The study, to be published in the Feb. 14 issue of Nature, unveils for the first time a sexual "arms race" in a group of insects - the water strider. Professors Locke Rowe of the University of Toronto's zoology department and Goran Arnqvist of the University of Uppsala in Sweden offer a new and quite different look at the fundamental conflicts of interest between the sexes.
"Males and females of most animal species look and behave very differently," says Rowe. "Males are often provided with various distinct traits like the bright colours of a peacock's feathers, for example. Females, however, aren't easily impressed. These elaborate traits in males have traditionally been explained as evolutionary consequences of females searching for good fathers for their offspring."
The key to their research lies in the fact that males and females play very different roles in reproduction. What is best for one sex is rarely best for the other, leading to a range of sexual conflicts, says Rowe. "Males of most animal species benefit from mating often with as many partners as possible while females, who are already mated, lose from mating too much. Males, therefore, seek to 'convince' females to mate while females evolve resistance measures to foil the male's mating attempts."
The traits which males use in these conflicts vary, ranging from elaborate ornaments to grasping structures that make it difficult for females to escape. The result of such sexual conflict is, in theory, an "arms race" between the sexes whereby male persistence is matched by female resistance. Such arms rac
Contact: Janet Wong
University of Toronto