Life history and bionomics of Arctopsyche grandis (Trichoptera) in a central Idaho stream

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Arctopsyche grandis, a caddisfly, was studied for two years in a cold stream in central Idaho. Larvae have a one-year life cycle consisting of five instars. Three to four instars are present in most months. Growth is rapid in summer with instar I and II passing to IV and V in 30 d or less. Little or no growth occurs during winter. Maximum larval densities were 547 (1977) and 2060 m–2 (1978) of planar rock surface area. Populations fitted a negative exponential survivorship curve with similar exponents (–0.0078, –0.0103) in both years. Larval growth was generally isometric with head capsule width (403–2197 μm) and weight (0.05–16.23 mg AFDW) increasing by a factor of 1.5 between instars. Net dimensions correlated with head capsule width and nets were made by all instars and maintained throughout the year. Larvae fed preferentially on animals and diatoms avoiding vascular plant detritus. No differences were detected in diet among the instars.

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ELECTRONIC FILE - Zoology: Invertebrates

CSE-style citation: Cuffney TF, Minshall GW. 1981. Life history and bionomics of Arctopsyche grandis (Trichoptera) in a central Idaho stream. Holarctic Ecology. 4(4):252-262. Available at: doi:10.1111/j.1600-0587.1981.tb01006.x/abstract.