title: Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots.
abstract: Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits (Parus major) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, with natural-looking eyespots, and manipulated spots with the same contrast but reduced resemblance to an eye, as well as images of predators (owls) with and without eyes. We found that mimetic eyespots were as effective as true eyes of owls and more efficient in eliciting an aversive response than modified, less mimetic but equally contrasting eyespots. We conclude that the eye-mimicry hypothesis explains our results better than the conspicuousness hypothesis and is thus likely to be an important mechanism behind the evolution of butterfly eyespots.
authors: University of Jyväskylä, Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, Jyväskylä, Finland sebastiano.debona@gmail.com.
authors: Sebastiano
authors: S
authors: De Bona
authors: University of Jyväskylä, Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, Jyväskylä, Finland.
authors: Janne K
authors: JK
authors: Valkonen
authors: University of Jyväskylä, Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, Jyväskylä, Finland CNRS UMR 7618, Institute of Ecology and Environmental Sciences of Paris (iEES), Université Pierre et Marie Curie, Paris, France.
authors: Andrés
authors: A
authors: López-Sepulcre
authors: University of Jyväskylä, Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, Jyväskylä, Finland.
authors: Johanna
authors: J
authors: Mappes
mesh_terms: D000818:Animals; D000067558:Biological Mimicry; D002080:Butterflies / Q000502:physiology*; D005123:Eye; D010858:Pigmentation; D020308:Songbirds / Q000502:physiology*; D014796:Visual Perception; D014921:Wings, Animal / Q000502:physiology*
keywords: IRTree GLMMS; animal coloration; deception; eyespots; mimicry; predator–prey interactions