Studies of the Byron Bog in Southwestern Ontario. XII. A Study of the Population of Insects Emerging as Adults from Redmond's Pond in 1957

Abstract

Between March 23 and October 4, 1957, 13,159 adult insects were trapped in five tent-traps set out on the pond on water up to 3 ft. deep. Ihe orders represented were Ephemeroptera (0.02%), Odonata (0.12%), Trichoptera (0.3%), Hemiptera (0.02%), 'Coleoptera (0.04%) and Diptera (99.5%). Midges of the family Chironomidae constituted 78.3% of the Diptera and 'Culicidae 21% of the Diptera. Other families of Diptera were Tipulidae, Ceratopogonidae, Dolichopodidae, Simuliidae, Tabanidae, Ephydridae and Muscidae. Families of Coleoptera were Helodidae and Chrysomelidae. The numbers and seasonal occurrences, including times of maximum emergence, are reported for each species. In 1956 a collection of insects emerging from Redmond's Pond in the Byron Bog was made by trapping the insects in a floating tenttrap (Judd, 1958b). In 1957 a second study of the aquatic insects of Redmond's Pond was undertaken using five tent-traps set out on the pond. The present paper is a report on this study. Acknowledgment.-The writer gratefully acknowledges the assistance of Mr. R. B. Catalan who aided throughout the summer of 1957 in collecting insects from the traps, in sorting and counting specimens and in recording data. Much of the data were assembled while the writer held a Summer Research Associateship of the National Research Council in 1957. DESCRIPTION OF COLLECTION SITES Redmond's Pond is situated in the northwest corner of the Byron Bog as shown on the map accompanying the description of the bog (Judd, 1957b). It is completely surrounded by the sphagnum mat which forms the center of the bog, and the bushes of leatherleaf, Chamaedaphne calyculata, which grow in the sphagnum, have their branches extending out over the water of the pond. In 1957 the pond was 240 feet long in the north-south direction and 160 feet wide at its greatest diameter (Fig. 1). The water depth remained almost constant during the summer and nowhere on the pond was it more than five feet. The bottom of the pond was covered with loose, brown peat. No attempt was made to measure the depth of the peat in 1957, but Woolverton (1900) found that the peat in the center of the Byron Bog was at least 60 feet deep. The surface of the pond was devoid of vegetation in 1957 except in small bays around the circumference. 1 Contribution from the Department of Zoology, University of Western Ontario; a project supported by funds from the Ontario Research Foundation and an operating grant from the National Research Council. 89 This content downloaded from 157.55.39.70 on Tue, 06 Sep 2016 06:16:50 UTC All use subject to http://about.jstor.org/terms 90 THE AMERICAN MIDLAND NATURALIST 65(1) On March 14, 1957 the pond was still completely covered by ice and by March 16 all the ice ihad melted away. Thereafter light shell ice formed on the water at the edge of the pond on cooler nights during March. On March 23 traps 1, 3 and 5 were set in position at locations around the edge of the pond, and on March 30 traps 2 and 4 were set in position in the deeper water toward the center of the pond (Fig. 1). Location 6 on the map is the site at which the single trap was anchored in 1956. Each trap was kept in its one position during the season by a rope anchored at one end to bricks on the bottom of the pond and stapled at the other end to the side of the trap. The inside dimensions of each trap were 2 ft. x 2 ft. so the trap covered 4 sq. ft. of water surface. The traps were kept in position until October 4 when collections were discontinued. Thin shell ice formed at the edge of the pond on that day. Trap 1 was located in a small bay in the north-east corner of the pond surrounded by bushes of leather leaf and on water 2 feet deep. Rooted vegetation in and around the trap comprised Spatterdock, Nuphar advena (Ait) Ait. f. and Bladderwort, Utricularia vulgaris L. Floating on the surface was a sparse accumulation of fronds of Duckweed, Lemna minor L. and Water Flax-seed, Spirodela polyrhiza (L.) Schleid. Trap 2 was located in the center of the pond on water 3 feet deep where there was no vegetation. Trap 3 was located at the west edge of the pond in water 2 feet deep where rooted plants of Utricularia vulgaris were present and a few fronds of Lemna minor and Spirodela polyrhiza floated at the surface. Trap 4 was toward the center of the pond on water 3 ft. deep Fig. 1.-Map of Redmond's Pond o a4 ( showing location of the five tent-traps (1-5). Location 6 is the site of the trap on the pond in 1956.