It’s Not Easy Being Green: Behavior, Morphology, and Population Structure in Urban and Natural Populations of Green Anole (Anolis carolinensis) Lizards

Simon P Lailvaux

doi:10.3389/fevo.2020.570810

Abstract

Selection on behaviour, signalling, and morphology can be strongly affected by variation in habitat type. Consequently, populations inhabiting different environments can exhibit divergent phenotypes as a result of either habitat-specific selection or plasticity. Urban habitats in particular represent different challenges for organisms adapted for rural environments, including disparate complements of predators and competitors, resource availability, and habitat complexity. In this paper, I review work aimed at understanding the different selective challenges experienced by rural and urban populations of green anole lizards, primarily those in southeastern Louisiana. I also describe a long-term mark-recapture experiment on an urban population of green anoles in New Orleans, and consider how sex ratios and population density changes over time. Collectively, this work shows that urban and rural populations of green anoles diverge markedly in behaviour and morphology driven both by differences in habitat and the presence of competitors in the urban environment; however, it also shows that the effects of urbanization on the ecology and evolution of green anoles are understudied.

Highlights

A key principle in evolutionary biology is that environmental differences among populations can drive divergent selection on morphology, behavior, and physiology
Following Irschick et al (2005b) I considered adult males to be greater than 45 mm snout-vent length (SVL), and adult females to be greater than 40 mm SVL
Urban populations show distinct differences in morphology, performance, and behavior in a number of animal taxa. This brief review demonstrates that A. carolinensis is among those species whose behavior and ecology are altered by urban environments

Summary

Introduction

A key principle in evolutionary biology is that environmental differences among populations can drive divergent selection on morphology, behavior, and physiology. The nature of the divergence is determined by the specific environmental challenges in conjunction with the evolutionary history of the species or population in question, we can discern broad patterns of repeated evolutionary change in response to similar selection pressures (Langerhans and DeWitt, 2004; Losos, 2011; Moore et al, 2016; Auer et al, 2018). Urban environments comprise a specific habitat milieu that is characterized by distinct structural habitat and environmental variables such as light or thermal regime, amongst others. These urban environments frequently differ markedly from the natural habitats and environments of the organisms inhabiting urban areas.

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