When Professor Joel Levine's team genetically tweaked fruit flies so that they didn't produce certain pheromones, they triggered a sexual tsunami in their University of Toronto Mississauga laboratory. In fact, they produced bugs so irresistible that normal male fruit flies attempted to mate with pheromone-free males and even females from a different species-generally a no-no in the fruit fly dating scene. The study, published in the Oct. 15 issue of Nature, points to a link between sex, species recognition and a specific chemical mechanism, and is part of Levine's larger research into the genetic basis of social behaviour. "This is important not only from the point of view of understanding social dynamics, but it's also fundamental biology, because these pheromones provide recognition cues that facilitate reproductive behaviour," says Levine, an assistant professor of biology. "Lacking these chemical signals (pheromones) eliminated barriers to mating. It turned out that males of other species were attracted to females who didn't have these signals, so that seemed to eliminate the species barrier."
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