Meta-Analysis Reveals Behavioral Plasticity, Not Agonistic Behavior, Facilitates Invasion of Brown Anoles (Anolis sagrei) and Replacement of Green Anoles (Anolis carolinensis)

Abstract

In a meta-analysis, we examined the behavioral portfolio of invasive brown anoles (Anolis sagrei) and native green anoles (Anolis carolinensis) in urban and non-urban environments. We hypothesized that invasive anoles would display more agonistic and bold signals (head bobbing, dewlap extensions, and pushups) than their native-range counterparts and their native competitors. We found that in urban settings, anoles of both species signaled more with dewlap extensions than with head bobs. Brown anoles displayed significantly more in non-urban habitats and their native range compared to urban habitats and invasive ranges. The outcome of our analysis suggests that brown anoles have plastic behavioral portfolios, whereas green anoles have relatively balanced preferences for head bobbing, irrespective of the habitat in which the populations were collected. We attribute the success of the brown anole invasion to the flexible strategy in the face of higher mate competition, higher predation risks, and less resource competition in both urban and invasive ranges. Lastly, we observed publication biases. More studies were conducted with urban and invasive brown anoles and specifically in manipulative mesocosm experimental settings—transplanting populations from native field settings. We show this altered the display rates across all studied signals.