DISSERTATION RESEARCH: Speciation, niche divergence, and character displacement at multiple scales in Lasiopogon robber flies (Diptera: Asilidae)

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How are distinct niches in communities filled when interactions among species may constrain potential overlap? Robber flies in the genus Lasiopogon are a widespread group of insect predators that hunt in many environments, such as dunes, beaches, trails, streamsides, and sagebrush landscapes. Specializations such as perching habits or seasonal emergence times provide a way for species with overlapping ranges to reduce competition. The goal of this project is to compare diversification patterns and similarities in geographic range, niche, and morphology throughout the 60 species of North American Lasiopogon to uncover not just when and where a given species split, but how regional communities (i.e., who it evolved with) influenced this diversification. Understanding the processes of adaptation at regional and local scales will help show how environmental cues and interactions among species maintain and promote biodiversity, providing lessons about potential responses of species to shifting environments. This research will promote taxonomic expertise and training in a diverse but understudied group of insects (robber flies). Furthermore, since many Lasiopogon species have highly specialized habitat requirements, this work will provide data for studying community changes precipitated by urban spread, manmade irrigation, and climate change. An undergraduate student will be trained in Asilidae taxonomic and biodiversity research, and distributional and ecological information
from this study will be shared on general and taxon-specific websites. Species niches are a distillation of their interactions with other members of the community and their phylogenetic history. This research will estimate evolutionary relationships among North American Lasiopogon from sequencing multiple loci. Microniche characteristics and ecological niche models will be estimated from museum specimens and samples by the PIs. Phylogenetic comparative methods will then be used to examine the effects of ecological specialization at different spatial scales and morphological character displacement on diversification and community assembly. This study design will reveal whether ecological and morphological differences accumulated during or after species divergence, and which axes of variation (coarse- or fine-scaled ecology, morphology, phenology) have been more influential in fueling character displacement and competitive specialization.