Meeting Abstract
During biological invasions, non-native invaders often experience environments that differ substantially from those found in their native range; these novel conditions can impose strong directional selection and lead to rapid phenotypic divergence between native and invasive populations. The brown anole (Anolis sagrei) is a small lizard native to Cuba and the Bahamas that has invaded the southeastern United States over the past century. Native and invasive populations experience different climatic variables with more northern invasive populations experiencing lower mean annual temperatures and shorter breeding season lengths than more southern native populations. Because invasion success hinges on the ability of a population to survive and expand, we hypothesized that invasive populations whose reproduction is limited by a shorter breeding season would experience strong selective pressure to decrease egg incubation time and the spacing between egg lays. We collected brown anoles from 4 native island populations in the Bahamas and from 4 populations in the southeastern United States ranging from southern Florida to Georgia. Eggs produced by females from each population were incubated at 28°. We found that eggs from invasive populations hatched significantly faster than those from native populations, and that females from invasive populations had shorter intervals between egg lays than did females from native populations. Together, these results support that the shortened breeding season experienced in the invasive range has led to the rapid divergence of life history traits in Anolis sagrei.
