Instar and species‐specific diets in two species of Chaoborus 1

Analysis of crop contents of chaoborid larvae from Eunice Lake, British Columbia, revealed seasonal changes and instar‐specific differences in the food composition of two coexisting species —Chaoborus americanus and Chaoborus trivittatus. Diel vertical migration played an important role in determining the diet and time of feeding of C. trivittatus. Prey size, abundance, and distribution were used to interpret larval diets. Prey size determined the diet of the first three larval instars, which had difficulty handling large prey. In the fourth larval instar the diet was determined largely by the spatial availability of prey.