The Higher Level Phylogeny of the Trichoptera (Insecta)

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9632879 KJER This study involves a molecular phylogenetic analysis of higher level (suborder and family) relationships among members of the caddisflies (Insecta: Trichoptera) based on sequence data from both the mitochondrial and nuclear genomes. Knowledge of the phylogeny and evolution of this group of aquatic insects is of interest to freshwater ecologists, behavioral biologists, biodiversity advocates (Trichoptera larvae are classic water quality indicators), and historical biogeographers. In particular, the evolution of case and retreat making behavior of the immatures has been the center of spirited debate. Three competing hypotheses have emerged for the evolution of these traits that differ in their presumed character state homologies and transformation series (TS). The molecular phylogeny provided by this investigation will be used to test the alternate TS, using character mapping; preliminary results suggest that putative homologies of some behaviors will need to be reassessed. This research will also address methodological issues such as weighting schemes, Transition-transversion bias, and how to incorporate secondary structure concerns in rRNA analysis; these methodological concerns are of broad interest to the systematic community. This award will help support training of graduate students in modern methods of molecular systematic analysis and enhance our knowledge of this important element of insect biodiversity. Caddisflies are important elements of fresh water ecosystems and their species composition in streams has been used to assess and monitor water quality.