In a recently published study in the Journal of Evolutionary Biology, co-authored by SWDTP student Michael Hawkes, scientists from the University of Exeter have shown that a trait subject to mate choice in the fruit fly Drosophila simulans varies in expression and attractiveness across different environments. These results highlight how predicting the outcome of sexual selection can be complicated by environmental variation, and that that genetic covariance of traits across environments may constrain the independent evolution of traits subject to mate choice between environments.
Sexual selection constrained by environmental differences
Sexual selection explains why male house finches are blushed bright red and the tails of male long-tailed widow birds are so cumbersome. In both species females use these traits to choose mates and drive the evolution of males with brighter plumage and longer tails. However, the evolution of these traits is also influenced by natural selection – bright red plumage relies on extracting red pigment from food, a long tail is expensive to produce, and both make it more difficult to evade predators. Understanding the relationship between the natural and sexual selection acting on traits subject to mate choice is essential to understanding how these traits evolve, particularly when the expression and attractiveness of particular genotypes can vary between environments.
Citation: Ingleby F. C., Hosken D. J., Flowers K., Hawkes M. F., Lane S. M., Rapkin J., House C. M., Sharma M. D., and Hunt J. Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans. Journal of Evolutionary Biology, 27(4), 700-713. doi:10.1111/jeb.12338