Meeting Abstract

44.5  Saturday, Jan. 5  Survival at what cost?: Consequences of a native lizard’s adaptations to invasive fire ants THAWLEY, C.J.*; ROBBINS, T.R.; LANGKILDE, T.; Pennsylvania State University; Pennsylvania State University; Pennsylvania State University

Anthropogenic environmental change, including introductions of non-native species, imposes novel selective pressures on native species. A population’s ability to persist under these threats can depend on its capacity to adapt accordingly. However, responses to an altered fitness landscape may not be optimal across all environments or life stages. We conducted a field transplant experiment using Eastern Fence Lizards, (Sceloporus undulatus) to investigate how a population’s history of coexistence with predatory red imported fire ants (Solenopsis invicta) affects fitness (survival). Fence lizards in fire ant invaded sites have altered behavior and morphology, which are assumed to increase survival under this novel threat. We show that both adult and juvenile lizards from populations historically invaded by fire ants have higher survival in the presence of fire ants than do lizards from uninvaded populations. Adult lizards from invaded populations, however, appear maladapted when fire ants are absent, having lower survival than naïve lizards under these conditions. Juvenile lizards show an advantage associated with exposure to fire ants but do not experience the same costs as adults. These ontogenetic differences in the consequences of adaptation to fire ants may derive from the specific outcomes associated with each adaptation. Adults from fire ant invaded sites exhibit behaviors that promote escape from fire ants but expose them to mortality via native predators; whereas juveniles demonstrate innate avoidance of eating fire ants, which protects them from envenomation. Studying the downstream effects of pressures imposed by invasive species can provide insights into the longer-term consequences of environmental change on community interactions and the persistence of biodiversity.