Meeting Abstract
Invasive species often displace native species that they closely resemble or compete extensively with. The mechanisms behind invaders’ competitive success can vary widely, ranging from aggressive dominance over resources (interference competition) to superior resource utilization (resource competition). In this study, we looked for evidence of interference competition between an invasive lizard species, the brown anole (Anolis sagrei), and a closely related competitor that it displaces in the wild, the green anole (A. carolinensis). We housed captive populations of green anoles in large outdoor structures in Oak Ridge, Tennessee, and recorded their display behaviors and habitat use for 10 days. We then introduced brown anoles and recorded the green anoles’ behaviors for another 10 days, looking for differences in pre- and post-invasion behaviors. We also recorded behavioral interactions between the two species. To serve as a density control, we repeated the experiment in a second enclosure using green anoles to “invade” the first populations. We found no evidence that brown anoles behaviorally dominate green anoles. Although brown anole males regularly displayed at green anoles, green anoles were generally uninterested in brown anoles and were more likely to interact with newcomers of their own species. Green anoles also did not change their display behaviors or activity levels in the presence of brown anoles. This study provides insights into how a native species responds to a closely related invasive competitor and indicates that social relationships between species do not necessarily reflect ecological relationships.
