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 Ludwig-Maximlians-Universitaet (LMU) in Munich 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 und 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 behaviorally induced barriers to reproduction emerge is largely unknown. “When changes in