Evolution of Feeding and Case-Making Behavior in Trichoptera

Abstract

A phylogeny of the families of Trichoptera is reviewed to provide a basis for understanding the probable evolution of feeding tactics and case or retreat constructions by larvae. At least 48 hierarchically inclusive homologues are known, mostly from larval, pupal, and adult morphology. Their resulting phylogeny indicates that Rhyacophilidae, Hydrobiosidae, Glossosomatidae, and Hydroptilidae are more closely related to Philopotamidae, Hydropsychidae, and their allies than to Limnephilidae, Leptoceridae, and their allies. This phylogeny implies that the ancestral caddisfly larva was probably a tube-dwelling detritivore, inhabiting humus and detrital mats near the shores of lentic or lotic-depositional habitats. This ancestor evolved into a tube-case-making detritivore and scraper in the ancestor of Integripalpia and into a retreat-making collector-gatherer in the ancestor of Annulipalpia. All other larval feeding and case-making tactics evolved from these ancestral habits.