Morphological plasticity in a caddisfly that co-occurs in lakes and streams

摘要: Lake and stream fauna are frequently studied, yet surprisingly little is known about ecological and evolutionary dynamics of species that inhabit both lentic and lotic habitats. There are few examples of species co-occurring in different flow types, which raises questions about how co-occurrence may influence ability to adapt to changing climatic conditions. One such co-occurring species is the aquatic insect Limnephilus externus Hagen, 1861 (Trichoptera:Limnephilidae), a species known to be widely distributed in lakes of the Nearctic and Palearctic regions. Here, we test whether lake–stream populations of the caddisfly L. externus are evolutionarily or ecologically distinct. We examined larval body and case morphology, interspecies phoretic associations, and the mitochondrial DNA cytochrome c oxidase I gene among lake and stream populations of L. externus. We also explored potential morphological differences …