University Park, PA (February 13, 2014) – Female Asian longhorned beetles lure males to their locations by laying down sex-specific pheromone trails on tree surfaces, according to an international team of researchers. The finding could lead to the development of a tool to manage this invasive pest that affects about 25 tree species in the United States.
“Tens of thousands of hardwood trees, mostly maples, have been cut down and destroyed in New York, Ohio and Massachusetts because of the Asian longhorned beetle,” said Kelli Hoover, professor of entomology, Penn State. “We discovered a pheromone produced by females of this species that could be used to manage the pest.”
According to the research, published in the Journal of Chemical Ecology, researchers isolated and identified four chemicals from the trails of virgin and mated female Asian longhorned beetles — Anoplophora glabripennis — that were not found in the trails of males.
They found that the pheromone trails contained two major components — 2-methyldocosane and (Z)-9-tricosene — and two minor components — (Z)-9-pentacosene and (Z)-7-pentacosene. The team also found that every trail sample contained all four of these chemical components, although the ratios and amounts changed depending on whether the female was virgin or mated and depending on the female’s age.
“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 walk on it, they pick up the fungus, which infects and kills them. By also applying the pheromone that female beetles use to attract males, we can trick the male beetles into going to the deadly fungicide rather than to a fertile female.”
The team plans to further investigate the pheromone by attempting to identify where on the body the female produces it, how the pheromone is detected by the male, how long the pheromone remains detectable on the tree and if there are other behaviors that might be mediated by these chemicals.
The U.S. Department of Agriculture, Agricultural Research Service, Forest Service; the Alphawood Foundation; and the Horticultural Research Institute supported this research.
Other authors on the paper include Maya Nehme of Lebanese University; Peter Meng, graduate student in entomology, Penn State; and Shifa Wang of Nanjing Forestry University.
Source: “Asian longhorned beetles pheromone could be used to manage pest,” Penn State News