V53“. .. f; 2;: -~ M .A ..., I. A qumnmnva ma numumwa lNVESTfiGATIQN 05 THEADULT mumsas OF THE FAMILY newnwzmms m FERT!LIZED AND mammary pawns 111033: for the Degree of M, S. MICHtGAN STATE COLLEGE Gwdon Earl Guyer 1952 ML!" ‘ Ir 7 IWMWMI ' . 31293019955919?" 4 ., .- . : -‘., 7.;1- ,, A .._..,__L.._o__'._.'_..'__x not vafuado Thihtower‘tfig'lmt‘the , earl: onadwlva '1 "icy -...~.«.~.‘ 1'. I". . I ...-..- — thesis entitled _ : ~ ' : .5 '54.} ., r - 3:..u...s F" ' ‘ m!” : tA_QU§N_1TITMI‘LQAMfQUngIJAflVE . $. ‘ENVESTIGATION w THE ADULT MIDGES * _. - . _ A- ' . .-QF. ,THE .FAMIfLY -IENDIBEDIDAE ‘ _ ‘IN FERTILIZED AND UNFERTILIZED PONDS ‘ presented: Blj .r..—- n" I _; Gordon Earl Guyer 1:; h has been accepted towards fulfillment ' I . of the requirements for ‘ Master degree in Entomology \Q 1 [.1 f ajor professor Date February 29, 1952 PLACER RETURN ”Xhmmfllbmflunyumd. TOAVOIDFINEI madman-due. MSU I. An Afflnnutlve Adlai/Ewe! Oppommty lmlmlon w A QDANTITATIVE AND QUALITATIVE INVESTIGATION OF THE ADULT MIDGES OF THE FAMIEY TENDIPEDIDAE IN FERTILIZED AND UNFERTILIZED PONDS By GORDON EARL GUYER A Thesis submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1952 Illlllll‘lllll 1" Illlllul (Mr/J z 5gJ ACKNOWIEDGMENTS I The author wishes to express his sincere thanks to all members of the Department of Entomology and especially to Professor Ray Hutson, departmental head, and Professor W} F. Morofsky under whose constant supervision and kind guidance this thesis was prepared. He is also greatly indebted to Doctor Peter I. Tack, head of the Department of Fisheries and Wildlife, Michigan State College, for his sincere interest and valuable suggestions. The investigator wishes to thank Mr. Ashley Berridge, Superintendent, Lake City Experiment Station, for his kind cooperation and assistance in the oper- ation of the ponds. Acknowledgment is extended to Doctor Alan Stone and Doc- tor Willis W} Wirth.of the United States National Museum.for the verification of the identifications of the members of the families Tendipedidae and Heleidae. TABLE OF CONTENTS I. INTRODUCTION . . . . . . . . . . . . . . II. LITERATURE REVIEW . . . . . . . . . . . . III. OBJECTIVES . . . . . . . . . . . . . . . . IV. EXPERIMENTAL STUDIES . . . . . . . . . . . A. Description of ponds . . . . . . . B. Description of trap . . . . . . . . C. Sampling of adult insects . . . . . D. Light trap . . . . . . . . . . . . E. Laboratory procedure . . . . . . . V. NOMENCLATURE . . . . . . . . . . . . . . . VI. A LIST OF INSECTS RECOVERED FROM THE FUNNEL TRAP SAMPLES VII. DISCUSSION . . . . . . . . . . . . . . . . A. Relative abundance of various subfamilies Table l (The Subfamilies of Tendipedidae) . . . Figure 1 (Percentage Composition I of Subfamilies . . B. Tribe Calopsectrini . . . . . . . . C. Subfamily Pelopiinae . . . . . . . D. Subfamily Hydrdbaeninae . . . . . . E. Family Heleidae . . . . . . . . . . F. Family Culicidae . . . . . . . . . Page #05me 10 12 13 14 16 18 20 20 21 22 23 25 26 27 27 IlI‘nl u[ll|l||1l [[[II C O O O u e o e . - . I G e v . Q I I .. e D O D . e e u a . o g . e . . u . p I e . ‘ d .. O s A v I A n . I e u I a n O o O O Q A O ' {I'll O O O n A e v Q o c O a I e o o O O t o O c O f e n o o C e . O O o VIII. IX. X. Table of Contents (Con't.) C. Other insects sampled . . . . . . . . . He Tribe Tendipedini e e e e e e e e e e e 1. Seasonal variation . . . . . . . Figure 2 (Seasonal Variation of Temperature and Tendi- pedini Population . . . . 2. Variation of pond populations . Figure 3 tion of Insects by Ponds). 5. Species of the tribe Tendipedini Figure 4 (The species of Tendipedini) . . . . . . . Table 2 (The species of Tendipedini) . . . . . . . Tables 3 through 8 (Seasonal SUMMARY . . . . LITERATURE CITED Distribution of Species of Tendipedini found in Pond A, B, C, D, E, and F) e o m TD PLATES O O O O O O O O O O O O O O O 0 (Percentage Distribu- 29 29 29 30 52 54 56 58 39 40-45 ‘ 55 54 58 I INTRODUCTION The popularity of the farm pond program throughout the United States has increased rapidly in the past several years. There has developed simultaneously a sharp interest in bio- logical production of small ponds with.special emphasis on fertilization to increase production. Members of the family Tendipedidae have been Observed to respond exceedingly well to the application of fertilizer and it is with this thought in mind that this study was under- taken. Since the larvae of members of the Tendipedidae are, at present, very difficult to determine to species, a method of collecting adult insects was used. An inverted funnel trap was employed to collect the adult insects. During the summer of 1951 at the Lake City Experiment Station insects were trapped from each of the six experimental ponds. The insects collected were classified to species and verified by members of the United States National Museum. The following discussion compares the fertilized and un- fertilized ponds as to quantitative and qualitative produc- tion of members of the family Tendipedidae. . 11l|l|llll|||n II LITERATURE REVIEW The family Tendipedidae has been studied extensively in Europe for many years by such.prominent workers as Brundin (1949), Goetghebuer, and Thienemann, to mention only a few. These workers have focused their research on the correlation of midges with lake type classification and have also re- ported extensively on.midge biology. In the United States the work with the family Tendipedidae centers around Johann- sen (1934), (1957a), (1937b); Malloch (1915), (1917) and Townes (1945), who were primarily interested in classifica- tion but have added pertinent information on biology and ecology of the midges. The use of fertilizer in pond management was extensively investigated by Smith and Swingle (1939), (1947), (1950),; Howell (1942) and others in the southern states with.phenom- enal success. Tack and Morofsky (1946) began an investiga- tion of the effects of fertilizer in a northern climate. Ball (1948), (1949) and Ball and Tanner (1951) have recently concentrated their studies on pond fertilization.with.special emphasis on fish.production. From the conclusions of many of these investigations it is obvious that one of the organisms significantly increased by fertilization is the midge. The midge has been equally important as a fish.food organism.as it has been reported consistently in the stomach of many fish (Clemans, Dymond, and Bigelow, 1924). The purpose of this study was to discover which species of midges were increased by fertilization and to investigate the life history of these species. III OBJECTIVES The overall objective was to study one step (midges) in the complex food chain which.exists in the biological pro- duction of ponds. The immediate Objectives were as follows: 1. 2. 3. Compose a check list of the species of Tendi- pedidae and Heleidae present in the experimental ponds. Test the workability of a specially designed adult insect trap as a quantitative and quali- tative insect'sampler.’ Compare Tendipedidae populations of ponds fer- tilized at different rates as to number of species of insects present and make a quanti- tative comparison of these insects. Compare shallow ponds with deeper ponds as to number of insects and species present. IV EXPERIMENTAL STUDIES A. Description of the Ponds The ponds at which this investigation was undertaken are located at the Michigan State College Lake City Experiment Station. This is located in the north central section of the lower peninsula of Michigan in an area where the winters are very severe, having continuous periods of exceedingly low teme peratures and considerable snow deposits. The construction of the ponds was begun in the fall of 1945 and was completed in June 1945. Ponds ”A" and ”B" have a surface area of approximately one-half acre, while ponds ”E“ and "F" are somewhat smaller with a two-tenths acre surface area. "The maximum.depth of ponds "A", "B“, "E", and "F" is about six feet. The other two ponds used in this experiment, "C" and "D", have a surface area of about 1,500 square feet. .The maximum.depth of pond "C" is one and one-half feet and of pond "D" is two and one- half feet. ‘ Ponds "A", ”B", "E", and ”F" were constructed by removing a surface deposit of muck exposing a sandy soil bottom. The dykes were built by bringing in clay and other fill. Ponds 'C" and "D" were pits which remained after fill had been removed. Ponds "A", "B”, "E“, and I‘F" are equipped with inlet and outlet structures .mh‘mk. 1i: possible to drain and refill the ponds. The water supply for these ponds consists of a reservoir which.was built by constructing a dam.across a small 5 stream.known as Mosquito Creek. It is possible to eliminate all flow of water through the ponds during periods of inves- tigations. The water supply for ponds "C" and "D” is taken entirely from the seepage of subsurface water with a small amount of run-off water enteringthe ponds. Ponds "C" and "D" have no inlet or outlet. The only way the water may be removed is by pump. ‘ f Pond "A" has been used exclusively as a check for the fertilization experiments carried on by Tack and Morofsky (1946). It has never received any fertilizer. The water in pond "A" remained very clear until the second week in.August when some turbidity was observed. However, it was consis- tently clearer than pond "B” which.will be discussed later. There was no rooted vegetation in pond "A” and all algae \f/ present was of a planktonic nature. The dykes of pond "A", like those of all the ponds, have been planted with Reed Canary Grass which is the principal plant found within sev- eral feet of the water. Doctor Peter I. Tack found that by planting Reed Canary Grass, the washing away of dykes by wave action.was almost completely eliminated. Pond ”B" is a pond very similar to pond "A" in.many respects. Hewever, pond “B” has been fertilized very heav- ily and extensive blooms of planktonic algae were present at all periods during the investigation. There was no rooted or floating vegetation in pond "B". Plankton samples were taken at ten-day intervals throughout the summer and the plankton increased in pond 'B' until August 1 when it reached its peak; 6 at this time it was eight times as prevalent as the bloom in pond “A". At the peak of the plankton bloom in pond ”B" it was impossible to see a white object at a depth.of two and one-half inches. The application of fertilizer in pond "B" was at the rate of 100 pounds of 10-6-4 N-P-K to the acre on August 9. ‘A11 fertilizer was broadcast by hand over the pond surface. Both ponds "A" and "B" contained 289 Northern black bullheads Ameiurus melas.mglag (Rafinesque) which.hadan average weight of six ounces. These were the only fish stocked in the ponds. However, there were fathead minnows Pimephales promelas premelas_(Rafinesque) and Northern red- belly dace Chrosomus eos (Cope) present. It is most probable that these minnows entered the ponds through the inlets. During the summer of 1951 in both.ponds "A" and "B“, the pro- duction of young fish.was very great. At the end of the growing season schools of young bullheads were abundant and many young minnow fry were observed. The bottom of both.ponds “A" and ”B" was covered with a soft organic ooze to a depth of two to six inches. This material was distributed evenly over the bottom to within three feet of the shore where it gave way to a sandy, wind swept shoal area. . Pond "C", as previously stated, is one of the shallow ponds and has been set aside as check similar to pond "A". Pond "0" had no higher aquatic vegetation except around the margin where several small willows were intermingled with grass, clover and sedge. The bottom.of pond "C" was very 7 firm.and of a clay nature without any organic deposit. Pond "C" has remained unfertilized and it has been consistently low in productivity (Bray, 1949). The water in pond "C" was turbid but this turbidity was due to inorganic colloids present in the water. Pond "D", the fertilized shallow pond, had a dense phy- toplankton bloom throughout the summer season. The water was a deep green color and was exceedingly rich in small inver- tebrate organisms such as the immature stages of insects, scuds and zooplankters. Pond "D", like pond “C", was en- tirely free of rooted vegetation. Duckweed, £9293 sp., was present near the shore. The bottom of pond “D" was covered with an organic ooze similar to ponds "A" and "B” and this ooze was of a pulpy peat nature (Roelofs, 1944). Several places in the pond this ooze reached a depth of eight inches. Five pounds of 10-6-4 N-P-K fertilizer was applied to pond "D" on June 22, July 12 and August 9. There were no fish in either pond ”C" or pond "D” during the summer of 1951 while the experiment was being conducted. Pond "E" is a pond which has been very inconsistent in its reaction to the application of fertilizer. It has never passed through the biological chain of events which eventu- ally leads to the formation of dense plankton blooms. Pond "E" had a dense growth of QEEEELSP' which.was intermingled with.Spirogyra sp. Often during extended periods of warm, bright weather the growth.of th£§.sp. and Spirogzra sp. would rise to the surface, due to the formation of excess oxygen, and remain there until cool, cloudy weather when it would settle to the bottom. This cycle was repeated sev- eral times during the summer of 1951. Several investigators (Patriarche and Ball, 1949; Swingle and Smith, 1950) have ob- served that in some ponds it is very difficult to get a plank- ton.bloom and that in these cases the fertilizer increased the production of filamentous algae rather than the planktonic type. The water in pond "E" was extremely clear at all times and it was possible to see the movement of organisms on the bottom at a depth of five and one half feet. The fish.popu- lation of pond "E" consisted of 53 large black bullheads Ameiurus mglag.mglag (Rafinesque) with an average weight of 20 ounces and a few Northern redbelly dace Chrosomus eos (Cope). When the pond was drained in.August only three of the large bullheads remained. The most significant ex— planation for the mortality of the bullheads was the fighting which occurs during the breeding season (Adams and Hankinson 1928). Twenty pounds of 10-6-4 N-PeK fertilizer was added to pond "E" on June 22, July l2 and August 9. The biological community which existed within pond "F" was very unusual and did not follow the typical fertilized pond biota. The plankton was abundant all summer in pond "F" but it never reached the density of the bloom of pond “B". The first time a significant bloom occurred was in the sum- mer of 1950 and perhaps in succeeding years it will continue to multiply. On the bottom of pond "F" were numerous col- onies of Nostoc sp. balls. This is the only pond where this alga was present and there appeared to be no satisfactory explanation as to why this phenomenon occurred. The bottom of pond "F" was not as homogeneous as the other ponds for the deepest deposit of organic material was in the narrow east end and the remainder of the pond had the organic ooze mixed with gravel. During the fall of 1950 gravel was spread over the west half of this pond to fill several low spots which interfered with draining operations. There was a very large population of minnows in pond "F" in May and they reproduced very successfully during the summer so a large number of fish were present all during the experiment in this pond. The following species of minnows were present in pond "F": northern redbelly dace Chrosomus eos (Cope), western golden shiner Notemigonus crysoleucas auratus (Rafinesque), common shiner Notropis cornutus (Agas- siz), northern fathead minnow Pimephales promelas promelas (Rafinesque) and there were a few black bullheads. Pond "F" received 20 pounds of 10-6-4 N-P-K fertilizer on June 22, and July 12 and on August 9 ten pounds were broadcast over the pond. A number of comments may be given in regard to general operation of the ponds during the experiment. Doctor Peter I. Tack was carrying on simultaneously an experimental cper- ation with fish production and this made it necessary to drain the ponds in May and again in September to remove the fish. 10 The ponds were never completely exhausted of water and they were refilled the same day drained, thus it was unlikely the draining had a serious affect on the insect production. The only water which left the ponds during the experiment was through seepage and evaporation and to compensate for this a small amount of water was allowed to enter the inlets. B. Description of the Trap The trap used to sample the adult insects was a modi- fication of one used by Brundin (1949) in southern Sweden. The trap consisted of an inverted funnel which sampled a one square yard area (Plate I, Figure 1). The diameter of the larger opening of the funnel was 41 inches and it tapered to a 3%“inch neck. The distance from the bottom of the funnel to the top of the trap was twenty inches, including the neck which was 2% inches. At the top of the trap a 3% inch Kerr type ring was soldered in place; to this was screwed a two quart fruit Jar (Plate I, Figure 2). A paper cup, with.a hole cut in the bottom, was placed within the neck of the fruit jar and scotch tape was used to keep this in place (Plate I, Figure 2). The trap was built of sheet metal with all Joints soldered and around the bottom of the trap a heavy wire was built in to keep the trap rigid. A line was connected to the two quart jar and a buoy was fastened to the other end of the line. As the insect pupae moved to the surface to emerge as adults they first came in contact with the funnel and worked 11 their way up the sides of the funnel and eventually emerged in the Jar which was partially filled with air. The paper cup which was inverted in the neck of the jar prevented the insects from resting on the surface film.and gave them a place to rest as they dried their wings and body. Some workers using this type of trap have not found it necessary to include an extra retaining device in the jar. In this study it was quite apparent that the insects often became trapped in the surface film and the entire sample was in such devastated condition that it could not be classified until the paper cup was included in the operation. This type of trap appeared to have several very com- mendable attributes. The trap collected adult insects which at the present time are much.easier to identify than the immature forms. The trap gives a quantitative comparison of production when comparing several bodies of water. The pupal exuviae may be collected and associated with the adults. The one disadvantage is the large size and heavy weight. In this investigation weight was not an important factor as the traps were moved only short distances but if the traps were to be transported often they might be constructed of metal net as Brundin (1949) used and sample only one-fourth square yard. The tent trap used by Miller (1941) is a trap which might be used to collect similar data and perhaps it could be constructed with less expense. It is questionable whether the insects could be removed as quickly and easily from the tent as from the Jar. The use of adult insect samplers is 12 not a new idea for it was used as early as 1905 in the United States by Needham.(1908) and several other workers have re- cognized the advantages of this type of insect sampling de- vice (Adamstone and Harkness, 1925; Ide, 1940). C. Sampling of Adult Insects The following equipment was used in sampling the adult insects: inverted funnel trap, waders and cyanide killing jars. Three samples were taken each week from each pond. To be as impartial as possible the traps were placed at dif- ferent positions on the bottom of the pond each time a sample was taken. All depths were sampled since the traps were shifted back and forth from.ehallow water to the deeper water in the center of the pond. The traps were placed in the ponds at one o'clock p. m. and remained in the ponds for the succeeding twenty-four hours. The following procedure was followed in placing the traps in the pond and removing the insects after twenty-four hours. First the paper was scotch taped in the Mason jar and the jar was screwed on the funnel. By the use of waders the trap was taken out into the pond where the sample was to be taken. The trap was carefully eased into the water and when the air in the big funnel had been displaced by water it was lowered toward the bottom of the pond (Plate II, Figure 2). Two important precautions should be injected here. First, the trap should be lowered in an upright position to 13 keep the two-quart jar dry. Second, the trap should rest evenly on the bottom in an upright position. If the trap was operated on a lake it need not rest on the bottom. Hew- ever, in ponds of five feet it operated most efficiently on the bottom. No matter at what depth the trap is to be placed the jar should be under the water to eliminate the condensa- tion of moisture on the inside of the jar. At one o'clock the following day the trap was carefully raised from the bottom and moved toward the shore, being ex- tremely careful to keep the funnel submerged to prevent the loss of specimens. The jar was loosened and a lid slid over the opening (Plate 3, Figure 2); this was done without turn- ing the jar over and it proved to be a very effective way of holding the insects. The jars were taken into the laboratory and a cyanide bottle was placed in the mouth of each.jar and allowed to remain there until all specimens were asphyxiated. D. Light Trap A New Jersey light trap was operated the same night a funnel trap sample was taken. This was done to compare the effectiveness of the light trap with the funnel trap in midge sampling and to give additional specimens for labora- tory study. The light trap (Plate II, Figure 1) attracts the midges by means of a loo-watt bulb and is provided with a fan which blows them.into a killing jar. The light bulb and fan are l4 fastened to the inside of a large cover, which sheds rain, and a funnel is below the fan, fastened to three legs that support the trap when it is placed on the ground. The midges taken from the light trap corresponded very closely to those removed by funnel trap sampling. It appeared that for taxonomic work the light trap would be a very effec- tive way of collecting specimens. E. Laboratory Procedure The following equipment was used in processing and classifying the insects in the laboratory: dissecting mi- croscope, dissecting tools, slides, cover slips, absolute ethyl alcohol, diaphane solvent, diaphane and.minuten nadeln. After the insects were dead they were removed from the jar and spread on a white sheet of paper. It was found that by classifying and pinning the specimens within 24 hours after they were taken from the ponds they were much easier to work with and the characteristics used in species deter- mination were more pronounced.' The insects were first sorted macroscopically as far as possible toward species determination. The insects were then examined under a dissecting microscope and in most cases it was possible to separate the different species with- out further operations. The first time a new species was observed a slide mount was made of the genitalia of the male; this was also done whenever species determination was doubtful. The following 15 is a summary of the technique used in.making the genitalia mounts (Townes 1945). If the specimen is dried out it is placed in a relaxing jar for several hours. The terminal third of the abdomen is then clipped off with a pair of fine scissors. The clipped-off part is then placed in a test tube of 10 percent sodium hydroxide and placed in a boiling water bath for eight to ten minutes. The specimen is then transferred to a watch glass of water and then to a watch glass of 95 percent ethyl alcohol. After several minutes in this solution it is transferred to a microscope slide. 0n the slide it is turned right side up, the excess alcohol is drained off, and is covered with diaphane solvent. The final process is the covering of the specimen with.diaphane and then easing the coverglass into place. It is of upmost importance to give the slide and the pinned specimen a cor- responding number so they can always be associated. After all the specimens from a pond for a particular day were classified and recorded a number of specimens rep- resenting each species were pinned and placed in insect trays. The remainder of the insects were preserved by plac- ing them.in small vials and a crystal of paradichlorobenzene was added. All insects were preserved in this way and it proved to be a very wise procedure as all of the specimens were available for recounting or comparison at the end of the experiment. 16 V NOMENCLATURE The principal references used in classifying the pro- minent groups are listed below. TENDIPEDIDAE (Chironomidae) Subfamily Tendipedinae a. Johannsen (1905), (1957) b. Malloch (1915), (1915b) 0. Townes (1945) d. Hauber (1944), (1947) Subfamily Pelopiinae a. Hauber (1945) b. Hauber and Morrissey (1946) c. Morrissey (1950) d. Malloch (1915) e. Townes (1945) Subfamily Hydrobaeninae a. Townes (1945) HELEIDAE (Ceratopogonidae) a. Malloch (1945) b. Thomson (1957) CULICIDAE a . Maths son (1944) 17 Townes'(1945) work was used almost exclusively for the preliminary classification of the subfamilies of Tendipedidae and it was the most frequent reference used in specific determination of the tribe Tendipedini. When difficulty arose in the classification of female specimens, Malloch's (1915) work was useful. For verification of the insects they were shipped to the United States National Museum, washington D. C. A complete sample of all species were first identified and genitalia mounts made of all specimens; they were then packed and sent to the museum. Doctor Alan Stone verified the species of Tendipedidae and Culicidae and the Heleidae were determined by Doctor W. W.‘Wirth. The returned specimens provided a very valuable check list for all the insects sampled. Before the final tabulation was compiled all insects were compared with those verified by the experts at the museum. This pro- cedure worked out very satisfactorilyin handling large num- bers of insects with the greatest accuracy possible. Until the publication of Townes (1945) appeared, the family Tendipedidae had always gone under the name Chironomr idae and the most important genus Tendipes was known as Chironomus in.American and British literature. Much of the European literature is based on the genus name Tendipes and it appears that Townes adoption of this name follows the rules of nomenclature and will eventually standardize the nomenclature for this group of insects. In this paper the nomenclature of Townes and that of the United States National Museum was used exclusively. TENDIPEDIDAE 18 VI A LIST OF INSECTS RECOVERED FROM THE FUNNEL TRAP SAMPLES Tendipedini 1. 2. s. 4. 5. e. '7. e. 9. 1o. 11. 12. 1s. 14. 15. 16. 17. 1e. 19. 20. 21. Tendipes brunneipennis (Joh.) Tendipps staggeri (Lundb.) Tendipes modestus (Say) Tendipes plumosus (L.) Tendipes nervosus (Staeg.) Tendipes decorus (Joh.) Cryptochironomus digitatus (Mall.) Cryptochironomus fulvus (Joh.) glyptotendipes paripes (Edw.) glyptotendipes lobiferus (Say) Pseudochironomus banksi (Townes) Tanytarsus nigricans (Joh.) Lauterborniella varipennis (Coq.) Microtendipes pedellus var. pedellus (Deg.) Paratendipes albimanus (Mg.) Pglypedilum.nubeculosum (Mg.) Polypedilum.simulans (Townes) Harnischia viridulus (L.) Harnischia tenuicaudata (Mall.) Kribioxenus bicornis (Townes) ngytarsus punctipes (Wied.) 19 TENDIPEDIDAE (Cont.) Pelopiinae 1. 2. Procladius bellus (Lw.) Procladius guliciformis (L.) 5. Pelopia punctipennis (Mg.) 4. Pentaneura spp. Hydrobaeninae 1. 2. 5. 4. HELEIDAE l. 2. 3. 4. 5. CULICIDAE Cricotopus trifasciatus (Panz.) Cricotopus brunnicans (walley) Cricotopus spp. Hydrobaenus spp. Atrichopogon levis (Coq.) Jenkinshelea albaria (Coq.) Bezzia glabra (Coq.) Bezzia sp. Dasyhelea sp. near traverse (Thomson) Chaoborinae 1. Chaoborus punctipennis (Say) VII DISCUSSION A total of 174 square-yard samples were taken between June 15 and September 10 from the six experimental ponds. In ponds "C" and "D" one-fifth.of the bottom area was sampled and in ponds "a", "B", "E" and "F" a smaller per- centage of the bottom area was covered by the traps. The traps were placed in each pond 29 times during the experi- ment and allowed to remain there for 24 hours. A total of 261 square feet of bottom was sampled in each pond during the summer of 1951. There were 5,852 insects representing 55 species taken from the six ponds or an average of 55.5 insects per sample. It is important to remember that these samples represented the emergence of adult insects over a 24 hour period and had no relationship to the standing crop or to the number of immature organisms in the pond. The term."yie1d" as outlined by Clarke (1946) would very con- veniently cover this group of insects which was taken by the traps. This report is restricted to the order Diptera of which the following three families were represented: Ten- dipedidae, Heleidae, and Culicidae. A. Relative abundance of various subfamilies The family Tendipedidae made up 91.7 percent of the total number of insects sampled. There were 29 species of Tendipedidae sampled belonging to the following subfamilies: loseaoaaso. u A gun—Q3523 ho umuqsaau 8.3. a H a one was so on n o a oocasoooceo - . . leafless. m e oa H a a a oceaoaom a n ea 0 o n n a o ocsacosoooeam. non aaea sea vow ea no em on om use so . «on «casaoooaoaso on an as on. m oa e. .o av on am (wad ocsaaaoaoo Has .Haa. .co on co on ea NH one so. use see acaeooaecoa one: season sac: oasaou odd: cannon oasa.oflcaoa one: oaosou can: oHo-oa .— esoa a econ. a secs 0 econ u uses 4 econ seasoned. ITION 0F SUBFAMILIES FIGU OS PERCENTAGE COMP \\‘ S O O O fi' :0 N $1038?“ $0 “3083:! (nmvs) 3V0l3'13H 3VNIN3VGOBOAH 3VNIHOGOVHO 3VN|Id013d . lNIOBdIONBi lNIHlOBSdO'IVO 25 Tendipedinae, Pelopiinae and Hydrobaeninae. Figure 1 shows the percentage composition of the different groups sampled and from this it is apparent that 60 percent of all insects were members of the tribe Calopsectrini. B. Tribe Calopsectrini The tribe Calopsectrini is an exceedingly difficult group of insects to work with due to the following two rea- sons. First, the tribe Calopsectrini has never been classi- fied to genus or species. Second, there is a noticeable absence of literature pertaining to the Calopsectrini. It was very easy to separate, by the use of color and other characteristics, the members of this group into subgroups. These subgroups were probably different species but since no keys were available to classify them, this practice was dis- continued and the group was treated as a tribe only. There were 5,165 specimens belonging to the tribe Calop- sectrini collected and of these 80 percent were females. A constant ratio existed between.ma1es and females throughout the season with the females always in a significant major- ity. These specimens were separated very carefully and there appeared to be no explanation for this unusual occur- ance. The distribution of the tribe Calopsectrini as to ponds was equally as unique. Fertilizer did not increase the production of this group, in fact the greatest produc- tion was in the ponds fertilized at a low rate. Pond "F" produced 52 percent of the Calopsectrini collected, while 24 pond "B", which.was very productive in Tendipedini, produced only 9 percent. The part the tribe Calopsectrini played in the bio- logical cycle which was taking place in the aquatic environ- ment of these ponds is scarcely understood. There is no re- port of the tribe Calopsectrini being represented in bottom. samples or adult sampling devices, although, they were the most numerous group of insects emerging in this study. It seems probable that they were present in similar habitats but may have been overlooked or included with other groups. The small size of these insects may account for their ab- sence in many samples. The maximum length of the adult Calopsectrini was four millimeters and it was surprising to observe that all insects belonging to the tribe Calopsectrini were almost the same size. There was no way of investigating how many of the small larvae and pupae of these insects were taken as food by minnows. They would be digested very rap- idly by a fish since they were so very delicate. Several attempts were made to sample the bottom of pond "F" with.an Ekman dredge to recover some of the larvae but in all in- stances it was impossible to see the larvae, even by the use of a dissecting microscope. The emergence of the members of the tribe Calopsectrini was very constant throughout the summer without any cyclic variations. It appeared as if there were several genera- tions emerging during the investigation but until species are better known it will be difficult to determine the hump 25 bar of generations. There were many questions unanswered in the survey of the tribe Calopsectrini and the opportunities for further research are abundant. The tribe Tendipedini made up 27 percent of all insects collected and might be elaborated on at this point. However, the principal objective of this project was to study the tribe Tendipedini, so a complete chapter will be devoted to the discussion of this tribe. C. Subfamily Pelopiinae There were 552 specimens belonging to the subfamily Pelopiinae sampled, representing 9 percent of the total pro- duction. Three genera were represented with at least five species taken. It was impossible to identify several of the species, so the discussion will be limited to the three identified species. In the subfamily Pelopiinae there was no significant in- crease in the fertilized ponds. Pond "A", the check pond, produced 59 percent of the Pelopiinae taken. Pelopia pang; tipennis (Mg.) made up one half of the Pelopiinae specimens taken from.the traps. Pelopia punctipennis (Mg.) had two definite periods of emergence, one occurring the last week in July, the other the last week in August. Procladius bellus (Dw.) followed the emergence curve shown in Figure 2 and it is quite possible this species has two generations a year like many of the Tendipedini. The other species of Pelopiinae had an erratic emergence and were so seldom. 26 sampled that little information as to life cycles could be gathered. Several investigators have published reports on the classification of the subfamily Pelopiinae but the literature has a noticeable absence of ecological notes. Hauber (1945) states that most species are carnivorous and quite commonly cannibalistic. Leathers (1922) reports of one species killing its prey, which.very often includes large numbers of diatoms, and sucking the contents. Most workers are unanimous in their reports on types of habitat most often associated with the Pelopiinae. They report the immature stages most fre- quently occurring in shallow ponds and slow’moving streams. The ponds studied appear to be well suited to Pelopiinae production as the food habits and ecological requirements were present. D. Subfamily Hydrobaeninae There were 48 specimens collected belonging to the sub- family Hydrobaeniane and these insects were included in two genera. It was possible to identify two species and several other specimens were classified only to genus. Nearly one-half of the specimens of Hydrobaeniane were taken from pond ”E" and of these Cricotopus trifasciatus (Panz.) predominated. Johannsen (1937) reports the larvae of Cricotopus trifasicatus (Panz.) was normally associated with pond lilies and Elodea. Pond lilies and Elodea were not present in pond “E" but there was the extensive growth of §h§£§_sp. and Spirogyga sp. in which this species may have 27 lived. Not enough specimens were collected to establish what effect fertilizer had on the subfamily Hydrobaeninae. In this study the members of the subfamily Hydrobaeniane were most prevalent in the ponds with.a growth of filamentous algae and were very scarce where plankton was abundant. E. Family Heleidae Only 21 specimens were collected belonging to the family Heleidae and of these 15 were taken from pond "E". Thomson (1957) reported that many of the aquatic Heleids which she collected were taken from blanket algae. Pond "E" had an extensive growth of filamentous algae and evidently provided the type of habitat necessary for Heleid production.. The emergence of the different species of the family Heleidae was restricted to a very limited period. Each.time a species was taken it showed up in only one sample. The family Heleidae and the subfamily Hydrobaeniane were very similar in total production, response to fertilizer and habitat pre- f erred. F. Family Culicidae The family Culicidae was restricted to one species, Chaoborus punctipennis (Say) belonging to the subfamily Chaoborinae. Chaoborus punctipennis (Say) was restricted almost entirely to the shallow ponds. Ponds "C" and "D" pro- duced 97 percent of the specimens collected. This is in direct contrast to the reports of Welch (1955) and Horns 28 (1957), as they found the abundance of Chaoborus at a depth of 50 to 55 meters. Chaoborus punctipennis (Say) appeared to prefer the environment of the fertilized pond, as 80 percent of the specimens collected were taken from pond “D". This evidence is substantiated by Bray (1949), as he found the larvae of Chaoborus_punctipennis (Say) to be restricted to the fertilized pond. The peak emergence of Chaoborus punctipen- gig,(Say) was confined to two periods, one June 15 to June 22 and again between July 26 and August 14. During the remainder of the season only occasionally was a specimen collected. The reason pond "B" produced so few specimens, even though it was heavily fertilized, is not well understood. One explanation for this low productivity may have been that the fish in pond "B" consumed sizeable numbers of Chaoborus. There is no agreement in the literature as to the importance of Chaoborus as a fish food organism. Herms (1957) reports as many as 100 of these insects were found in the stomach of one "calico bass" a species of fish.which feeds near the bot- tom ooze where the larvae occurs, principally during the winter. In contrast to this, Howell (1941), Ball (1948) and Patriarche and Ball (1949) observed that Chaoborus was not taken by the bluegill. There are no reports of ChaOborus being taken by bullheads but there is also an absence of stomach analysis through.the winter months. It is possible that Chaoborus may have been reduced in this way. 29 G. Other Insects Sampled Since the project was established primarily as a study of the midges, other groups were not classified to species. There were eight specimens of Trichoptera and nine of Ephe- meroptera taken from.the samples. There appeared to be some (adjustment needed in the trap to allow the mayflies to emerge successfully, especially those of the genus Caenis. In pond ”F" there was a large population of mayflies be- longing to the genus Caenis. These insects would come up into the jar but were unable to get out of the water to com- plete the subimago stage and eventually emerge as adults. The trap appeared to sample the Trichoptera success- fully but this order was poorly represented in the ponds. Two specimens of the family Cecidomyiidae were recovered from a sample taken in pond "C". The trap appeared as if it would be equally as useful in sampling other aquatic orders, if they were present, as it was in collecting midges. H. The Tribe Tendipedini 1. Seasonal Variation The seasonal variation of Tendipedini collected from all ponds is shown in Figure 2. The curve of insect emer- gence is based on the total number of Tendipedini taken during each.samp1e. (The circles on the graph represent each.time a sample was taken. If more samples could have been taken the curve would have taken on a smoother appear- 30VHO|1N30 $338930 CD If) V '0 N -— 'Q a, Q N c N N N N N N N — — .— -- I I I 1 POPULATION FIGURE 2 SEASONAL VARIATION OF TEHPERATURE AND TENOIPEDINI T l r l I I I I . : . ' 2 H < I: _ O- 8 E’ a 2" c E x - £ 3 2 .. r.- s r- E e 3 z 4 til I «1 <2 ”:1 - ~ 8 \‘ d ‘L_-- —:3' \~-- - 9 12:» . <""‘ n“ .l g a-‘_- -—J -"-'------J . O (p N .-“ . \‘\ l l l l l l I L l l A I A 9 O O o O 8 I0 0 - 8 o '0 n N N — - SlOBSNIiO 838WON SEPT AUGUST JULY JUNE 31 ance, however, the effects of sudden temperature changes on insect emergence shows up very clearly. Surface water temp peratures were taken at eight in the morning and at five in the afternoon each day and the temperature curve is plotted fram the average of these two temperatures. There was one period when the emergence of Tendipedini, as a group, was exceedingly great. This emergence began about July 20, reached its peak on August 20 and rapidly de- clined during the succeeding ten days. The water tempera- ture dropped seven degrees during the first week in.August. The Tendipedini emergence fell in direct proportion to the water temperature decline. The water remained cool for two weeks but the emergence of insects rapidly increased until the peak emergence was reached. Each.time a sample was taken it was apparent that there was a direct correlation between rise and fall in water temperature and insect emer- gence. The variation of insect emergence was not as sharp a fluctuation as the temperatume change. It appeared that the emergence operated within limits of temperature vari- ance. The rise or fall in temperature would only serve to increase or decrease the emergence for a certain day and would be compensated for in the following samples. a very excellent example of this occurred on.August 22 when the temperature dropped sharply and the following sample res- ponded to this decrease. The insects increased sharply in the sample taken the next day, although the temperature was still relatively low. 52 On weekends during April and May observations were made on the ponds, although.no samples were taken. It was very evident that a tremendous emergence of Tendipedini occurred the first week of May. At this time there were large rafts of pupal exuviae on the surface of pond "B" similar to those present in August during the large emergence. It seems safe to conclude that there were two generations a year of the predominate Tendipedini species in the experimental ponds. Bray (1949), working on the same ponds with the larval forms, reported a conspicuous decline in his midge samples between.August l and September 1. This decline corresponds favorably with the emergence of adults in this study. Ball (1948) reports the same type of decline in larval abundance in bottom samples but the drop is somewhat earlier in the season. This perhaps can be explained, as his experiments were conducted in the southern section of Michigan where the growing season is considerably longer. This discussion of emergence and number of generations is including all of the species of the tribe Tendipedini. Not all of the spe- cies followed this cycle but the species which were present in large numbers and those responding most actively to fer- tilizer did follow this emergence curve. Those species which were exceptions to the curve will be discussed sep- arately in the succeeding chapter. 2. Variation of Pond Populations This discussion of variation in production of the dif- 53 ferent ponds will be restricted to the tribe Tendipedini, since the other groups were discussed in a previous chapter. Figure 3 shows the percentage distribution of Tendipedini in each pond. In comparing pond "B", the heavily fertilized pond, with pond "A", the check, it was apparent that for every midge produced in pond "A", three were produced in pond "B". Since the two ponds have similar histories and were very much alike except for fertility, it would seem that this in- crease in midge production was due to the application of fertilizer. Figure 5 shows that both ponds "E" and "F", the other two fertilized ponds, were lower in Tendipedini production than the check. This data is in complete contradiction with that from pond "B" where fertilizer appeared to increase production. Several substantial explanations were avail- able to clarify this low productivity in ponds "E" and "F". Ponds "E".and "F" have received considerably less-fertilizer than "B" and they have been very slow in the biological response to fertilizer. Pond "E" has not produced a plank- ton bloom and 1950 was the first season that pond "F" pro- duced any significant phytoplankton. The majority or the insects produced belonging to the family Heleidae, sub- family Hydrobaeniinae and tribe Calopsectrini were taken from ponds "E" and "F". In this study it appeared that where these three groups were the principal insects emerging, the species of the tribe Tendipedini were exceed- d .d d d 0 O O 0 on nu “u" nu nu nu nu nu J 3 O O .\\\ \n\\ \\\n\ "H" ou“\““\ xmn.mn ,nm,nn .\\“\\“u Jrlmll .r pl _\\\\\\_ .nAnn‘.“_ “IHIIHI .1 Ill] 1,1, I .1, III .rlvrl ozoa owNSZENm g 344:» 7/////. 3.5238 mozoa >m m...owmz. u o 20:30.3...90 uo