Meeting Abstract

86.1  Thursday, Jan. 7  Adaptive divergence in green anole lizards due to species invasions HSIEH, S.T.*; SMITHERS, C.; University of Florida, Gainesville; Temple University, Philadelphia, PA; University of Florida, Gainesville sthsieh@post.harvard.edu

Phenotypic plasticity is cited as a mechanism that can facilitate adaptive evolution, by enabling an immediate response to sudden environmental changes, effectively “buying time” for an organism to genetically adapt to the new conditions. Previous studies have shown that when green (Anolis carolinensis) and brown anoles (Anolis sagrei) were raised on narrow and broad surfaces, individuals raised on narrow surfaces reached adulthood with shorter limbs than did those raised on broad surfaces (Kolbe and Losos, 2005; Losos et al., 2000). In Florida, brown anole lizards were introduced to the southern tip in the mid-1930s, and have since invaded northward throughout the state, reaching the northernmost border in the mid-1990s. The brown anole invasion in Florida has appeared to decimate the native populations of green anoles while forcing habitat displacement and a vertical habitat shift (Campbell, 2000) on to narrower surfaces. We hypothesized that as a result of increased competitive pressures and subsequent vertical habitat shift associated with the brown anole invasion, post-invasion populations of green anoles would have shorter limbs than pre-invasion populations. To test this hypothesis, we obtained green anoles from museum collections representing populations from Florida, Georgia, and South Carolina. For each individual, we measured fore- and hindlimb lengths, and head length, width, and height. Results show significantly shorter hindlimbs and smaller heads among post-invasion populations, reflecting the habitat shift and possible associated differences in prey type. Work is currently underway to determine if the detected morphological differences are due to plasticity or adaptive evolution.