Estimating food availability for larval dragonflies: a cautionary note

Fecal pellets produced by larvae of Enallagma ebrium and Ischnura verticalis given ad libitum feedings of enchytraeid worms were heavier than pellets produced by larvae given ad libitum feedings of Daphnia magna. Dependence of pellet weight on food type has marked implications for indices of food limitation for larval dragonflies.