Thesis Research

My research addresses a common evolutionary phenomenon: island dwarfism. Many animals evolve smaller body sizes following colonization of islands. There are several abiotic (thermal environment, precipitation) and biotic (prey, competitors, predators) reasons for this trend, but these have not been widely tested by evolutionary ecologists. I am studying why insular rattlesnakes are small in relation to their closest relatives on the mainland. I will use a combination of approaches to test whether these differences have an underlying genetic basis or if they are the result of resource differences (food or the thermal environment) for southern Pacific rattlesnakes (Crotalus helleri). First, I will statistically document the size differences of insular and mainland populations of this species from southern California by measuring several size components of preserved snakes held in natural history museums. Next, I will record the growth rates of neonates from island and mainland populations in a "common garden" in which animals are reared under identical conditions. This will determine whether genetics or environmental conditions play a greater role in growth and, ultimately, adult body sizes. Then, I will gather data on the availability of thermal and food resources from insular and mainland populations. Finally, I may include a field component in which I monitor the activity (daily and seasonal) and feeding rates of radio-telemetered rattlesnakes from island and mainland populations. This final component may also include control and experimental animals, the latter of which will be provided supplemental meals. My study has broad implications for either adaptive evolution of body size (if size differences are genetically based) or phenotypic plasticity (if differences are environmentally driven).

Awards and Honors

• Student Research Grant, $1250, Southern California Academy of Sciences (2007)
  Why are rattlesnakes on islands smaller than on the mainland?.
• Bellinger Student Research Award, $700, Department of Biology, California State University, Northridge (2007)
  Why are rattlesnakes smaller on islands than on the mainland?