"What is interesting is that, while the pheromone attracts males, it repels virgin females," Hoover said. "This may be a mechanism to help females avoid competition for a mate."
In addition, the researchers learned that sexually mature females continue to produce the trail pheromone after mating, a practice they think benefits both sexes. According to the scientists, by continuing to produce the pheromone after mating, females can lure the same males back to mate again or they can lure other males to them.
"Females benefit from multiple matings or from a prolonged time spent copulating with one male because these behaviors increase the likelihood that her eggs will be fertile," said Melody Keena, research entomologist, U.S. Department of Agriculture, Forest Service, Northern Research Station.
In contrast, a male benefit from ensuring that only his sperm is used to fertilize the female's eggs, thereby passing only his genes on to the next generation.
"We now have more information about the series of complex behaviors, as well as chemical and visual cues and signals that facilitate mate location and help the male find the female again on a huge tree in order to guard her from other males," Hoover said.
All four trail pheromone components have been synthesized and behavior activities have been evaluated in the laboratory bioassays, according to Aijun Zhang, research chemist, U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Invasive Insect Biocontrol and Behavior Laboratory. The synthetic trail pheromone may be useful in managing the invasive beetles in the field. Zhang isolated, identified and synthesized the pheromone.
"It is possible that the synthetic version of pheromone could be used in combination with an insect pathogenic fungus that is being studied at Cornell University by Ann Hajek," Hoover said.
"This fungus can be sprayed on a tree, and when beetles
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