What are the evolutionary and ecological drivers of aposematism and color mimicry?
Mimicry is often celebrated as one of the most straightforward examples of natural selection yet a majority of known mimetic complexes are found only in the tropics. I recently described and am currently studying a large mimicry complex in North American velvet ants. With collaborators at the University of Nevada, Reno (UNR) and Utah State University (USU), I am investigating how different ecological factors influence the evolution of imperfect mimicry in velvet ants and hover flies. While female velvet ants are well defended and participate in a Müllerian mimicry complex, the males are harmless yet are often aposematically colored. Interestingly the males do not always match the color of their conspecific female, which indicates that males may participate in various Batesian mimicry complexes. Furthermore, various other arthropods (e.g., jumping spiders) mimic velvet ants, forming Batesian mimicry complexes.
Using next-generation sequencing and genome-level datasets in population genetics and phylogenetics.
Next-generation sequencing techniques have recently become more accessible and affordable, which has led to the collection of large, genome-level datasets. I am currently collaborating with researchers from various institutions around the country to gather genome-level datasets in order to address population genetics and evolutionary biology questions in a taxonomically difficult group like velvet ants. I am also in comparing my past phylogenetic and phylogeographic work using traditional sequencing to new hypotheses generated from the larger datasets.
What historic events drove diversification in North America’s desert biota?
While several research groups have investigated historical biogeographic patterns in arid-adapted vertebrate species, little work is being done on the diverse arthropod fauna that exists in the Nearctic deserts. Through molecular-based phylogenetic and phylogeographic analyses, coupled with molecular dating techniques and ecological niche modeling, I have investigated the history of diversification in several arthropod groups. While at Utah State University, much of my work focused on velvet ants, but I have also collaborated with various researchers to examine pylogeographic patterns in bees, antlions, tarantulas, and butterflies. This work has added to our understanding of the factors driving diversification in the deserts in multiple ways. My work has led to the discovery of cryptic species, identified several historic events that influenced diversification, including Neogene mountain building and Pleistocene climatic change, and led to the recognition of several apparent Pleistocene refugia, which are important areas for conserving biodiversity. I will continue to investigate the history of diversification in other arthropod groups, particularly bees, which are more diverse in the Nearctic deserts than they are in the tropics and have received a great deal of attention from federal agencies, making bee studies especially fundable.
Using molecular phylogenetics to test species and subspecies boundaries in morphologically difficult groups.
Preserving biodiversity has long been a goal of biologists. Before effective management strategies can be developed, however, a clear understanding of species boundaries is needed. In some groups, it is difficult, if not impossible, to determine taxonomic status based on morphology alone. I use molecular phylogenetics to understand species and subspecies boundaries so informed management decisions can be made. I then use ecological niche models to determine if what ecological factors are important for determining species ranges. With colleagues at the University of Nevada, Reno, I have investigated genetic diversity in a group of Nevada butterflies that are considered “at risk” by the state’s Natural Heritage Program Office, finding little support for subspecies designations. Also, in collaboration with researchers at Utah State University and the American Entomological Institute, I examined diversity in tarantulas endemic to California’s coastal mountains, where we found that the four currently recognized species represented a single species, and that two additional unrecognized species lived in the foothills of the Sierra Nevada Mountains. My work has also uncovered several unrecognized velvet ant species, leading to taxonomic revisions in multiple groups. Furthermore, I have discovered and described a nocturnal wasp that is only known from the Algodones Sand Dunes in southern California. I will continue to use molecular techniques, including next-generation sequencing, to investigate patterns and boundaries of biodiversity.
What factors influence the diversity and distributions of arid-adapted animals?
Understanding the patterns of biodiversity is an essential step in preserving healthy and sustainable ecosystems. Because of their importance to natural ecosystems, bees and wasps can be considered keystone components of healthy environments. Pinpointing areas of high bee and wasp diversity or high endemism can aid conservation decisions aimed at preserving the future of biodiversity. I have investigated the diversity of native bees on a sand dune complex in the eastern Great Basin Desert, where I found surprisingly high beta-diversity in bee communities on neighboring dunes. Also, my work identified a diverse bee fauna in the mountains of north central Washington and a rich velvet ant fauna in the deserts of California. Because a growing body of evidence suggests native pollinator diversity is declining worldwide, it is important not only to document diversity, but also to identify the spatial and temporal patterns of diversity in natural and agricultural landscapes. Future research projects will include the effects of roads on pollinator diversity, the efficacy of sand dune management strategies on restoring biodiversity, and the comparison of diversity and activity patterns of velvet ants and bees. Also, I will investigate the ecological factors that contribute to the maintenance of diverse bee communities in both agricultural and natural landscapes.