Effect of social experience on behavior, stress hormone, and reproduction in native and invasive Anolis lizards.

Abstract

Invasive species damage ecosystems, economies, and human health. Understanding the traits that contribute to successful invasion improves our ability to identify and prevent future invasions before damage can occur. Anolis sagrei is a small invasive lizard displacing natural populations of its close relative, Anolis carolinensis, in the southeastern United States. I staged territorial encounters to compare the behavioral, hormonal, and reproductive consequences of social experience in the invasive and native species. Against conspecific opponents, lizards of both species were more aggressive as residents than as intruders, but only female A. sagrei responded to residency with greater plasma corticosterone. In heterospecific trials, males did not differ in behavior or plasma corticosterone based on social experience. Female A. sagrei residents and intruders differed in the relationship between reproductive variables and body size, seemingly differing in their investment in current or future reproduction. A. carolinensis females did not differ in reproductive activity based on social experience. In long-term experiences, A. sagrei females did not vary reproductive investment uniformly but prioritized different reproductive traits based on their social experience. Overall, social experience influences reproductive output in these lizard species, possibly through the mechanism of stress hormones, in ways that likely contribute to A. sagrei's success as an invasive competitor.