Abstract
Animal coloration is strikingly diverse in nature. Within-species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival. Here, we tested whether color variation between two island populations of Aegean wall lizards (Podarcis erhardii) is due to sexual dimorphism and differential survival of individuals varying in appearance. On both islands, we measured attack rates by wild avian predators on clay models matching the coloration of real male and female P. erhardii from each island population, modeled to avian predator vision. Avian predator attack rates differed among model treatments, although only on one island. Male-colored models, which were more conspicuous against their experimental backgrounds to avian predators, were accordingly detected and attacked more frequently by birds than less conspicuous female-colored models. This suggests that female coloration has evolved primarily under selection for camouflage, whereas sexually competing males exhibit costly conspicuous coloration. Unexpectedly, there was no difference in avian attack frequency between local and non-local model types. This may have arisen if the models did not resemble lizard coloration with sufficient precision, or if real lizards behaviorally choose backgrounds that improve camouflage. Overall, these results show that sexually dimorphic coloration can affect the risk of predator attacks, indicating that color variation within a species can be caused by interactions between natural and sexual selection. However, more work is needed to determine how these findings depend on the island environment that each population inhabits.
Highlights
Intraspecific color divergence has attracted much scientific interest as a model system to study evolution
Ecology and Evolution published by John Wiley & Sons Ltd
On one of the two study islands, models exhibiting sexually dimorphic coloration of Aegean wall lizards (Podarcis erhardii) were attacked at different rates by avian predators
Summary
Intraspecific color divergence has attracted much scientific interest as a model system to study evolution. Across a range of animals, divergence arises through sexual dichromatism, whereby selection typically favors conspicuous signals in males for mating and sexual competition, while camouflage against predators is generally more important in females (e.g., Andersson 1994; LeBas and Marshall 2000; Alonso-Alvarez et al 2004; Stuart-Fox et al 2004; Cummings et al 2008; Gomez et al 2009; Bajer et al 2010, 2011; Higham et al 2010; Perez i de Lanuza et al 2013; Marshall and Stevens 2014). Increasing evidence shows that certain adaptations can offset the potential costs of conspicuous coloration, such as signal partitioning and private channels of communication to reduce detection by eavesdroppers
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have