In their efforts to identify the genetic basis for differences in mate choice that keep two co-existing species of butterfly separate, evolutionary biologists at LMU have identified five candidate genes that are associated with divergence in visual mating preferences.
The evolution of a new species often involves a change in mating preference. This happens, for instance, when members of different populations of a given species cease to mate with each other because they no longer find potential partners sufficiently attractive. Two closely related species of tropical butterflies, Heliconius melpomene and Heliconius cydno, provide an interesting example of this phenomenon. The two species are often seen flying together, and crosses between them can result in fertile hybrid offspring. – Nevertheless, individuals of the two species hardly ever mate with each other in the wild. How such behaviourally induced barriers to reproduction emerge is largely unknown. “When changes in behaviour are genetically hard-wired, as mate choice seems to be in our butterflies, they must involve alterations in sensation, that is, the stimuli they can detect, or changes in how these stimuli are processed,” says LMU evolutionary biologist Dr. Richard Merrill. Together with members of his group, and collaborators at the Smithsonian Tropical Research Institute in Panama and at the University of Cambridge, he has now identified five genes that are linked to the different mating preferences of H. melpomene and H. cydno. As the authors report in the open access journal Nature Communications, these genes are likely to change how visual stimuli are processed during courtship, without altering how the butterflies perceive the world in other contexts. MORE
Header image: Heliconius melpomene. Credit: R. Merrill.