Dr. Robin Thomson

Caddisflies, or Trichoptera, are a diverse order of insects with over 16,000 described species. The family Hydroptilidae, known as the “microcaddisflies” due to their small body size of 1.5-5 mm, are an extremely diverse family within Trichoptera that displays a wide array of ecological, morphological, and habitat diversity. In terms of species diversity, Hydroptilidae is the largest family in the order Trichoptera, containing over 2,600 known species found in all faunal regions of the world where hundreds of new species await description. However, there is very little known about microcaddisfly evolutionary history that is supported by current phylogenetic methods. A stable phylogenetic framework based on statistically supported methods is needed to consistently define taxa and provide context for how they relate to each other and are arranged within the family overall. The microcaddisflies have shown a long history of instability and tenuous placement within Trichoptera, but tend to be grouped with several closely related families in various arrangements near the base of Trichoptera; a stable phylogeny for Hydroptilidae would also be useful for larger questions applied to the order Trichoptera in general. In addition to the ability to place and describe new biodiversity, a stable classification will make it possible to pursue numerous research directions that were previously inaccessible, such as character evolution within Hydroptilidae, evolutionary trends across Trichoptera, and the opportunity to integrate sequence data with collections-based data.

The three core scientific objectives of this proposal include:

• Phylogeny of Hydroptilidae: Construct a total-evidence (molecular + morphological) phylogeny of the family Hydroptilidae to include the first morphological assessment of homology across the family and the first molecular dataset to cover the entire family using targeted enrichment techniques.
• Targeted Revisions: As the phylogeny is constructed, it will be used to shed light on subfamilies and genera in need of taxonomic revision, updated taxonomic definitions, revisionary monographs, and new species descriptions.
• Biogeography and Divergence Estimates: The newly established and stable hydroptilid phylogeny will be used to determine biogeographic and divergence time estimates that will add to a more detailed profile of hydroptilid evolutionary history.