Proceedings of the Royal Society B: Biological Sciences
Restricted accessResearch articles

Accommodating natural and sexual selection in butterfly wing pattern evolution

Jeffrey C. Oliver

Jeffrey C. Oliver

Department of Ecology and Evolutionary Biology, Yale University165 Prospect Street, New Haven, CT 06520-8106, USA

[email protected]

Google Scholar

Find this author on PubMed

,
Kendra A. Robertson

Kendra A. Robertson

Department of Biological Sciences, State University of New York at BuffaloBuffalo, NY 14260, USA

Google Scholar

Find this author on PubMed

and
Antónia Monteiro

Antónia Monteiro

Department of Ecology and Evolutionary Biology, Yale University165 Prospect Street, New Haven, CT 06520-8106, USA

Department of Biological Sciences, State University of New York at BuffaloBuffalo, NY 14260, USA

Google Scholar

Find this author on PubMed

    Visual patterns in animals may serve different functions, such as attracting mates and deceiving predators. If a signal is used for multiple functions, the opportunity arises for conflict among the different functions, preventing optimization for any one visual signal. Here we investigate the hypothesis that spatial separation of different visual signal functions has occurred in Bicyclus butterflies. Using phylogenetic reconstructions of character evolution and comparisons of evolutionary rates, we found dorsal surface characters to evolve at higher rates than ventral characters. Dorsal characters also displayed sex-based differences in evolutionary rates more often than did ventral characters. Thus, dorsal characters corresponded to our predictions of mate signalling while ventral characters appear to play an important role in predator avoidance. Forewing characters also fit a model of mate signalling, and displayed higher rates of evolution than hindwing characters. Our results, as well as the behavioural and developmental data from previous studies of Bicyclus species, support the hypothesis that spatial separation of visual signal functions has occurred in Bicyclus butterflies. This study is the first to demonstrate, in a phylogenetic framework, that spatial separation of signals used for mate signalling and those used for predator avoidance is a viable strategy to accommodate multiple signal functions. This signalling strategy has important ramifications on the developmental evolution of wing pattern elements and diversification of butterfly species.

    References