis pruinosa 4 3 4 5 16 0.32 Syrphidae 1738 75 22 15 1850 36.50 Other A poidea 80 8 3 6 97 1.91 Total 4310 352 202 204 5068 100.00 75 APPENDIX B: Record of Deposition of Voucher Specimens The specimens listed below have been deposited in the named museum as samples of those species or other taxa, which were used in th is research. Voucher recognition labels bearing the voucher number have been attached or included in fluid preserved specimens. Voucher Number: 2015 - 05 . Author and Title of thesis: Author: Nicole F. Quinn Title: Habitat Management for Benefic ial Insects in Michigan Cucurbit Agroecosystems Museum(s) where deposited: Albert J. Cook Arthropod Research Collection, Michigan State University (MSU) Specimens: **If lowest taxonomic level is above family, lowest classification used for arthropod is indicated Table S.8. Voucher specimens deposited at the Albert J. Cook Arthropod Research Collection (Michigan State University). Family Genus - Species Life Stage Quantity Preservation Acrididae Adult 2 pinned Anthicidae Adult 2 pinned Alticini Adult 2 pinned Andrenidae Andrena wilkella Adult 2 pinned Anthocoridae Orius spp. Adult 2 pinned Aphididae Adult 1 pinned Apidae Apis mellifera Adult 2 pinned Apidae Bombus spp. Adult 2 pinned Apidae Peponapis pruinosa Adult 2 pinned Beryti dae Adult 1 pinned Carabidae Agonum spp. Adult 2 pinned Carabidae Amara spp. Adult 2 pinned Carabidae Anisodactylus spp. Adult 2 pinned Carabidae Bembidion spp. Adult 2 pinned Carabidae Calosoma spp. Adult 1 pinned Carabidae Cicindellinae spp . Adult 2 pinned 76 Carabidae Geopinus incrassatus Adult 2 pinned Carabidae Harpalus spp. Adult 2 pinned Carabidae Pterostichus spp. Adult 2 pinned Carabidae Stenolophus spp. Adult 2 pinned Chrysomelidae Acalymma vittatum Adult 2 pinned Chrysopida e Adult 1 pinned Cicadellidae Adult 2 pinned Coccinellidae Adult 4 pinned Coreidae Anasa tristis Adult 2 pinned Curculionidae Adult 2 pinned Cydnidae Adult 2 pinned Formicidae Adult 2 pinned Geocoridae Adult 2 pinned Gryllidae Adul t 2 pinned Halictidae Lasioglossum spp. Adult 2 pinned Ichneumonidae Adult 2 pinned Miridae Lygus lineolaris Adult 2 pinned Mutilidae Adult 2 pinned Nabidae Adult 2 pinned Pentatomidae Adult 2 pinned Reduviidae Adult 2 pinned Scarabaeid ae Adult 2 pinned Staphylinidae Adult 2 pinned Syrphidae Adult 2 pinned T able S. 8 . 77 LITERATURE CITED 78 LITER ATURE CITED Abawi, G., and T. Widmer . 2000 . Impact of soil health management practices on soilborne pathogens, nematodes and root diseases of vegetable crops. Appl. Soil Ecol. 15: 37 47. Abd - Rabou, S. 2014 . Parasitoids as a bioagent to eliminate the insecticides to control the main pests - infested economic crops. Arch. Phytopathol. Plant Prot. 47: 2157 2175. Agrawal, A. A. A. Janssen, J. Bruin, M. a. Posthumus, and M. W. Sabelis . 2002 . An ecological cost of plant defence: Attractiveness of bitter cucumber plants to natural enemies of herbivores. Ecol. Lett. 5: 377 385. Andow, D. A. 1991 . Vegetational diversity and arthropod population response. Annu. Rev. Entomol. 36: 561 586. Andrews, E. S., N. Theis, and L. S. Adler . 2007 . Pollinat or and Herbivore Attraction to C ucurbita Floral Volatiles. J. Chem. Ecol. 33: 1682 91. Anjum - Zubair, M., M. H. Entling, A. Bruckner, T. Drapela, and T. Fran k . 2015 . Differentiation of spring carabid beetle assemblages between semi - natural habitats and adjoining winter wheat. Agric. For. Entomol. n/a n/a. J. A. Mathewson . 1968 . Nest Construction and Life History of the Eastern Cucurbit Bee , Peponapis pruinosa Entomological Society. 41: 255 261. Artz, D. R., and B. a. Nault . 2011 . Performance of Apis mellifera , Bombus impatiens, and Peponapis pruinosa (Hymenoptera: Apidae) as Pollinators of Pumpk in. J. Econ. Entomol. 104: 1153 1161. Bagavathiannan, M. V, and J. K. Norsworthy . 2013 . Postdispersal Loss of Important Arable Weed Seeds in the Midsouthern United States. Weed Sci. 61: 570 579. Baraibar, B., D. Daedlow, F. de Mol, and B. Gerowitt . 2012 . D ensity dependence of weed seed predation by invertebrates and vertebrates in winter wheat. Weed Res. 52: 79 87. Barber, N. a, L. S. Adler, and H. L. Bernardo . 2011 . Effects of above - and belowground herbivory on growth, pollination, and reproduction in cuc umber. Oecologia. 165: 377 86. Barnett, K. 2012 . Wisconsin Fresh Market Vegetable Budgets: Pumpkins. (http://cdp.wisc.edu/Freshmarket.htm). Benjamin, F. E., J. R. Reilly, and R. Winfree . 2014 . Pollinator body size mediates the scale at which land use drive s crop pollination services. J. Appl. Ecol. 51: 440 449. 79 Berndt, L. A., and S. D. Wratten . 2005 . Effects of alyssum flowers on the longevity, fecundity, and sex ratio of the leafroller parasitoid Dolichogenidea tasmanica . Biol. Control. 32: 65 69. Bhardwaj , R. K., and S. Kumar . 2014 . Studies on correlation between yield and seed characters in cucumber , Cucumis sativus L. Int. J. Farm Sci. Bianchi, F. J., C. J. Booij, and T. Tscharntke . 2006 . Sustainable pest regulation in agricultural landscapes: a review on landscape composition, biodiversity and natural pest control. Proc. R. Soc. London Ser. B. 273: 1715 1727. Birkhofer, K., F. Arvidsson, D. Ehlers, V. L. Mader, J. Bengtsson, and H. G. Smith . 2015 . Organic farming affects the biological control of hemipt eran pests and yields in spring barley independent of landscape complexity. Landsc. Ecol. Birthisel, S. K., E. R. Gallandt, and R. Jabbour . 2014 . Habitat effects on second - order predation of the seed predator Harpalus rufipes and implications for weed seed bank management. Biol. Control. 70: 65 72. Blaauw, B. R., and R. Isaacs . 2014 . Flower plantings increase wild bee abundance and the pollination services provided to a pollination - dependent crop. J. Appl. Ecol. 51: 890 898. Blubaugh, C. K., and I. Kaplan . 2 015 . Tillage compromises weed seed predator activity across developmental stages. Biol. Control. 76 82. Booman, G. C., P. Laterra, V. Comparatore, and N. Murillo . 2009 . Post - dispersal predation of weed seeds by small vertebrates: Interactive influences of neighbor land use and local environment. Agric. Ecosyst. Environ. 129: 277 285. Bottrell, D. G., P. Barbosa, and F. Gould . 1998 . Manipulating natural enemies by plant variety selection and modification: a realistic strategy? Annu. Rev. Entomol. 43: 347 367 . Bourassa, S., H. A. Cárcamo, F. J. Larney, and J. R. Spence . 2008 . Carabid Assemblages (Coleoptera: Carabidae) in a Rotation of Three Different Crops in Southern Alberta, Canada: A Comparison of Sustainable and Conventional Farming. Environ. Entomol. 37: 1214 1223. Bousquet, Yves. 2010. Illustrated identification guide to adults and larvae of northeastern North American ground beetles (Coleoptera : Carabidae) . Brainard, D. C., R. E. Peachey, E. R. Haramoto, J. M. Luna, and A. Rangarajan . 2013 . Weed Ecology and Nonchemical Management under Strip - Tillage: Implications for Northern U.S. Vegetable Cropping Systems. Weed Technol. 27: 218 230. 80 Brittain, C., N. Williams, C. Kremen, and A. - M. Klein . 2013 . Synergistic effects of non - Apis bees and honey bees for poll ination services. Proc. Biol. Sci. 280: 20122767. Brown, J. E., J. M. Dangler, F. M. Woods, K.M. Tilt, M.D. Henshaw, W.A . Griffey, and M. S. West . 1993 . Delay in Mosaic Virus Onset and Aphid Vector Reduction in Summer Squash Grown on Reflective Mulches. Ho rtScience. 28: 895 896. Brown, P. M. J., B. Ingels, A. Wheatley, E. L. Rhule, P. de Clercq, T. van Leeuwen, and A. Thomas . 2015 . Intraguild predation by Harmonia axyridis (Coleoptera: Coccinellidae) on native insects in Europe: molecular detection from fie ld samples. Entomol. Sci. 130 133. Bryant, A., D. C. Brainard, E. R. Haramoto, and Z. Szendrei . 2013 . Cover crop mulch and weed management influence arthropod communities in strip - tilled cabbage. Environ. Entomol. 42: 293 306. Bryant, A., T. Coudron, D. Br ainard, and Z. Szendrei . 2014 . Cover crop mulches influence biological control of the imported cabbageworm (Pieris rapae L., Lepidoptera: Pieridae) in cabbage. Biol. Control. 73: 75 83. Cane, J. H., B. J. Sampson, and S. A. Miller . 2011 . Pollination value of male bees: the specialist bee Peponapis pruinosa (Apidae) at summer squash (Cucurbita pepo). Environ. Entomol. 40: 614 20. Canto - aguilar, A., and M. Veterinaria . 2000 assessing the pollination efficiency of the squash bee , Peponapis limitaris in Cucurbita moschata (Cucurbitaceae). J. Insect Conserv. 4: 203 210. Cardina, J., H. M. Norquay, B. R. Stinner, and D. A. Mcc artney . 2014 . Weed Science Society of America Postdispersal Predation of Velvetleaf ( Abutilon theophrasti ) Seeds. Weed Sci. 44: 534 539. Cardoza, Y. J., G. K. Harris, and C. M. Grozinger . 2012 . Effects of Soil Quality Enhancement on Pollinator - Plant Intera ctions. Psyche A J. Entomol. 2012: 1 8. Carmona, D. M., and D. A. Landis . 1999 . Influence of Refuge Habitats and Cover Crops on Seasonal Activity - Control. 28: 1145 1153. Chaplin - . 2011 . A meta - analysis of crop pest and natural enemy response to landscape complexity. Ecol. Lett. 14: 922 32. Chauhan, B. S., R. G. Singh, and G. Mahajan . 2012 . Ecology and management of weeds under conservation agriculture: A review. Crop Prot. 38: 57 65. 81 Clark, M. S., S.H.Gage , and J.R.Spence . 1997 . Habitats and management associated with common ground beetles (Coleoptera: Carabidae) in a Michigan Agricultural Landscape. Environ. Entomol. Cnaani, J., J. D. Thomson, and D. R. Papaj . 2006 . Flower Choice and Learning in Foraging B umble bees: Effects of Variation in Nectar Volume and Concentration. Ethology. 112: 278 285. Collevatti, R. G., L.O. Campos, and J. H. Schoereder . 1997 . Foraging behaviour of bee pollinators on the tropical weed Triumfetta semitriloba flower patches. Insectes Soc. 44: 345 352. Cook, S. M., C. S. Awmack, D. A. Murray, and I. H. Williams . 2003 foraging preferences affected by pollen amino acid composition? Ecol. Entomol. 28: 622 627. Corbett, A., and J. a. Rosenheim . 199 6 . Impact of a natural enemy overwintering refuge and its interaction with the surrounding landscape. Ecol. Entomol. 21: 155 164. Costello, M., and M. Altieri . 1995 . Abundance, growth rate and parasitism of Brevicoryne brassicae and Myzus persicae(Homopter a: Aphididae) on broccoli grown in living mulches. Agric. Ecosyst. Environ. Cromar, H. E., S. D. Murphy, and C. J. Swanton . 1999 . Influence of tillage and crop residue on postdispersal predation of weed seeds. Weed Sci. 47: 184 194. Crowder, D. W., and R. Jabbour . 2014 . Relationships between biodiversity and biological control in agroecosystems: Current status and future challenges. Biol. Control. 75: 8 17. Danner, N., S. Härtel, and I. Steffan - Dewenter . 2014 . Maize pollen foraging by honey bees in relation to crop area and landscape context. Basic Appl. Ecol. 15: 677 684. Decker, K. B., and K. V Yeargan . 2008 . Seasonal phenology and natural enemies of the squash bug (Hemiptera: Coreidae) in Kentucky. Environ. Entomol. 37: 670 678. Duelli, P., M. K. Obrist, and D. R. Schmatz . 1999 . Biodiversity evaluation in agricultural landscapes: Above - ground insects. Agric. Ecosyst. Environ. 74: 33 64. Duru, M., O. Therond, G. Martin, R. Martin - Clouaire, M. - A. Magne, E. Justes, E. - P. Journet, J. - N. Aubertot, S. Savary, J. - E. Bergez, and J. P. Sarthou . 2015 . How to implement biodiversity - based agriculture to enhance ecosystem services: a review. Agron. Sustain. Dev. Easton, A. H., and D. Goulson . 2013 . The neonicotinoid insecticide imidacloprid repels pollinating flies and beetles at field - realistic concentrations. PLoS One. 8: e54819. 82 Eyre, M. D., M. L. Luff, and C. Leifert . 2013 . Crop, field boundary, productivity and disturbance influences on ground beetles (Coleoptera, Carabidae) in the agroecosystem. Agric. Ecosyst. Env iron. 165: 60 67. Fiedler, A. K., D. a. Landis, and S. D. Wratten . 2008 . Maximizing ecosystem services from conservation biological control: The role of habitat management. Biol. Control. 45: 254 271. Finch, S., and R. H. Collier . 2000 . Host - plant selectio n by insects - a theory based on Appl. 96: 91 102. Forrest, J. R. K., R. W. Thorp, C. Kremen, and N. M. Williams . 2015 . Contrasting patterns in species and functional - trait diversity of bees in an agricult ural landscape. J. Appl. Ecol. Fournier, A., O. Rollin, V. Le Féon, A. Decourtye, and M. Henry . 2014 . Crop - emptying rate and the design of pesticide risk assessment schemes in the honey bee and wild bees (Hymenoptera: Apidae). J. Econ. Entomol. 107: 38 46. Gajc - Wolska, J., K. Kowalczyk, J. Mikas, and R. Drajski . 2011 . Efficiency o f Cucumber ( Cucumis sativus L. ) Pollination b y Bumble Bees ( Bombus terrestris ). Acta Sci. Pol., Hortorum Cultus. 10: 159 169. García, R. R., and M. Minarro . 2014 . Role of floral resources in the conservation of pollinator communities in cider - apple orchards. Agric., Ecosyst. Environ. 183: 118 126. Garibaldi, L.A. , I. Steffan - Dewenter, R. Winfree, M. a Aizen, R. Bommarco, S. A. Cunningham, C. Kre men, L. G. Carvalheiro, L. D. Harder, O. Afik, I. Bartomeus, F. Benjamin, V. Boreux, D. Cariveau, N. P. Chacoff, J. H. Dudenhöffer, B. M. Freitas, J. Ghazoul, S. Greenleaf, J. Hipólito, A. Holzschuh, B. Howlett, R. Isaacs, S. K. Javorek, C. M. Kennedy, K. M. Krewenka, S. Krishnan, Y. Mandelik, M. M. Mayfield, I. Motzke, T. Munyuli, B. a Nault, M. Otieno, J. Petersen, G. Pisanty, S. G. Potts, R. Rader, T. H. Ricketts, M. Rundlöf, C. L. Seymour, C. Schüepp, H. Szentgyörgyi, H. Taki, T. Tscharntke, C. H. Verga ra, B. F. Viana, T. C. Wanger, C. Westphal, N. Williams, and A. M. Klein . 2013 . Wild pollinators enhance fruit set of crops regardless of hon ey bee abundance. Science (80 ). 339: 1608 11. Garibaldi, L. A., L. G. Carvalheiro, S. D. Leonhardt, M. a Aizen, B. R. Blaauw, R. Isaacs, M. Kuhlmann, D. Kleijn, A. M. Klein, C. Kremen, L. Morandin, J. Scheper, and R. Winfree . 2014 . From research to action: practices to enhance crop yield through wild pollinators. Front. Ecol. Environ (12). 8: 439 - 447 Garibaldi, L. A., I. Steffan - Dewenter, C. Kremen, J. M. Morales, R. Bommarco, S. A. Cunningham, L. G. Carvalheiro, N. P. Chacoff, J. H. Dudenhöffer, S. S. Greenleaf, A. Holzschuh, R. Isaacs, K. Krewenka, Y. Mandelik, M. M. Mayfield, L. A. Morandin, S. 83 G. Potts, T. H. Ricke tts, H. Szentgyörgyi, B. F. Viana, C. Westphal, R. Winfree, and A. M. Klein . 2011 . Stability of pollination services decreases with isolation from natural areas despite honey bee visits. Ecol. Lett. 14: 1062 72. Geib, J. C., J. P. Strange, and C. Galen . 20 15 . Bumble bee nest abundance, foraging distance, and host - plant reproduction: implications for management and conservation. Ecol. Appl. 25. Giannini, T. C., L. A. Garibaldi, A. L. Acosta, J. S. Silva, K. P. Maia, A. M. Saraiva, P. R. Guimarães, and A. M. P. Kleinert. 2015. Native and Non - Native Supergeneralist Bee Species Have Different Effects on Plant - Bee Networks. PLoS One. 10: e0137198. Gingras, D., J. Gingras, and D. De Oliveira . 1999 Apidae) and their Effects on C ucumber Yields in the Field. Hortic. Entomol. 92: 435 438. Goulson, D., E. Nicholls, C. Botias, and E. L. Rotheray . 2015 . Bee declines driven by combined stress from parasites, pesticides, and lack of flowers. Science (80 - . ). 347. Grasswitz, T. R. 2013 . D evelopment of an Insectary Plant Mixture for New Mexico and its Effect on Pests and Beneficial Insects Associated with Pumpkins. Southwest. Entomol. 38: 417 436. . 1971 . The use of baits and preservatives in pitfall traps. J. Aust. Entomol. Soc. 10: 253 260. Greenleaf, S. S., and C. Kremen . 2006 . Wild bee species increase tomato prod uction and respond differently to surrounding land use in Northern California. Biol. Conserv. 133: 81 87. Greenleaf, S. S., N. M. Williams, R. Winfree, and C. Kremen . 2007 . Bee foraging ranges and their relationship to body size. Oecologia. 153: 589 96. Gr iffiths, G. J. K., J. M. Holland, A. Bailey, and M. B. Thomas . 2008 . Efficacy and economics of shelter habitats for conservation biological control. Biol. Control. 45: 200 209. Hans P etersen, H. N., R. Mcsorley, and O. E. Liburd . 2010 . The Impact of Intercr opping Squash with Non - Crop Vegetation Borders on the Above - Ground Arthropod Community Borders on the Above - Ground Arthropod Community. Florida Entomol. 93: 590 608. Hatchett, J. H., R. D. Jackson, and R. M. Barry . 1973 . Rearing a Weed Cerambycid, Dectes t exanus, on an Artificial Medium, with Notes on Biology. Ann. Entomol. Soc. Am. 66: 519 522. Hinds, J., and C. R. R. Hooks . 2013 . Population dynamics of arthropods in a sunn - hemp zucchini interplanting system. Crop Prot. 53: 6 12. 84 Hladun, K. R., and L. S. A dler . 2009 . Influence of leaf herbivory, root herbivory, and pollination on plant performance in Cucurbita moschata . Ecol. Entomol. 34: 144 152. Holland, J. M., B. M. Smith, J. Storkey, P. J. W. Lutman, and N. J. Aebischer . 2015 . Managing habitats on Engli sh farmland for insect pollinator conservation. Biol. Conserv. 182: 215 222. Holzschuh, A., J. H. Dudenhöffer, and T. Tscharntke . 2012 . Landscapes with wild bee habitats enhance pollination, fruit set and yield of sweet cherry. Biol. Conserv. 153: 101 107. Honek, A., Z. Martinkova, and V. Jaorsik . 2003 . Ground beetles (Carabidae) as seed predators. Eur. J. Entomol. 231 544. Hooks, C. R. ., J. Hinds, E. Zobel, and T. Patton . 2013 . The effects of crimson clover companion planting on eggplant crop growth, yield and insect feeding injury. Int. J. Pest Manag. 59: 287 293. Hooks, C. R. ., H. . Valenzuela, and J. Defrank . 1998 . Incidence of pests and arthropod natural enemies in zucchini grown with living mulches. Agric. Ecosyst. Environ. 69: 217 231. Hooks, C. R., and M. W. Johnson . 2004 . Using undersown clovers as living mulches: effects on yields, lepidopterous pest infestations, and spider densities in a Hawaiian broccoli agroecosystem. Int. J. Pest Manag. 50: 115 120. Hooks, C. R., R. R. Pandey, and M. W. Johnso n . 2007 . Using Clovers as Living Mulches To Boost Yields, Suppress Pests, and Augment Spiders in a Broccoli Agroecosystem. Insect Pests. Hudewenz, A., and A. - M. Klein . 2013 . Competition between honey bees and wild bees and the role of nesting resources in a nature reserve. J. Insect Conserv. 17: 1275 1283. Hummel, R. L., J. F. Walgenbach, G. D. Hoyt, and G. G. Kennedy . 2002 . Effects of production system on vegetable arthropods and their natural enemies. Agric. Ecosyst. Environ. 93: 165 176. Hurd, P. D. J., E. G. L. Whitaker, and T. W. Whitaker . 2013 . Squash and Gourd Bees ( Peponapis , Xenoglossa) and the Origin of the Cultivated Cucurbita. Evolution (N. Y). 25: 218 234. Hurd, P. D., E. G. Linsley, and A. E. Michelbacher . 1974 . Ecology of the Squash and Gourd Bee , Peponapis pruinosa Smithson. Inst. Press. 85 Isaacs, R., J. Tuell, A. Fiedler, M. Gardiner, and D. Landis . 2009 . Maximizing arthropod - mediated ecosystem services in agricultural landscape s: the role of native plants. Front. Ecol. Environ. 7: 196 203. Ismail, S. M., and K. Ozawa . 2007 . Improvement of crop yield, soil moisture distribution and water use efficiency in sandy soils by clay application. Appl. Clay Sci. 37: 81 89. Iverson, A. L., L. E. Marin, K. K. Ennis, D. J. Gonthier, B. T. Connor - Barrie, J. L. Remfert, B. J. Cardinale, and I. Perfecto . 2014 . Do polycultures promote win - wins or trade - offs in agricultural ecosystem services? A meta - analysis. J. Appl. Ecol. 51: 1593 1602. Ivey, C . T., P. Martinez, and R. Wyatt . 2003 . Variation in pollinator effectiveness in swamp milkweed, Asclepias incarnata (Apocynaceae). Am. J. Bot. 90: 214 225. Jakobsson, A., and J. Ågren . 2014 . Distance to semi - natural grassland influences seed production of insect - pollinated herbs. Oecologia. 175: 199 208. Joshi, N. K., T. Leslie, E. G. Rajotte, M. A. Kammerer, M. Otieno, and D. J. Biddinger . 2015 . Comparative Trapping Efficiency to Characterize Bee Abundance, Diversity, and Community Composition in Apple Orc hards. Ann. Entomol. Soc. Am. sav057. Julier, H. E., and T. A. H. Roulston . 2009a . Wild Bee Abundance and Pollination Service in Bee Abundance and Pollination Service in Cu Nesting Behavior and Landscape Effects. J. Econ. Entomol. 102: 563 573. Julier, H. E., and T. H. Roulston . 2009b . Wild bee abundance and pollination service in cultivated pumpkins: farm management, nesting behavior and landscape effects. J. Econ. Entomol. 102: 563 73. Kaddi, G., B. S. Tomar, and B. Singh . 2015 . Effect of pollination time on fruit set and seed yield in hybrid seed production of cucumber ( Cucumis sativus ) cv. Pant Shankar Khira 1 under different growing c onditions. INDIAN J. Agric. Sci. 85: 725 729. Kappers, I. F., H. Hoogerbrugge, H. J. Bouwmeester, and M. Dicke . 2011 . Variation in Herbivory - induced Volatiles Among Cucumber ( Cucumis sativus L.) Varieties has Consequences for the Attraction of Carnivorous Natural Enemies. J. Chem. Ecol. 37: 150 160. Kennedy, C. M., E. Lonsdorf, M. C. Neel, N. M. Williams, T. H. Ricketts, R. Winfree, R. Bommarco, C. Brittain, A. L. Burley, D. Cariveau, L. G. Carvalheiro, N. P. Chacoff, S. a Cunningham, B. N. Danforth, J. - H. Dudenhöffer, E. Elle, H. R. Gaines, L. a Garibaldi, C. Gratton, A. Holzschuh, R. Isaacs, S. K. Javorek, S. Jha, A. M. Klein, K. Krewenka, Y. Mandelik, M. M. Mayfield, L. Morandin, L. a Neame, M. Otieno, M. 86 Park, S. G. Potts, M. Rundlöf, A. Saez, I. Steffan - Dewenter, H. Taki, B. F. Viana, C. Westphal, J. K. Wilson, S. S. Greenleaf, and C. Kremen . 2013 . A global quantitative synthesis of local and landscape effects on wild bee pollinators in agroecosystems. Ecol. Lett. 16. Kirk, V. M. 1972 . Seed - Caching by La rvae of Two Ground Beetles , Harpalus pensylvanicus and H. erraticus . Ann. Entomol. Soc. Am. 65: 1426 1428. Kirk, V. M. 1974 . Biology of a ground beetle, Harpalus erraticus . Ann. Entomol. Soc. Am. 67: 24 28. Kleijn, D., R. Winfree, I. Bartomeus, L. G. Carva lheiro, M. Henry, R. Isaacs, A. - M. Klein, Adamson, J. S. Ascher, A. Báldi, P. Batáry, F. Benjamin, J. C. Biesmeijer, E. J. Blitzer, R. Bommarco, M. R. Brand, V. Bretagnolle, L. Bu tton, D. P. Cariveau, R. Chifflet, J. F. Colville, B. N. Danforth, E. Elle, M. P. D. Garratt, F. Herzog, A. Holzschuh, B. G. Howlett, F. Jauker, S. Jha, E. Knop, K. M. Krewenka, V. Le Féon, Y. Mandelik, E. A. May, M. G. Park, G. Pisanty, M. Reemer, V. Ried inger, O. Rollin, M. Rundlöf, H. S. Sardiñas, J. Scheper, A. R. Sciligo, H. G. Smith, I. Steffan - Dewenter, R. Thorp, T. Tscharntke, J. Verhulst, B. F. Viana, B. E. Vaissière, R. Veldtman, C. Westphal, and S. G. Potts . 2015 . Delivery of crop pollination ser vices is an insufficient argument for wild pollinator conservation. Nat. Commun. 6: 7414. Klein, A. - M., B. E. Vaissière, J. H. Cane, I. Steffan - Dewenter, S. a Cunningham, C. Kremen, and T. Tscharntke . 2007 . Importance of pollinators in changing landscapes for world crops. Proc. Biol. Sci. 274: 303 313. Kremen, C., A. Iles, and C. Bacon . 2012 Systems - based Alternative to Modern Industrial Agriculture. Ecol. Soc. 17. Kremen, C., and A. Miles . 2012 . Ecosystem S ervices in Biologically Diversified versus Conventional Farming Systems: Benefits, Externalities, and Trade - Offs. Ecol. Soc. 17. Kromp, B. 1989 . Carabid beetle communities (Carabidae, coleoptera) in biologically and conventionally farmed agroecosystems. Ag ric. Ecosyst. Environ. 27: 241 251. Kromp, B. 1999 . Carabid beetles in sustainable agriculture: A review on pest control efficacy, cultivation impacts and enhancement. Agric. Ecosyst. Environ. 74: 187 228. van der Laat, R., M. D. K. Owen, M. Liebman, and R . G. Leon . 2015 . Post - Dispersal Weed Seed Predation and Invertebrate Activity - Density in Three Tillage Regimes. Weed Sci. 150520130835007. Landis, D. A., S. D. Wratten, and G. M. Gurr . 2000 . Habitat Management to Conserve Natural Enemies of Arthropod Pests in Agriculture. Annu. Rev. Entomol. 45: 175 201. 87 Langellotto, G. A., and R. F. Denno . 2004 . Responses of invertebrate natural enemies to complex - structured habitats: a meta - analytical synthesis. Oecologia. 139: 1 10. Larson, J. L., C. T. Redmond, and D. a . Potter . 2014 . Impacts of a neonicotinoid, neonicotinoid - pyrethroid premix, and anthranilic diamide insecticide on four species of turf - inhabiting beneficial insects. Ecotoxicology. 23: 252 259. Law, J. J., and R. S. Gallagher . 2015 . The role of imbibitio n on seed selection by Harpalus pensylvanicus . Appl. Soil Ecol. 87: 118 124. Lee, J. C., F. D. Menalled, and D. a. Landis . 2001 . Refuge habitats modify impact of insecticide disturbance on carabid beetle communities. J. Appl. Ecol. 38: 472 483. van Lentere n, J. C. 2011 . The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake. BioControl. 57: 1 20. Liebman , M., and A . S. Davis . 2000 . Integration of soil, crop and weed management in low - external - inp ut farming systems. Weed Res. 40: 27 47. Long, R. F., A. Corbett, C. Lamb, C. Reberg - Horton, J. Chandler, and M. Stimmann . 1998 . Beneficial insects move from flowering plants to nearby crops. Calif. Agric. 52: 23 26. Lonsdorf, E., C. Kremen, T. Ricketts, R . Winfree, N. Williams, and S. Greenleaf . 2009 . Modelling pollination services across agricultural landscapes. Ann. Bot. 103: 1589 600. Lowenstein, D. M., a S. Huseth, and R. L. Groves . 2012 . Response of wild bees (Hymenoptera: Apoidea: Anthophila) to surr ounding land cover in Wisconsin pickling cucumber. Environ. Entomol. 41: 532 40. Luna, A. J. M., and L. Xue . 2009 . Aggregation Behavior of Western Spotted Cucumber Beetle Systems. Environ. Entomol. 38: 8 09 814. Luna, J. M., J. P. Mitchell, and A. Shrestha . 2012 . Conservation tillage for organic agriculture: Evolution toward hybrid systems in the western USA. Renew. Agric. Food Syst. 27: 21 30. Lundgren, J. G., and J. K. Fergen . 2010 . The Effects of a Wint er Cover Crop on Diabrotica virgifera (Coleoptera: Chrysomelidae) Populations and Beneficial Arthropod Communities in No - Till Maize. Environ. Entomol. 39: 1816 1828. Lundgren, J. G., and J. D. Harwood . 2012 . Functional Responses to Food Diversity: the Effe ct of Seed Availability on the Feeding Behavior of Facultative Granivores. J. Entomol. Sci. 47: 160 176. 88 Lundgren, J. G., S. Nichols, D. a. Prischmann, and M. M. Ellsbury . 2009 . Seasonal and diel activity patterns of generalist predators associated with Di abrotica virgifera immatures (Coleoptera: Chrysomelidae). Biocontrol Sci. Technol. 19: 327 333. . 2013 . Molecular approach to describing a seed - based food web: The post - dispersal granivore community of an invasive pla nt. Ecol. Evol. 3: 1642 1652. Macintyre - Allen, J. K., C. D. Scott - Dupree, J. H. Tolman, C. R. Harris, and S. A. Hilton . 2001 . Integrated pest management options for the control of Acalymma vittatum (Fabricius), the striped cucumber beetle in southwestern O ntario. Proc. Entomol. Soc. Ontario. 132: 27 38. Marino, P. C., K. L. Gross, and D. a. Landis . 1997 . Weed seed loss due to predation in Michigan maize fields. Agric. Ecosyst. Environ. 66: 189 196. Marshall, S. D., and A. L. Rypstra . 1999 . Patterns in the D istribution of Two Wolf Spiders (Araneae: Lycosidae) in Two Soybean Agroecosytems. Environ. Entomol. 28: 1052 1059. Masierowska, M. L. 2003. Floral nectaries and nectar production in brown mustard (Brassica juncea) and white mustard (Sinapis alba) (Brassic aceae). Plant Syst. Evol. 238: 97 107. McCabe, D. J., and N. J. Gotelli . 2000 . Effects of disturbance frequency, intensity, and area on assemblages of stream macroinvertebrates. Oecologia. 124: 270 279. McGregor, S. E. 1976 . Insect Pollination Of Cultivate d Crop Plants. USDA. 849. Menalled, F. D., P. C. Marino, K. a. Renner, and D. a. Landis . 2000 . Post - dispersal weed seed predation in Michigan crop fields as a function of agricultural landscape structure. Agric. Ecosyst. Environ. 77: 193 202. Mitchell, T. B. 1962 . Bees of the Eastern United States. Mitchell, M. G. E., E. M. Bennett, and A. Gonzalez . 2014 . Forest fragments modulate the provision of multiple ecosystem services. J. Appl. Ecol. 51: 909 918. Morandin, L.A ., R. F. Long, and C. Kremen . 2014 . Hedge rows enhance beneficial insects on adjacent tomato fields in an intensive agricultural landscape. Agric. Ecosyst. Environ. 189: 164 170. Morreale, S. J., and K. L. Sullivan . 2010 . Community - level enhancements of biodiversity and ecosystem services. Front. Earth Sci. China. 4: 14 21. 89 Motzke, I., T. Tscharntke, T. C. Wanger, and A. - M. Klein . 2015 . Pollination mitigates cucumber yield gaps more than pesticide and fertilizer use in tropical smallholder gardens. J. Appl. Ecol. 52: 261 269. Nicholls , C. I., and M .A . Altieri . 2012 . Plant biodiversity enhances bees and other insect pollinators in agroecosystems. A review. Agron. Sustain. Dev. 33: 257 274. Norfolk, O., M. P. Eichhorn, and F. S. Gilbert . 2015 . Contrasting patterns of turnover between plants, pollinato rs and their interactions. Divers. Distrib. 21: 405 415. . 2006 . Post - dispersal weed seed predation by invertebrates in conventional and low - external - input crop rotation systems. Agric. Ecosys t. Environ. 116: 280 288. Otieno, M., B.A . Woodcock, A. Wilby, I. N. Vogiatzakis, A. L. Mauchline, M. W. Gikungu, and S. G. Potts . 2011 . Local management and landscape drivers of pollination and biological control services in a Kenyan agro - ecosystem. Biol. Conserv. 144: 2424 2431. Park, M. G., E. J. Blitzer, J. Gibbs, J. E. Losey, B. N. Danforth, and M. G. Park . 2015 . Negative effects of pesticides on wild bee communities can be buffered by landscape context. Peng, Y.B., Y. - Q. Li, Y.J. Hao, Z.H. Xu, and S. N . Bai . 2004 . Nectar production and transportation in the nectaries of the female Cucumis sativus L. flower during anthesis. Protoplasma. 224: 71 78. Petersen, J. D., and B. a. Nault . 2014 . Landscape diversity moderates the effects of bee visitation frequen cy to flowers on crop production. J. Appl. Ecol. 1347 1356. Phillips, B. W., and M. M. Gardiner . 2015 . Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pum pkin ( Cucurbita pepo ) agroecosystems. PeerJ. 3: e1342. Platt, J. O., J. S. Caldwell, and L. T. Kok . 1999 . Effect of buckwheat as a flowering border on populations of cucumber beetles and their natural enemies in cucumber and squash. Crop Prot. 18: 305 31 3. Polk, D. N., K. A. Rosentrater, H. M. Hanna, B. L. Steward, D. Polk, K. A. Rosentrater, H. M. Hanna, and B. L. Steward . 2015 . Factors Affecting Cucurbit Production. Price, P. W., C. E. Bouton, P. Gross, B. a McPheron, J. N. Thompson, and a E. Weis . 1980 . Interactions Among Three Trophic Levels: Influence of Plants on Interactions Between Insect Herbivores and Natural Enemies. Annu. Rev. Ecol. Syst. 11: 41 65. 90 Ranere, A. J., D. R. Piperno, I. Holst, R. Dickau, and J. Iriarte . 2009 . The cultural and chrono logical context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexico. Proc. Natl. Acad. Sci. U. S. A. 106: 5014 8. Rebek, E. J., C. S. Sadof, and L. M. Hanks . 2005 . Manipulating the abundance of natural enemies in orn amental landscapes with floral resource plants. Biol. Control. 33: 203 216. Riechert, S. E., and L. Bishop . 1990 . Prey control by an assemblage of generalist predators: spiders in garden test systems. Ecology. 71: 1441 1450. Riedinger, V., M. Renner, and A . Holzschuh . 2014 . Early mass - flowering crops mitigate pollinator dilution in late - flowering crops. Landsc. Ecol. 29: 425 435. Root, R. B. 1973 . Organization of a Plant - Arthropod Association in Simple and Diverse Hab Brassica Oleracea). Ecol. Monogr. 43: 95 124. Roulston, T. H., and K. Goodell . 2011 . The role of resources and risks in regulating wild bee populations. Annu. Rev. Entomol. 56: 293 312. R ypstra, A. L., P. E. Carter, R.A. Balf our, and S. D. Marshall . 1999 . Architectural features of agricultural habitats and their impact on the spider inhabitants. J. Arachnol. 27: 371 377. Salamanca, J., M. Pareja, C. Rodriguez - Saona, A. L. S. Resende, and B. Souza . 2015 . Behavioral responses of adult lacewings, Chrysoperla externa, to a rose aphid coriander complex. Biol. Control. 80: 103 112. Samnegård, U., A. S. Persson, and H. G. Smith . 2011 . Gardens benefit bees and enhance pollination in intensively managed farmland. Biol. Conserv. 144: 260 2 2606. Sanchez - Bayo, F., and K. Goka . 2014 . Pesticide residues and bees - A risk assessment. PLoS One. 9. Sardiñas, H. S., and C. Kremen . 2014 . Evaluating nesting microhabitat for ground - nesting bees using emergence traps. Basic Appl. Ecol. 15: 161 168. S ay, P., R. Williams, D. Fickle, A. P. Michel, and K. Goodell . 2009 Biology and Behavior of the Squash Bee. Schaefer, H., and S. S. Renner . 2011 . Phylogenetic relationships in the order Cucurbitales and a new classification of the gourd family ( Cucurbitaceae ). Taxon. 60: 122 138. Schipanski, M. E., R. G. Smith, T. L. P. Gareau, R. Jabbour, D. B. Lewis, M. E. Barbercheck, D. a. Mortensen, and J. P. Kaye . 2014 . Multivariate relationships influencing crop yields during the transition to organic management. Agric. Ecosyst. Environ. 189: 119 126. 91 Schmidt , J. M., S. K. Barney, M. a. Williams, R. T. Bessin, T. W. Coolong, and J. D. Harwood . 2014 . Predator - prey trophic relationships in response to organic management practices. Mol. Ecol. 23: 3777 3789. Schultheis, J. R., J. T. Ambrose, S. B. Bambara, and W. a. Mangum . 1994 . Selective bee attractants did not improve cucumber and watermelon yield. HortScience. 29: 155 158. Shackelford, G., P. R. Steward, T. G. Benton, W. E. Kunin, S. G. Potts, J. C. Biesmeijer, and S. M. Sait . 2013 . Comparison of pollinators an d natural enemies: a meta - analysis of landscape and local effects on abundance and richness in crops. Biol. Rev. Camb. Philos. Soc. 88: 1002 21. Shapiro, L. R., I. Seidl - Adams, C. M. De Moraes, a G. Stephenson, and M. C. Mescher . 2014 . Dynamics of short - a nd long - term association between a bacterial plant pathogen and its arthropod vector. Sci. Rep. 4: 4155. Shuler, R. E., A. DiTommaso, J. E. Losey, and C. L. Mohler . 2008 . Postdispersal Weed Seed Predation Is Affected by Experimental Substrate. Weed Sci. 56 : 889 895. Shuler, R. E., T. H. Roulston, and G. E. Farris . 2005 . Farming Practices Influence Wild Pollinator Populations on Squash and Pumpkin. J. Econ. Entomol. 98: 790 795. Simmons, A. M., and S. Abd - Rabou . 2011 . Inundative field releases and evaluation of three predators for Bemisia tabaci (Hemiptera: Aleyrodidae) management in three vegetable crops. Insect Sci. 18: 195 202. Skalski, T., D. Stone, P. Kramarz, and R. Laskowski . 2010 . Ground beetle community responses to heavy metal contamination. Balt. J . Coleopterol. 10: 1 12. Smith, A. A. A., M. Bentley, H. L. Reynolds, and A. A. Smith . 2013 . Wild Bees Visiting Cucumber on Midwestern U . S . Organic Farms Benefit from Near - Farm Semi - Natural Areas Wild Bees Visiting Cucumber on Midwestern U . S . Organic Farms Benefit From Near - Farm Semi - Natural Areas. J. Econ. Entomol. 106: 97 106. Snyder, W. E., and D. H. Wise . 2001 . Contrasting Trophic Cascades Generated by a Community of Generalist Predators. Ecology. 82: 1571 1583. Sotherton, N. W. 1998 . Land use cha nges and the decline of farmland wildlife: An appraisal of the set - aside approach. Biol. Conserv. 83: 259 268. Southwick, E. E., G. M. Loper, and S. E. Sadwick . 1981 . Nectar Production, Composition, Energetics and Pollinator Attractiveness in Spring Flower s of Western New York. Am. J. Bot. 68: 994 1002. 92 Spence, J. R., and J. K. Niemelä . 1994 . Sampling carabid assemblages with pitfall traps: the madness and the method. Can. Entomol. 126: 881 894. Splawski, C. E., E. E. Regnier, S. K. Harrison, K. Goodell, M. A. Bennett, and J. D. Metzger . 2014 . Mulch Effects on Floral Resources and Fruit Production of Squash, and on Pollination and Nesting by Squash Bees. Horttechnology. 24: 535 545. Stallman, H. R., and H. S. James . 2015 ingness to cooperate to control pests. Ecol. Econ. 117: 182 192. Stanghellini, M. S., J. T. Ambrose, and J. R. Schultheis . 1997 . The E ffects of Honey Bee and Bumble B ee Pollination on Fruit Set and Abortion of Cucumber and Watermelon . Am. Bee J. 137: 386 3 91. Steffan - D ewenter, I., and K. Leschke . 2003 . Effects of habitat management on vegetation and above - ground nesting bees and wasps of orchard meadows in Central Europe. Biodivers. Conserv. 12: 1953 1968. Tepedino, V. J. 1981 . The Pollination Efficiency of the Squash Bee ( Peponapis pruinosa ) and the Honey Bee ( Apis mellifera ). J. Kansas Entomol. Soc. 54: 359 377. Thies, C., S. Haenke, C. Scherber, J. Bengtsson, R. Bommarco, L. W. Clement, P. Ceryngier, C. Dennis, M. Emmerson, V. Gagic, V. Hawro, J. Liira, W . W. Weisser, C. Winqvist, and T. Tscharntke . 2011 . The relationship between agricultural intensification and biological control: Experimental tests across Europe. Ecol. Appl. 21: 2187 2196. Trichard, A., B. Ricci, C. Ducourtieux, and S. Petit . 2014 . The s patio - temporal distribution of weed seed predation differs between conservation agriculture and conventional tillage. Agric. Ecosyst. Environ. 188: 40 47. Tscharntke, T., R. Bommarco, Y. Clough, T. O. Crist, D. Kleijn, T. a. Rand, J. M. Tylianakis, S. Van Nouhuys, and S. Vidal . 2008 . Conservation biological control and enemy diversity on a landscape scale. Biol. Control. 45: 238 253. Tsitsilas, A., A. A. Hoffmann, A. R. Weeks, and P. A. Umina . 2011 . Impact of groundcover manipulations within windbreaks on m ite pests and their natural enemies. Aust. J. Entomol. 50: 37 47. Turner, M. G., and V. H. Dale . 2010 Have We Learned? Ecosystems. 1: 493 496. United States Standards for Grades of Cucumbers. 199 7. Unit ed States Department of Agriculture, Agricultural Marketing Service, Fruit and Vegetable Division, Fresh Products Branch, 1 - 7. 93 United States Department of Agriculture, National Agricultural Statistics Service . 2014 . Vegetables 2013 Summary. 1 150. Vidal, M . D. G., D. De Jong, H. C. Wien, and R. a. Morse . 2010 . Pollination and fruit set in pumpkin ( Cucurbita pepo ) by honey bees. Rev. Bras. Botânica. 33: 106 113. Walton, N. J., and R. Isaacs . 2011 . Influence of native flowering plant strips on natural enemies and herbivores in adjacent blueberry fields. Environ. Entomol. 40: 697 705. Wanner, H., H. Gu, and S. Dorn . 2006 . Nutritional value of floral nectar sources for flight in the parasitoid wasp, Cotesia glomerata . Physiol. Entomol. 31: 127 133. Westerman, P. R., J. K. Borza, J. Andjelkovic, M. Liebman, and B. Danielson . 2008 . Density - dependent predation of weed seeds in maize fields. J. Appl. Ecol. 45: 1612 1620. . 2015 . Why birds matter: from economic ornithol ogy to ecosystem services. J. Ornithol. White, S. S., K. A. Renner, F. D. Menalled, and D. A. Landis . 2007 . Feeding Preferences of Weed Seed Predators and Effect on Weed Emergence. Weed Sci. 55: 606 612. Williams, N. M., E. E. Crone, T. H. Roulston, R. L. Minckley, L. Packer, and S. G. Potts . 2010 . Ecological and life - history traits predict bee species responses to environmental disturbances. Biol. Conserv. 143: 2280 2291. Williams, N. M., J. Regetz, and C. Kremen . 2012 . Landscape - scale resources promote co lony growth but not reproductive performance of bumble bees. Ecology. 93: 1049 1058. Winfree, R., B. J. Gross, and C. Kremen . 2011 . Valuing pollination services to agriculture. Ecol. Econ. 71: 80 88. Winfree, R., N. M. Williams, H. Gaines, J. S. Ascher, an d C. Kremen . 2007 . Wild bee pollinators provide the majority of crop visitation across land - use gradients in New Jersey and Pennsylvania, USA. J. Appl. Ecol. 45: 793 802. Woodcock, B. A., J. Savage, J. M. Bullock, M. Nowakowski, R. Orr, J. R. B. Tallowin, and R. F. Pywell . 2014 . Enhancing floral resources for pollinators in productive agricultural grasslands. Biol. Conserv. 171: 44 51. Worthley, H. N. 1924 . The biology of Trichopoda pennipes Fab. (Diptera; Tachinidae): a parasite of the common squash bug. P syche Bost. 31. Wray, J. C., and E. Elle . 2015 . Flowering phenology and nesting resources influence pollinator community composition in a fragmented ecosystem. Landsc. Ecol. 261 272. 94 Zehnder, G., G. M. Gurr, S. Kühne, M. R. Wade, S. D. Wratten, and E. Wyss . 2007 . Arthropod pest management in organic crops. Annu. Rev. Entomol. 52: 57 80. Zheng, Y . H., A. J. Alverson, Q. - F. Wang, and J. D. Palmer . 2013 . Chloroplast phylogeny of 334.