A SURVEY CF THE N355? BQTTQM FAUNA G? A LIMITED AREA OF WINTERGREEN LAKE, KALAMAZQQ COUNTY, MlfiE-EEGAN Thesis For H19 Degree of M. 5. MICHEGAN STATE. UNWERSITY Rudoiph A. Scheibner 1958 A SURVEY OF THE INSECT BOTTOM FAUNA OF A LIMITED AREA OF WINTERGREEN LAKE, KALAMAZCO COUNTY, MICHIGAN by RUDOLPH A. SCHEIBNER AN ABSTRACT Submitted to the College of Science and Arts Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1958 one/(i, 19:37:14:m«u :3 C7 A1::-/1,/r/:3<« ABSTRACT A survey of a limited area of Wintergreen Lake, Kalamazoo County, Michigan was conducted to determine the nature and quantity of the bottom insect fauna, the commun- ities of insects that may exist there and certain aspects of the biology of insects that were present in sufficient quantity to be studied. I From January 1?, 1957 to December 28, 1957, Ekmsn dredge samples were taken monthly from six stations along a longit- udinal transect of the lake. A total of 13,39h specimens were collected in lhh samples for a yearly average of 3,3h8 specimens per square yard. Sixteen families from seven orders were represented. Chsoborus, Leptocerus, Tendipes‘Afl Glyptotendipes and Tanytarsus were the five most important groups collected. The genus Chaoborus and Leptocerus americanus (Banks) were the two most prevalent taxa. The genus Chaoborus was associated with the deeper water and Leptocerus was most common in CeratOphyllum beds in the shallower parts of the lake. Tendipes”flfl a complex of several species of the subgenus Tendipes, was the third most prevalent group and the most generally distributed in the lake. The greatest concen- tration of Tendipes‘fl'was in the shallower areas of the lake. A SURVEY OF THE INSECT BOTTOM FAUNA OF A LIMITED AREA OF‘WINTERGREEN LAKE, KALAMAZOO COUNTY3 MICHIGAN by RUDOLPH A. SCHEIBNER A THESIS Submitted to the College of Science and Arts Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1958 ACKNOWLEDGEMENTS The author wishes to gratefully acknowledge Professor Ray Hutson, Head of the Department of Entomology, who made available facilities of the department and a teaching assistantship during the course of study. For his advice as chairman of the author's advisory committee the author also wishes to express his gratitude. To Drs. Roland Fischer and Peter I. Tack, who critically read the manuscript as members of the advisory committee, the author wishes to state his sincere appreciation. Especial acknowledgement is made to Drs. Gordon Guyer and Walter Morofsky, the author's co-major professors; Dr. Morofsky for making laboratory facilities avilable at the Kellogg Gull Lake Biological Station and his reading of the manuscript, and Dr. Guyer for his constant guidance throughout the study. To Dr. Herman King, the author expresses his sincere gratitude and appreciation for his counsel and advice, and for critically reading the manuscript. To Mr. Van Deusen for making facilities available at the Kellogg Bird Sanctuary and for assisting in selecting a collecting transect of Wintergreen Lake, the author is sincerely grateful. The author also wishes to acknowledge Dr. laVerne Curry of Central Michigan University for determining specimens of Tendipes larvae, and for graciously devoting his time to instruct the author in making determinations of tendipedid larvae. To Messers William A. Drew and Dean L. Haynes, gratitude is expressed for their suggestions and encouragement during the study. II III VI VII TABLE OF CONTENTS INTRODUCTION LITERATURE REVIEW DESCRIPTION OF THE LAKE PROCEDURE PRESENTATION AND DISCUSSION OF RESULTS SUMMARY LITERATURE CITED LIST OF FIGURES I FIGURE I FIGURE II FIGURE III FIGURE IV FIGURE V LIST CF TABLES TABLE I TABLE II TABLE III TABLE IV TABLE V TABLE VI TABLE VII INTRODUCTION The magnitude of pollution, erosion, algal blooms, fertilization, and insecticide contamination in lakes and streams are often measured by their effects on biological conditions. Insect pOpulations, because of their importance in aquatic ecology and their relative ease of being sampled, are a convenient index of general biological conditions. The effects of a large pOpulation of waterfowl on Wintergreen Lake has led some observers to believe that the insect production in the lake may be high. This hypothesis had not been supported by facts from any previous survey. To conduct a complete survey on‘Wintergreen Lake without disturbing the birds in sanctuary there was not possible, so the present study was restricted to a limited area of the lake. The value of a restricted survey was considered, and, in view of valuable data obtained with limited sampling by other investigators of other lakes, it was concluded that the present study could be worthwhile. ‘ ' Therefore, the purpose of this study was to determine with a limited amount of sampling, (1) the nature of the bottom insect fauna of Wintergreen Lake, (2) the habitat of certain insect communities that existed there and (3) the life cycles of those insects that were present in sufficient quantity to be studied. LITERATURE REVIEW Attempts to assess aquatic bottom faunas have resulted in a variety of techniques, but procedures have not been standardized. The following examples are cited to illustrate the variety of techniques and'extent of sampling used by re- putable investigators. There is no intent to make critical comparisons, since each survey was associated with a different problem, and the interpretation of results were also different. Adamstone (1924) formed conclusions about the product- ivity of Lake Nipigon (Area, 1,750 square miles) on the basis of data from 16 series of samples taken over a three year period. Eight to ten hauls with an 81 square inch Ekman dredge on a single date comprised a series. Eggleton (1931), in his study of the profundal bottom of three lakes, used a 36 square inch Ekman dredge to take 1,331 samples from Douglas Lake, Michigan; h03 from Third Sister Lake, Michigan; and 1&5 from Kirkville Green Lake, New York. Not all of the samples from.Doug1as Lake and Third Sister Lake were from the profundal zone. The field work extended over a period of 5% years with intermittent curtailments. In making a survey of a moorland pond, Macan (19A9), at various times, used a special grab-type sampler, a Petersen grab, a pond net and a floating cage to trap emerging adults. The study was for a duration of 5 months. To determine the seasonal food-cycle dynamics in a lh,h80.square meter lake, Lindeman (19h1) took a total of 338 samples in 30 series. The samples were taken at three different zones with a 36 square inch Ekman dredge. Lack of sufficient prior knowledge of sampling conditions, or heterogeneity of sampling sites, sometimes makes the de- sign of sampling procedures difficult. Eggleton (1931) en- countered bottom types that varied from thick ooze to hard sand, and the number of dredge hauls to complete a sample were therefore varied from 5 to 50. Macan (l9h9) designed a grab-type sampler to cOpe with areas that were especially weedy, but he was uncertain of the effectiveness of the sampler in capturing certain insect forms, so a pond net was used to supplement his grab-type samples. However, to corre - late results of samples that are not uniformly collected is not statistically correct, unless the intention is to compare methods. Tent trapping of emerging adults and bottom sampling of immature forms have been used together in attempts to obtain more valid assessments of production in lakes and streams by Macan (l9n9)and Ide (19h0). Scott and Opdyke (l9hl) found little or no correlation between number of emerging insects and the numbers of larvae and pupae sampled from the bottom. Guyer and Hutson (195R) correlated tent trapping results with those 0f kapn dredge samples to determine the efficiency of sampling techniques and obtained significant results with a moderate amount of sampling. Needham and Usinger (1956), in a study to determine the extent of sampling necessary to obtain significant results in a single riffle, found, that to estimate the total wet weight of organisms in the 30 by 100 foot area, 19h square foot Surber samples would be needed to give significant figures with 95 percent confidence, and 73 samples would be sufficient to insure the inclusion of the most common genera. Harris (1957) presented a short statistical method for determining the efficiency of past sampling methods in a stream. The efficiency rating (based on the number of species found in a number of independent sets of samples) may be used to determine the number of samples to take in subsequent series to include a reliable representation of the insect fauna present. This method has application in routine pollutinnal surveys, but the extent of sampling necessary in preliminary surveys is still governed by the intuition of the investigator. Due to the num erous variables in survey methods, such as those mentioned, it is difficult to compare the findings of different investigators, except in very general terms. The following discussion presents representative bottom faunal studies. For convenience the generic names with priority, Tendipes and Chaoborus, are used instead of Chironomus and Corethra when the latter names were used by authors being cited. In his study of the relationship between fish~food and feeding habits of fish in Third Sister Lake, Ball (19u8) presented the quantitative fish-food data in terms of volume and numbers. From April 1939 to May l9hl invertebrates were collected from submerged plants and from the bottom with an Ekman dredge. Sampling was confined to the shallow areas which were the most productive of fish food organisms. The results of the plant samples taken from May to October 1939 are best given in Ball's own words. "The most abundant organism, both by number and by volume, was the caddis. This insect outnumbered even the ever-present midge larvae on the plants of the lake, and comprised nearly twice the volume of the nearest other group.the libelluline dragonflies. The caddis larvae constituted 51 percent of the total volume and #2 percent of the total number of organisms. Next in import— ance in number and volume were the dragonflies, followed by damselflies, snails, midges and leeches in the order named. None of the other invertebrates made up more than 1 percent of the total." For the same period, the volumetric abundance of organisms in bottom samples was dragonfly nymphs, TrichOptera larvae, leeches and midge larvae, named in order of decreasing volume. The first two groups constituted 70 percent of the total production. The descending order of numbers was, caddis larvae, midge larvae, scuds, damselfly naiads and mayfly naiads, all of which constituted about 90 percent of the total nunber organisms collected. In the 1940 bottom sample series,‘ Odonata naiads, TrichOptera larvae and midge larvae constit‘ uted 60 percent of the number and 70 percent of the volume of the macroscOpic invertebrates The scud, Hyalella, was most numerous, but volumetrically represented less than 1 percent of the total. Midge larvae also were much more numerous than the trichonteran larvae, but only had a third as much bulk. The bottom sampling data in l9hl extended only from April 1 to May 16, and during this interval of time a difference in composition of the organisms was evident. Midges alone accounted for 55 percent of the total numbers, and Eyelglla_and mayfly naiads ranked next, constituting 12 percent and 10 percent of the total organisms respectively. The descending order by volume was Odonata naiads, midge larvae, snails and trichOpteran larvae. Hyalella and may- flies, that were numerically important, comprised only 3.62 percent of the total volume. Whereas Ball considered the littoral and sublittoral zones of Third Sister Lake, Michigan,as the most productive of fish-food organisms, Borutsky (1939) considered the profundal zone to be important also in Lake Beloie, U.S.S.R., and limited his paper to the study of the profundal zone. The important organisms of the area studied were Tendipes plumosus (Linnaeus), Chaoborus spp. and Oligochaeta, and of less importance Tanypus spp. Other organisms found in small numbers in the profundal zone, but highly important in the littoral zone were not considered. Johnson (1933), in reporting on the productiveness of nine Minnesota lakes, found that most of the lakes had a predominant Bendiiedic 1i;sleiion. Chaoborus spp., annelids or amphipods were sometimes the most abundant or were a major constituent in some of the lakes. In one lake, Lake Pepin, bivalve mollusks were numerous and ranked second to tendipedids. In each if the lakes, two Ekman dredge samples were taken from each of four types of habitat, the deepest part of the lake, the shallower vegetationless zone, the submerged vegetation zone and the emerging vegetation zone. Classification of lakes according to the kind and abundance of bottom fauna was mentioned by Johnson, but no attempt was made to fit the Minnesota lakes into such a classification. Brundin (19kg) and other EurOpean workers have also used invertebrates in classifying lakes. Pearcy (1953) presented bottom fauna data from Clear Lake, Iowa,that indicated the biomass to be greater in deep water than in shallow water except in October. Hyalella and tendipedids together comprised 85.8 percent of the total volume of organisms in shallow water and 89.1 percent of the total number. In deep water the tendipedids, predominantly Tendipes tentans (Fabricius), constituted 9h.5 percent of the fauna by volume and 55.5 percent by numbers. The free— living flatworm, Planaria, comprised 20.6 percent of the number of organisms in deep water. Macan (19h9) found the shallow vegetated area of Three Dubs Tarn to harbor a greater number of species than the area near the middle of the tarn. The number of specimens collected in the shallows were predominantly Hemiptera, TrichOptera and Hydracarina in that order. About half of the total number of organisms collected in the mid—pond re- gion were tendipedids. Mussels of the genus Pisiduim ranked second in numbers and in the spring ephemerOpterans of the genus Caenis ranked third. In the summer only one specimen of Caenis was recorded in comparison to 386 during the spring. Scott, Hile and Spieth (1938), in their investigation of Tippecanoe Lake, Indiana, considered the littoral zone and the three basins in the lake as separate entities. In the littoral zone(.5-l.25 meters) the important groups in order of descending numbers were Amphipoda, Tendipedidae, snails of the genus ghyga, Hydracarina, Oligochaeta and Ephemeridae. Specimens of the family Tendipedidae alone increased in numbers with increase in depth. 'In the depths beyond 3 meters, the important taxonomic groups were Tendipes spp. Chaoborus spp and Oligochaeta. In two of the basins Chaoborus increased in numbers to the maximum depths of 11 and 17 meters. In the deepest basin the number of Chaoborus specimens increased up to the 17 meter depth, and then gradually decreased to 0 at 37 meters at the basin's maximum depth. The Tendipes distribution varied in each basin. In the deepest basin the pOpulation density was 700-1100 per square meter at depths between 11 and 31 meters. The pOpulation density decreased to 100-200 per square meter at the 3 meter limit of the basin and to 0 per square meter at the 37 meter depth limit of the basin. In the basin with a maximum depth of 17 meters, Tendipes increased from #00 per square meter at the 3 meter depth to 750-850 per square meter in the 13- 17 meter depth range. The shallowest basin showed a steady decrease from 990 per square meter at 11 meter depth to about 25 per square meter at the 3 meter depth. Many papers have been written on the effect of artificial fertilization on fish-food organisms in impounded waters or small lakes. In a preliminary study of fertilization effects on the bottom fauna in Michigan experimental ponds, Tack and Morofsky (19h6) found a tendency toward a general increase in quantity of invertebrates following fertilization. There was a substantial increase in Tendipedidae in treated ponds compared to control ponds. Odonata nymphs and Culicidae larvae also may have been increased in some of the ponds due to fertilization. Ball and Tanner (l951)made observations of the fertil- ization effects produced in a lake of low productivity, North Twin Lake, Michigan. Lack of pre-fertilization data of the bottom fauna precluded comparisons of the fauna before and after fertilation. During the time of fertilization the order of importance volumetrically was dragonflies, caddis- flies, mayflies and midges. The order of prevalence was midges, mayflies, mollusks, caddisflies, dragonflies and scuds. . 0f the many kinds of organism taken during surveys, tendipedids have received much attention, and for this reason are reviewed separately. Tendipedids' frequency, (diversity of habitat, importance in aquatic ecolOgy or value as biological indicators of "pollution" has been noted in many papers. Gaufin and Tarzwell (1952),(l956), and Richardson (1925) reported certain species of tendipedids among the last surviving forms in "polluted" water. Gaufin and Tarzwell (1956) attributed the remarkable ability of Tendipes riparius (Meigen) to thrive in septic and recovery zones of polluted streams to the midge's possession of hemoglobin, which apparently acts in the transportation and storage of oxygen. Walshe (1949) experimentally demonstrated that T. plumosus, T. riparius and related species exhibited complete anaerobiosis for sustained periods of time, and recovered from ill effects in an hour when returnedto aerobic con- ditions. Gaufin and Tarzwell (1956) found species of Tendipes, supposedly pollution tolerant, in clean water, and for this reason cautioned against using tendipedids alone as pollution indicators. The preponderance of tolerant species of tendipedids in septic zones was perhaps due to the quantity of available food, and not due to a septic condition demand. Tack and Morofsky (l9h6) found a tendency toward increased numbers of tendipedids in fertilized ponds that were able to support fish life. Though tendipedids are distributed widely in a variety of habitats, and.can be found in water that is lethal to many other aquatic insects, they are generally associated with and most abundant in shallow water of lakes, ponds and streams favored by abundant growth of aquatic plants (Usinger, 1956; Miller, lghl). Tendipedids are found at various depths. Adamstone and Harkness (1925) found tendipedids in Lake Nipigon at depths of 147 feet, although the greatest pOpulations were at 30 feet or less. Eggleton (1931), Johnson and Munger (1930) and Scott and Opdyke (19hl) found tendipedids common in deep water. Johnson and Munger (1930), in their study of Lake Pepin, found tendipedids, Tendipes plumosus (Linnaeus) in this case, to be scarce or absent in shallow water and in the clean bottom of the river. They recorded concentrations elsewhere in the lake as high as 7,000 per square yard with a probable average of 3,000 per square yard during the month of July. Scott and Opdyke found tendipedids common in deep water, but more of these insects emerged from over shallow water, suggesting that tendipedids, like Chaoborus larvae. may migrate horizontally when emerging. Sprules (19h7),stated that factors, such as bottom type, temperature, currents, and other chemical and physical factors, may have more influence than depth in determining the dis- tribution of tendipedids. Curry (1956), in his study of_T. staegeri (Lundbeck), found this species in water from 1 inch to 57 feet deep, indicating that depth requirements for this species was not critical. Temperature and dissolved oxygen are not as critical with tendipedids as with many other insects, but these do exhibit some distributional and biological effects. Time of emergence and generations per year have been markedly affected by temperature. In controlled experiments on Tendipes tentans, (Fabricius) Sadler (1935) found that hatching time varied.from 17.5 days at 8.8 degrees Centigrade to 3 days at 22.1 degrees Centigrade. When temperature was not a factor, the duration of the fourth and final instar was unaccountably variable, being from h-5 days to 2—3 weeks resulting in an overlap of generations. In nature this may be observed as a relatively constant papulation of larvae with emergences of adults throughout the warmer months. The observed number of generations per year was four plus. Judd (1953) found that emergences as a whole in Dundas Marsh were at their peaks on the day following a peak in temperature. Since 80 percent of the total trapped insects that emerged were tendipedids,these overall results un- doubtedly reflect tendipedid behaviour. Judd recorded the emergence period for T, tentans as May 13 to October 15 with a peak on June 2 much in excess of other times. The high emergence of-T. tentans on one day could be interpreted as indicative of a single generation,*but in view of Sadler's (1935) results this could be the result of overlapping generations coupled with the influence of warm weather. HISTORY AND DESCRIPTION OF LAKE Wintergreen Lake (figure 1), of the Kellogg Bird Sanctuary is located at TlS, R9W; section 8 of Kalamazoo County; and is one of the many lakes of this area classed as a hard water drainage lake. It covers approximately 39 acres and is oval shaped with the greater axis being 1750 feet long and in a northeast to southwest direction. Near the western corner the lake connects with a long oval inter' mittent pond designated as Middle Pond which covers 2.7 acres. Middle Pond's long axis runs in a north by northeast to south by southwest direction, and its southern end connects with Lower Pond which covers 2.h acres and is crescent shaped. A line through the cusps of Lower Pond would run in a north- east to southwest direction. The westerly end of Lower Pond connects with Gull Lake by way of a short stream. At its north corner, Wintergreen Lake drains Upper Pond which is also oval-shaped, with its long axis running northeast by north and southwest by south, and is 0.5 acres in area. A water weed filled lagoon is at the southern corner of the lake. As are most of the lakes of Kalamazoo County, Winter- green Lake is of glacial origin; its basin probably having been formed by the depression of the earth under the pressure of a huge chunk of ice left by the retreat of the Wisconsin glacier. Such pit lakes are typified by their circumjacent hills and their relatively short life. Aging of.Wintergreen Lake is evidenced by the extent of encroaching shoreline. .‘r till.) 1| I'll" .IIII I 1 i....‘l-c - ..J ll. . ,.4 i u: I A. 1, .Cnl‘ I: .‘n .‘\/.t as a . . l . v. ., . ., rHLOH .- ,_fl 4. . n.fi\:.-i.—L Pawn firs r... ...AL.;r 3%. JP... f. “M. .....r. ,. 4 with- P C: . COONUV I. E‘ 1:01 .. r .4 (v r.\. The predominant encroaching vegetation consists of water willow, Decodon verticillatus (L) E11. and buttonbush, Cephalanthus occidentalis L. Nearly all of the littoral zone of the western half of the lake is occupied by yellow water lily, Nuphar advena Ait, whereas the eastern half of the lake has a sandy shoreline except for a Aooofoot Nuphar advena bed at the eastern corner. The submersed plant,coontail, Ceratophyllum demersum L. is confined to a band around the lake between the depths of 4 and 18 feet. Around the 12 foot depth at the southwest end of the lake, there is a scattered amount of the pondweeds PotamOgeton pgctinatus L., Potamogeton foliosus Raf. and Najas flexilis (Wild) Rostk. et Schmidt. Beyond the 18 foot depth there appears to be no rooted vegetation. Temperature stratification data taken by Gull Lake Biological Station students in 1956 and 1957 showed that no hypolimnion existed in the lake during the summer stagnation, but a thermocline was present at the deepest part of the lake. According to a conversation with Mr.‘VanDeusen, who has occasion to discuss the lake with natives of the area, Wintergreen Lake, prior to 1926, had long been known as an excellent fishing hole. Fetterolf (1952) in his fish p0pue lation study of the lake reported that the poundage per acre of game and pan fish was higher than in any other lake for Which he had records. In 1926, w. x. Kellogg had acquired all the property surrounding the lake, and inaugurated Operations to main- tain the area as a bird sanctuary. Later, in 1929, the property was deeded to Michigan State University to continue the sanctuary's Operation. Besides providing a haven for birds, the main objective at the sanctuary has been to study the various aspects of migratory waterfowl. To obtain more complete information to this end, other investigations not in themselves ornithological, have been encouraged. It is ,for this reason, in part, that this study of the lake was encouraged. PROCEDURE A preliminary examination of Wintergreen Lake was made to select sampling sites which would give a satisfactory index of the bottom insects and yet not interfere with the birds in sanctuary. With primary concern for the birds, a random grid selection of sites or numerous cross transects had to be discounted. A median longitudinal transect seemed most satisfactory under these conditions, since it was usually unobtrusive to the birds, it crossed the lake's greatest depth and terminated on shores with littoral zones that were representative of the rest of the lake. The stations along the transect also were not selected at random, but were selected on the basis of depth, bottom type and rooted vege- tation. Station 1 was at the southwest end of the transect in 3 feet of water proximal to the greatest concentration of Nuphar. The bottom was sand and silt but covered by detritus to the extent that dredge samples seldom contained anything but detritus. Station 2 was in 10 feet of water, and had a bottom that was composed primarily of silt and detritus, the prOportion varying with the seasons. A sparse growth of Potamogeton was present but it was rarely taken in any of the samples. The conditions at station 3 were similar to those at station 2 except that there was less rooted vege- tation, the prOportion of silt to detritus was higher and the depth was 15 feet. Station 4 was at the lake's greatest depth of 21 feet, and was the most constant station as far as consistency of the bottom was concerned. The depth of the ooze was not determined. It was dark black in color and had a consistency that was almost gelatinous. Station 5 was located at 18 feet where the bottom contour declined sharply. This was normally the outer border of the CeratOphyllum bed at this part of the lake, but wind and wave action sometimes caused this vegetation to be scarce or lacking at this spot. Station 5 was by far the most variable in bottom type. It varied from primarily detritus to marl to ooze with a varying amount of rooted vegetation. Station 6 was at the northeast end of the transect in 6 feet of water and CeratoPhyllum was always present. The bottom was a composite of marl and detritus. No definite time limit was set for sampling, but it was agreed with Mr. Van Duesen, who manages the sanctuary, that an attempt would be made to be on the lake for only a short time. Preliminary sampling in October and November of 1956 indicated that even with the assistance of a second man, three or more hours might be required during inclement weather to take two samples at each of seven stations. This amount of time was in excess or what was h0ped would be the max— immm, but by reducing the stations to six and relying on good weather for sampling, it was thought that this time could be reduced. In view of the variation in intensity of sampling used in the past by other writers, it seemed feasible to Obtain valid information even with the restrictions im- posed. The sampling was begun in January 1957 when the lake was frozen and could be walked on. At each of the stations 3 hole was cut through the ice about 3 feet long and wide enough to accomodate the 6x6'Ekman dredge and a foot square screen which was placed under the dredge before lifting it from the water. The use of the screen was to recapture any insects that might escape in the overflow from the dredge. A sample was taken from each end of a hole in an attempt to avoid sampling an identical spot. Each sample was emptied into a separate galvanized pail that was labelled with the station number and the letter"A" or "B" designating it as the first or second sample from that station. The samples were then taken ashore where they were preliminarily washed with a 20 mesh screen to remove enough silt so the sample could be stored in a gallon jar. This screen was the same one used during the sampling process. Clear water was added to cover the remaining mud. The reduction of the sample volumes facilitated their transportation to East Lansing when time was insufficient to sort the samples immediately. Usually much of the sorting could be done at the Gull Lake Biological Station laboratories near by. The sampling method was the same when the ice was out except that the sampling was done from a boat. Buoys were used to mark the stations at first, but prevalent high winds caused them to break loose or drift, so beginning with the May collections their use was discontinued altogether, and the landmarks originally used to lay out the stations were relied upon for orientation. At East Lansing, unsorted samples were kept alive in a constant temperature room held at 15 degrees Centigrade. It was felt that live insects could be more easily detected and sorted, although there was some danger in holding the samples too long because of emergences and predation. Sorting was a tedious task averaging four hours per sample. Even after thorough rinsing some samples still had a volume of two quarts which was then examined a tablespoonful at a time. These small subsamples were diluted in a half pint of clear water in a white pan and picked over by hand. Specimens of Chaoborus were difficult to detect even under this condition so the subsamples were poured through a screen after having picked out the other insects. 0n the screen the Chaoborus were easily seen and handled. After the first four subsamples when no ChaOborus were found and it seemed likely that none would be found, the use of the screen was discontinued for sorting the remainder of that sample. The insects collected in January and February were kept in Dietrich's fixative for 2h hours before transferring them to permanent storage solution (70% alcohxn, 26% water and h% glycerine). However no particular advantage seemed to be gained with this treatment so all subsequent collections were put directly into vials of permanent storage solution with their collection data labels until they could be identified and tabulated. 21 PRESENTATION AND DISCUSSION OF RESULTS The number of samples is admittedly small, a fact of which the writer was aware at the outset, however this was necessitated by the limit of time desired to be spent on the lake during the birds' nesting and migratory periods. ‘With the number of samples reduced, the probability of getting reliable results was also reduced. Relying on chance that the variation between the'Afand'B‘samples would be small, the data were tabulated meticulously as for a more extensive quantitative study.- Great variations between the'N'and'B"samp1es often did exist, but despite this fact the data on the whole do in- dicate that a substantial bottom insect pOpulation did exist in Wintergreen Lake. The total of lhh samples taken through- out the year with a 36-square inch Ekman dredge yielded a total of 13,39h specimens, or an average of 3,3h8 per square yard for the year. Sixteen families from seven orders were represented. Dipterous and TrichOptera larvae and pupae constituted 68.8 percent and 26.h percent of the total collected numbers respectively. Only five taxa, Chaoborus, Leptocerus, Tendipes "A", Egyptotendipes and Tanytarsus appeared in sufficient numbers to indicate definite facts about their biology. Tendipes "A" is a complex of several species which is elaborated on later in this paper. The data recorded in tables 1-7 show the seasonal variation of the various taxonomic groups. In table 1 the data from a series composed of 12 samples per collection a; 2 no. Ho.m Ho. no. HO. NH. mH. 3.3 :0. mm. sH. Ho. em. mo. mo. OH. mm. om.: mo.s oz. mo.H Hm.s :H.H a mew O\r-l mH somm HCU r‘l Nc>flfiCfiqub—CVH3\r4l3\:rir\ HOV“ :an H :rOCur—i mm (13 L0 \0 mmH :n.mm mpmw Hapoa no a .008 O") OH N O Na C\O\H H (U (U (U H H mm com CO .:r U’\\O\L') UK N m (13$ UN me 0H >hu7H .muaH zmmmommezH: some ma02 poo Hmow mmoH squ smmH HsmH wmmH ”Hmpoa HuHscMH ponon mHoHupn mon omOHon oacHxHuoo .mgm muooaouoz eachoesouoz «mmamHzmm oacHHapmm «mmamoaHmmn H Sam «Hanson oanHHoBommsno z .oflm 3:0ch mmmHommmhn AHHEEV saw nscpopnodoru omcHHHnQOpcmm uon . NH m H gm: new as H m H m 2 no no .H ms. HH H H m m .amm.MHHBOMHam m m .mmm usponouno (mmHmHn mm H H H CU H H O\ O H [g \0 O: H m NH mm m.sm HwH m mm NH HH H (U .-.r mm m Hm mm O\ H 0004mm H m «:t'CUr-i mmmm grinm Hm :r O (\I minim (UH oo Hmuoa mm 0H m :H HH m H mm m mH m «H mo R .909 can >oz poo mom mn< Huh a: pa< pa< has pom nah zachon .muaH zmmmemmazH: zH .H ona02 poo new ms< Haw has un< ua< no: new can z<0Hm0HZ .mM¢H zmmmwmmBZHk 2H .m ZOHBoz poo now ms< .Hapop on» No HH Hm o: om H H m w m m H m H m m N m a H mH mm om m H m m Huh was ma< pa< H: QMH mm m (\l m (U (“\DO") m Hm mm Hm mH m «H has pom can .Qmm pcoo you H can» 2th Hapos 5.5m mannoumHmorH. “mummbmuuo .Qmm «a m an dam «.3533 .lllKPKano .mmm nsmoHoaK .mmm anoao «mmanpmmfimmmm .Qam unnooopaoq InmmanpmpHma .mmm nsH «m00pm .mmm .mmm. Gian-H .mgm nonpmpmaw noflwonomomm‘Hv non so um” 45:: £3 .mmm «H 0 Hum dam 3.89028 oz poo now ms< Huh «2 ua< pa¢ was Duh nah zHonOHz .muqH zmmmommazH: 2H “H onHHHm a< mamoc .B H :m: IIIWE 80 . m m .<: av 90 H . m mHNEomHam mHH uH m HH mm 0H: oHH H pm .mmm asponomno 02 poo mom ms< Huh a: pa< na¢ pm: pom nah $4 0 R 5onon .83: zmmmummaz; E .m 28.3.5 .2 2.3 205838 mum 322% monmmn 558 men Egg me wamHme 029 zH mmsomgqoo maommzH no mmmmzpz H02 900 new (\lHr-i afi'H ms< Huh Hmpop on» no unoo you H can» mung: HHm HOH mHH OH :H Hm m mm :5 (\J m m (\1 mm 00: 81M \0 mam 3m 5w m: mm: om HHH HHH m H 0H .32 Hm mam OONH Hapoa oaoHHaphm nmEmDDHmmH .3me mHoHubm mOHm .nfim manoooHoauom KmEme—mm .m% 233on .mmm «H528 «.505 .%5 nHavanuom .mmm anmmuomHng .mmm «HSHHomHH H .QnHm NE a_ _ «Gm .m% «5533.. ”322000 .93 3.33. mmmsmbmmzflmmm .93 a: 95:00 How .mmm anooob .HHHHm nooonoaHmB .mHH dam usuooopaoq ImmmHLDMmea .mmm nHHHbaHOOHm .QHHm asaonofinoonsonh .mmm assocoHHnbopamuo 53m a: 0% 0 HM .m% 3.6:» can. mm .93 uoaHmcom -omath Ahmwmwpmv MSQOHCOHH .9 m ._m.. E OH :4: noavawa H .93 «HhaoaHMm m .QO 3.80.030 oz poo mom ms¢ Huh can has HQ< has new .opmo aoHoouHHoo you noHoEmn omoopm swexm mH non Anxnmmv mneoHnoam nspoooumoq no saunasz Haves d1 th. 00H i com com 00H 4 com com com l com com . OOOH OOHH .m mmbon °satdmes afipalq uemxg at 13d snlaooqdaq JO elaqmnu Iaqom 36 numbers on April 26 and August 11 is interpreted as periods of emergence. That emergences were occurring during August is corroborated by notes taken while sorting that state that many pupae of Leptocerus appeared in the August collec- tions. Pupae could be recognized through their translucent cases by their long antennae which were coiled several times around the posterior end of the body. Pupae were not noticed in the April 26 collections, although they may have occurred. To save time, space and material the specimens of Leptocerus were not saved, so it was not possible to recheck for pupal occurence in the April collections. ' High winds (30-35 mph according to radio weather report for March 16, 1957) sometimes hampered collecting and changed the nature of some of the stations in regards to the amount of vegetation, and hence, the number of Leptocerus larvae that may have been collected. The weather on April 26 was moderately windy with slight rain in the Wintergreen Lake area, which made collecting difficult, but vegetation was not appreciably disturbed at the stations. ‘Wind disturbances were not noticed at any time at station 6. If disturbances had occurred, it would have meant an increase in vegetation and Leptocerus specimens since the prevailing winds blew across the lake in the direction of this station. Yet the data pre- sented in table 7 show that the numbers at station 6, where Leptocerus was most common, followed the general trend in the lake and decreased in number in the April 26 collections. The decrease was interpreted as due primarily to an emergence. Considering the time of the year, the low values recorded for February were regarded as aberrant. The group, designated Tendipes "A", is a composite of several species of the subgenus Tendipg§_that have tripartite median labial teeth, 2 pairs of ventral abdominal gills, lateral lobes on the tenth body segment and in most cases u black mandiblar teeth, although occasionally with 3 black and 1 yellow mandibular tooth. According to Curry (1955) this would include the species plumosus (Linnaeus), tentans (Fabricns), £2513 (Curran) and staegeri (Lundbeck) and according to other writers T. decorus (Johannsen) as well. Slide preparations of a representative selection of various sizes of Tendipes "A" from all stations for various dates were examined and were determined as 90 percent T. plumosus. The mounts were taken to Central Michigan University at Mt. Pleasant where Dr. LaVerne Curry kindly verified the determinations and corrected some of the determinations that had been misdetermined as T. staegeri by the writer. These specimens had atypical characteristics of the epipharyngeal teeth that were similar to those of T. staegeri. Dr. Curry pointed out some characteristics that were helpful, and, mentioned that the number of black mandibular teeth had not been a reliable taxonomic character among specimens of T. plumosus in his collection, although four black mandibular teeth seemed a reliable character as used by other taxonomists. The complex, Tendipes "A", was the most versatile of the taxa in that it appeared at all the stations at least 38 during some part of the year. From the data presented in tables 2 through 7, a preference for the vegetated and shallow areas was exhibited. If it were assumed that the complex was predominantly T. plumosus, this would contradict the findings of Adamstone (1925), Johnson and Munger (1930), Scott, Hile and Spieth (1938) and others who found this species confined or most abundant at depths greater than 18 feet. The tables show the yearly total of Tendipes "A" at station A to exceed only one other station, station 2, at a depth of 10 feet. Station 6, which was 6 feet deep, contributed 58.&% of the total numbers collected. The paucity or absence of insects during the summer was interpreted as primarily due to emergence of adults, although predation undoubtedly accounted for some of the decrease from previous months. The erratic appearance of the figures from January 12 to July 18 may have been influenced by the extent of sampling. Guyer (1952) reported that he found Tendipes in colonies, thus variations in numbers could be recorded from samples taken close to each other. If this is so, it is likely that, with the limited samples taken here, fluctuations in numbers might be recorded that have no significance in indicating emergence of adults. Because the study was being conducted from headquarters 70 miles from the lake, it was not feasible to use tent trap methods to establish emergence periods. As an alternative, the larvae were measured and recorded to ascertain if growth rates would indicate emergences other than the general 39 emergence for the summer. The results are given in figure U. Since pupae are shorter than their respective mature larvae, they were considered as 28/mm long in the calculations to give a better indication of maturity. In figure a the mean lengths of the collections are connected by a longitudinal line which indicates the change in mean lengths. The vertical lines terminated by X's give the upper and lower limits of two (standard deviations) from the mean. The inconsistency of the dispersion indicated in figure A was perhaps due to differences between the species within the species complex besides irregular growth patterns within the predominant species, 2; plumosus. No other emergences were indicated by this method. Curry (195h) had noted that I, tentans larvae may pupate when they were 9—21 mm. long. That such variations may have occurred, in a complex like Tendipes“§'is very likely, but the total effect was not considered important in interpreting the results here. ' The sampling results of Glyptotendipes and Tanytarsus (Figure 5) showed similar trends, thus the two genera were considered together. The parallelism of the time and location of the appearance of these two genera was interpreted as their being identical in habit. Only in March and May at station 2, were Tanytarsus specimens taken in significant numbers without a corresponding appearance of Glyptotendipes specimens. The large numbers of Tanytarsus and Glyptotendipes larvae fir 1 4X )( . «in *‘w. - - I L \A. Ar x it .44 hl OUQ 4 >02 open coHuooHHoo poo mom ms< Hsh ash he: n OOH . omH . oom monpmuhcma nooHocopopoHHu . 0mm . oom . 0mm .opmo coHpoaHHoo nod nuHaEmn umooun nmsxm NH 90 noHpon poo .Qon unnumUHCmB Dom .Qan nouHocouothHo ho muonssn Haves .m mmDOHm -sa[dmas aSpaiq uemxa 30 801198 lad suamroads JO laqmnu Iaqom h. (‘) that were collected in October, and persisted above the yearly average into November, is interpreted as the progeny of a hatch that probably occurred in midsummer. Lack of data, other than what appears in tables 2-7 and figures 5 and 6, precludes drawing further and more definite conclusions since the two genera may have been composed of several species. An attempt was made to compare the insect populations of Wintergreen Lake with other lentic waters. Much of the published data available were not obtained from general surveys, were procured by a different method or were pre- sented in a form that could not be compared. Therefore the following comparisons are not exact, and some of the infers ences may be biased. The figures given by Scott and Opdyke (19hl) average 2,177 dipterous larvae per square meter in Winona Lake in June and August of 193A and 1938. When the data in table 1 is extrapolated for comparison, it shows an average of 2,732 dipterans per square meter for the year. The June collection was not taken in Wintergreen Lake, but the August collections yielded only 55 dipterous larvae of the total 76 insects collected. The extrapolated equivalent of the August data is 792 dipterans per square meter, a figure much lower than what was recorded for Winona Lake for the same period. No other information is given about other bottom insects or conditions at other times of the year in Winona Lake. The data given by Macan (l9h9) was difficult to compare, since a variety of sampling equipment was used. However a ”3 comparison of weed faunas in Three Dubs Tarn and in Winter- green Lake showed differences in faunal composition. Caddis, corixids and ephemerOpterans were the predominant insects in the shallow weedy area of Three Dubs Tarn, whereas the pre- dominant insects in the shallow weedy area of Wintergreen lake were tendipedids and caddis. Virtually no corixids and few ephemerOpterans were taken from Wintergreen Lake. Tendipedids were predominant in the deeper parts of Three Dubs Tarn, and tendipedids, though an important group in Wintergreen Lake, were rarely collected in the deepest part of the lake. In general.the pOpulations of tendipedids and corixids in Three Dubs Tarn were greater than in Wintergreen Lake, but all other insects common to both lakes were more numerous in Wintergreen Lake. The unusual pOpulation of Tendipes plumosus in Lake Pepin reported by Johnson and Munger (1930) was much larger than the average for a comparable group, Tendipes "A", reported here. Tendipes "A", which was estimated as 90 per— cent 2. plumesus, averaged 165 per square yard for the year and #56 per square yard at their maximum in March. The July average in Lake Pepin was 3,000 per square yard. The largest single sample of Tendipes "A" in Wintergreen Lake compares favorably only with the July average of T. plumosus in Lake Pepin. Borutsky (1939), in reporting on the biomass of the profundal of Lake Beloie, U.S.S.R., gives density figures for Chaoborus which average larger than the figures that are nu given here. Most of the Lake Beloie data were from depths greater than occurred in Wintergreen Lake, and Chaoborus pOpulations tended to increase with depth up to a limit in deep lakes. The pOpulation densities increased to a max- imum at 11 meters and then declined beyond this depth. The pOpulation densities of Chaoborus in Wintergreen Lake were from h-9 times greater than pOpulation densities at similar depths in Lake Beloie. Scott, Hile and Spieth (1938) when observing the trend of Chaoborus in three separate basins in Tippecanoe Lake noted that pOpulation densities increased up to the maximum depths, 11 and 17 meters, in the two shallower basins. In the basin that was 37 meters deep, the pOpulation densities reached their maximum at 17 meters, and then decreased ' gradually to O at 37 meters. At corresponding depths in each basin (the range from 3-11 meters) the pOpulation densities were greater the shallower the basin. The maximum density, 990 per Square meter, was recorded at the maximum depth in the 11 meter basin. The yearly average for ' Chaoborus at the deepest part of Wintergreen Lake was 9893 specimens per square meter, during the period of maximum recorded abundance in February the pOpulation at station A ‘was 3A,387 per square meter. Brydon (1956) when reporting on the control of the (3lear Lake gnat, Chaoborus astictgpus D. and 8., found the Ilarvae most abundant in Clear Lake, California in March. The érverage concentration in the lake bottom during this time was 39.96 per square foot. Emergences of adult Chaoborus from Clear Lake, augmented perhaps by emergences from lesser bodies of water near by, during June and late September, were con- sidered an extra nuisance in the area. Although the con- centrations of Chaoborus larvae in Clear Lake are much lower than those recorded for Lake Beloie, Tippecanoe Lake and Wintergreen Lake, the pOpulation in Clear Lake is evenly distributed throughout the lake and the average productivity per unit area of the entire lske may be greater than any of the other lakes mentioned. / 'rx SUMMARY Ekman dredge samples were taken from the bottom of Wintergreen Lake from January 1957 through December 1957 from six stations-located on a longitudinal transect. A total of 13,39h specimens were collected, or an average of 3,3h8 per square yard for the year. Sixteen families from seven orders were represented. Five taxa that appeared most often were Chaoborus, Lgptocerus, Tendipes "A", Glypto- tendipes and Tanytarsus. Chaoborus was the predominant genus collected during the study, and was composed of two species, 9, flavicans (Meigen) and 9. punctipennis (Say). The genus Chaoborus was associated with the deeper part of the lake, but mi- gration to shallower water during emergence was noted. Three major emergence periods were determined, one in latter March, one between April and July and one in November. Leptocerus was represented by a single species, Leptocerus americana (Banks), and constituted 26.h per cent of the total number of insects collected and 98.8 per cent of the TrichoPtera specimens. Leptocerus larvae were asso- ciated with Ceratophyllum in the shallower areas of the lake. Two major emergence periods were determined, one in latter April and another in August. The larvae of the Tendipes "A" group were the most widely distributed appearing at all stations during some period of the year. They were most prevalent in the shallower water of the lake. Tendipes "A" was composed of approximately A? 90 per cent 3. plumosus larvae. The group was too complex to determine whether important emergences occurred other than during the summer months. The genera Qlyptotendipes and Ignytarggg were similar to each other in distribution and frequency. Both génera . were associated with vegetation in the shallow parts of the lake. The preponderance of Tanytarsus and Glyptotendipes specimens in the October collections was interpreted as the progeny of adults that emerged during the summer. No other emergences were clearly indicated. M8 LITERATURE CITED Adamstone, F. B. y 1924 The distribution and economic importance of the bottom fauna of Lake Nipigon. Univ. of Toronto Studies, Biol. Ser. 25: 35-100. Adamstone, r. B. and J. K. Harkness 1923 The bottom organisms of Lake Nipigon. Univ. of Toronto Studies, Biol.Ser. 22: 123-188. Ball, Robert C. l9h8 Relationship between available fish food, feeding habits of fish and total fish production in a Michigan lake. Mich. St. Coll., Agr. Exp. Sta., Tech. Bul. 206. 59pp. Ball, R. C. and H. A. Tanner 195] Tee effects of fertilizer on a warm water lake. Mich. St. Coll., Agr. Exp. Sta., Tech. Bul. 223. 32pp. Borutsky, E. V. 1939 Dynamics of the total benthic biomass in the pro— fundal of Lake Beloie. In Russian.Proc. Kossino Limnological Sta. Hydrometeorlogical Serv. of U.S.S.R. 22: 196-218. Translated by Michael Ovchynnyk. Brundin Lars 1959 Chironomiden und andere bodentiere der Sudschedischen urgebirgsseen. Inst. of Freshwater Res., Rep. No. 30: Ssh-91A. Brydon, H. W. 1956 The Clear Lake gnat and its control in Clear Lake, California during l95h. Jour of Econ. Ent. A9: 206-209. Curry, LaVerne L. ~ l95h An ecological study of the family Tendipedidae of two fresh-water lakes in Isabella County, Michigan. Unpublished Ph.D. thesis, Mich. St. Coll. 1955 Prelimmary larval key for the genera of Tendipedinae (-Chironominae) with special reference to the genus Tendipes. Mimeo. 8 pp. Not approved for pub. 1956 Notes on the ecolo y and taxonomy of the midge Tendi es (Tendipes? staegeri (Lundbeck)—thronomus staegeri Lundbeck_(Diptera)3 Hot. News. 693 225-236. “9 Eggleton, F. E. 1931 A limnological study of the profundal bottom fauna of certain fresh—water lakes. Ecol Monogr. 1:231- 332- Fetterolf, Carlos 1952 A pOpulation study of the fishes of Wintergreen Lake Kalamazoo County, Michigan with notes on movement and effect of netting an conditions. Unpublished M.D. thesis, Mich. St. Coll. Gaufin, A. R. and C. M. Tarzwell 1952 Aquatic invertebrates as indicators of stream Pollution. Pub. Health Rep. 67: 57-6h 1956 Aquatic macro-invertebrate communities as indicators of organic pollution in Lytle Creek. Sewage and Indust. Wastes. 22: 906-92u Guyer, Gordon B. 1952 A quantitative and qualitative investigation of the adult midges of the family Tendipedidae in fertil- ized ponds. Unpublished M.S. thesis, Mich. St. Coll. Guyer, G. E. and R. Hutson 1954 A comparison of adult and immature sampling tech- ni ues utilized in an ec01ogica1 study of pond insects. Jor. Econ. Ent. MB: 662-665. Harris, E. K. 1957 Further results in the statistical analysis of stream sampling. Ecology 38: h63-h68. Ide, F. P. 19h0 Quantitative determination of the insect fauna of Eapid water. Univ. of Toronto Studies, Biol. Ser. 7: 1 20. Johnson, M. 1933 Preliminary report on some Minnesota lakes and their productiveness of fish food. Univ. of Minn., Tech. Bu11., Agr. Exp. Sta., 90. 3] pp. Johnson, M. and F. Munger 1930 Observations on excessive abundance of the midge Chironomus plumosus at Lake Pepin. Ecology 11: 110-126 Judd, W. W. 3953 A study of the pOpulation of insects emerging as adults from the Dundas marsh, Hamilton, Ontario, during 1948. Amer. Midl. Nat. M9: 801-82“ 5O Lindeman, R . L. 1941 Seasonal food cycle in a senescent lake. Amer. Midl. Nat. 26: 636-673. Macan, T. T. ’ 1949 Survey of a moorland fishpond. Jour. Animal Ecol. 18: 160 186. Miller, R. B. . , 1941 A contribution to the ec010gy of the Chironomidae of Costello Lake, Algonquin Park, Ontario. Univ. of Toronto Studies, Biol. Ser. 49: 1 63. Needham, R. R. and R. L. Usinger 1956 Variability in the macrofauna of a single riffle in Prosser Creek, California, as indicated by the Surber sampler. Hildgardia, 24: 383-409. Pearcy, W. C. 1953 Some limnological features of Clear Lake, Iowa. Iowa St. Jour. of Sci. 28: 189- 207. Richardson, R. E. 1925 Changes in the small bottom fauna of Peoria Lake, 1920-1922. Ill. Nat. Hist. Surv. Bul.. 15:‘323-390. Sadler, W. 0. 1935 Biology of the midge Chironomus tentans Fabricius, and methods for its pr0pogation. Mem. ‘COrnell Univ. Agr. Exp. Sta. 173 25 pp. 1938 The bottom fauna of Tippecanoe-Lake. Invest. Ind. Lakes and Streams 1: 5-16. ScOtt, w. and D. F. Opdyke 1941 The emergence of insects from Winona Lake. Invest. Ind. Lakes and Streams 2: 5-14. Sprules, W. M. 1947 An ecological investigation of stream insects in Algonquin Park, Ontario. Univ. Toronto Stud., Biol. 361'- 56: 1'82- Tack, P. I. and W. Morofsky 1946 A preliminary report on farm pond management in Michigan. Mich. St. Coll., Agr. Exp. Sta. Quart. Bul. 28: 294-303. Usinger, Robert L. 1956 Aquatic insects of California. Univ. of Cal. Press 508 pp. illus. 51 Walshe, B. M. 1949 The function of haemoglobin in Chironomus plumosus under natural conditions. Jour.‘Exptl.“Biol. 27: 73-95 u - a on. dogs, 1‘ '9 C7. U; -q .. - .1 w- : .. :. .\:Ii“ '3 -5V la: flu. mm W W DI “I"414174114114!”iillfilil‘l‘fl'es 3 1293 03169 4049