The Role of Lipids, Fungi, and Temperature in the Nutrition of a Shredder Caddisfly, Clistoronia magnifica

Abstract

Diets of conditioned alder (Alnus rubra) leaves, alder plus fatty acid methyl esters, alder plus aquatic hyphomycete fungi, fungi alone, and alder plus wheat were fed to larvae of the shredder caddisfly, Clistoronia magnifica (Trichoptera: Limnephilidae), at two temperatures. Larvae did not complete development on the alder or alder plus fatty acids diets. Larvae fed diets of alder plus fungi and fungi alone completed development to adults but failed to reproduce. Alder plus wheat fed larvae completed development and reproduced. Large triglyceride stores synthesized from wheat starch allowed reproduction in alder plus wheat fed animals. Nitrogen did not appear to limit reproduction because protein content of animals did not differ between diets. Temperature did not affect survival or growth rate. However, at the higher, non-optimal temperature, triglyceride levels were reduced during the pupal stage of animals fed alder plus wheat. It is suggested that food quality should be defined in terms of reproductive capacity and that temperature-food quality interactions are mediated through lipid metabolism in this insect.