A Study of the Population of Insects Emerging as Adults from the Dundas Marsh, Hamilton, Ontario, During 1948

Abstract

Between Mar. 16 and Nov. 20, 1948,15,338 insects emerging from waters of Dundas Marsh were trapped in 5 cages, representing an avg. emergence of 409 insects per sq. ft. Orders represented were Ephemeroptera (9.9%) - one family; Odonata (1.5%) - 4 families; Trichoptera (0.5%) - 3 families; Lepidoptera (0.9%) - 1 family; Diptera (87.1%) - 12 families and Hymenoptera (0.1%) - 2 families. Midges (Tendipedidae) constituted 92.5% of Diptera. Times of first, last and max. emergence of each sp. were recorded. Seasonal variation in emergence of numbers of spp. was correlated with changes in temp, of water, day of emergence of max. numbers of spp. being preceded by day on which max. temps were recorded at all cages.