Measuring Abundance of Emerging Chironomidae (Diptera): Experiments on Trap Size and Design, Set Duration, and Transparency

Experiments at Saqvaqjuac, N.W.T. (63°39′N) showed that submerged funnel traps (0.283 m2) had equal catch rates at 10–12 °C, independent of emptying interval between 1 and 6 d. Inverted funnels in the trap jars reduced the loss of active pupae, and probably sinking dead insects. Catch rates were independent of trap size (0.071–0.283 m2) at emergence densities . Preserving-type traps which retained the catch had the same daily catch rate as regular traps when left in place up to 18 d, but none of the preservatives tried was satisfactory and decay was a problem. Catch rates for clear and opaque traps were similar.