Researchers pinpoint chemical signal that speeds mati...( ordani salamanders caught in the field...)

To test the activity of PRF, they removed the mental glands of male salamanders and placed the males in boxes with sexually receptive females. "The males acted as though their glands were still present and would still attempt to deliver courtship pheromones," explains Rollmann. But because the glands were removed, Rollmann could control which chemicals were delivered to the females.

For each pair, Rollmann delivered either purified PRF or saline to the females. In pairs where the female was given PRF, courtship time was reduced by approximately 15 percent compared to pairs where the female received saline. "This reduction is a conservative estimate of female response in that the females in the study had been pre-selected for a high propensity to court in laboratory conditions," says Rollmann.

Pheromones such as PRF that can encourage and speed up the mating process play an important role in survival. "By shortening the amount of time spent in tail-straddling walk, the chances of courtship being interrupted by predators, or other males, is reduced," Rollmann explains.

Rollmann and colleagues also pinpointed the gene that codes for PRF. "By studying the gene, we can get a better idea of how this courtship pheromone evolved and begin to study its mechanism of action," she says.

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Contact: Sharon Parmet
sparmet@mcis.bsd.uchicago.edu
773-702-6241
University of Chicago Medical Center
17-Sep-1999