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Conspicuous male coloration impairs survival against avian predators in Aegean wall lizards, Podarcis erhardii.

Marshall KL, Philpot KE, Stevens M - Ecol Evol (2015)

Bottom Line: Within-species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology University of Cambridge Cambridge CB2 3EJ UK.

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.

No MeSH data available.


Related in: MedlinePlus

Survival of male versus female models. Showing cumulative survival rate of clay models of Aegean wall lizards (Podarcis erhardii) against avian predator attacks on Skopelos (A) and on Syros (B) over five consecutive days. The model treatments were designed to resemble male and female coloration (from both island populations), and a brown control that did not replicate P. erhardii coloration (N = 300; males = 120, females = 120, control = 60).
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ece31650-fig-0006: Survival of male versus female models. Showing cumulative survival rate of clay models of Aegean wall lizards (Podarcis erhardii) against avian predator attacks on Skopelos (A) and on Syros (B) over five consecutive days. The model treatments were designed to resemble male and female coloration (from both island populations), and a brown control that did not replicate P. erhardii coloration (N = 300; males = 120, females = 120, control = 60).

Mentions: Planned comparisons showed that attack frequency by birds was significantly different among male, female, and control models on Skopelos (W2 = 9.732, P = 0.008) (Fig. 6A). We found that birds attacked male‐colored models significantly more frequently than female‐colored models (W1 = 8.025, P = 0.005; exp(B) = 0.269) (Fig. 6A). However, the island color type of the models (i.e., whether they were local (Skopelos) or non‐local (Syros)) did not significantly influence attack frequency by birds (W2 = 1.380, P = 0.502; Fig. 7). In all analyses, the significance of the results was unchanged when missing models were included (i.e., treated as attacked).


Conspicuous male coloration impairs survival against avian predators in Aegean wall lizards, Podarcis erhardii.

Marshall KL, Philpot KE, Stevens M - Ecol Evol (2015)

Survival of male versus female models. Showing cumulative survival rate of clay models of Aegean wall lizards (Podarcis erhardii) against avian predator attacks on Skopelos (A) and on Syros (B) over five consecutive days. The model treatments were designed to resemble male and female coloration (from both island populations), and a brown control that did not replicate P. erhardii coloration (N = 300; males = 120, females = 120, control = 60).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588654&req=5

ece31650-fig-0006: Survival of male versus female models. Showing cumulative survival rate of clay models of Aegean wall lizards (Podarcis erhardii) against avian predator attacks on Skopelos (A) and on Syros (B) over five consecutive days. The model treatments were designed to resemble male and female coloration (from both island populations), and a brown control that did not replicate P. erhardii coloration (N = 300; males = 120, females = 120, control = 60).
Mentions: Planned comparisons showed that attack frequency by birds was significantly different among male, female, and control models on Skopelos (W2 = 9.732, P = 0.008) (Fig. 6A). We found that birds attacked male‐colored models significantly more frequently than female‐colored models (W1 = 8.025, P = 0.005; exp(B) = 0.269) (Fig. 6A). However, the island color type of the models (i.e., whether they were local (Skopelos) or non‐local (Syros)) did not significantly influence attack frequency by birds (W2 = 1.380, P = 0.502; Fig. 7). In all analyses, the significance of the results was unchanged when missing models were included (i.e., treated as attacked).

Bottom Line: Within-species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology University of Cambridge Cambridge CB2 3EJ UK.

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.

No MeSH data available.


Related in: MedlinePlus