Where Are You Now, My Love? (6/27/2008)

Walter Leal, professor of entomology and chemical ecologist at the University of California, Davis, receives a handful of Japanese beetles (Popillia japonica). Through his research into the beetles' sex pheromones, Leal and his team have isolated, identified, cloned and expressed a pheromone-degrading enzyme that could be manipulated to keep males from finding and mating with females. This discovery could lead to important applications in controlling Japanese beetles, invasive pests that have threatened U.S. agriculture since 1916. - Credit: Kathy Keatley Garvey, UC Davis Department of Entomology

Discovery related to Japanese beetles' sex pheromones has implications for agricultural pest control

Having a good nose is essential to a Japanese beetle's survival. The beetle's sense of smell helps it avoid enemies and zero in on a mate. Meanwhile, the potential mate is programmed to release sex pheromones in exactly the right proportions. Like cheap perfume, there is such a thing as too much: Excessive pheromones can get the attention of a passing fly, leading her to the beetle. The fly can then lay her eggs on the beetle's back, setting up emerging fly larvae for their first meal (fresh Japanese beetle).

If all of this isn't challenging enough, the male beetles have to track females while they're both flying. This requires a mechanism within the males that loses the pheromone scent from a moment before and picks up the latest scent as the females move through the air.

This mechanism is well understood by Walter Leal, a chemical ecologist at the University of California, Davis. With funding from the National Science Foundation, Leal has isolated, identified, cloned and expressed a pheromone-degrading enzyme that allows receptors in the beetle's nose to lose the pheromone scent from the female's earlier locations as she moves to new places.

Isolating this enzyme offers the potential to eliminate entirely the beetle's reception of the pheromone scent, making them unable to find females, mate and reproduce. This potential could be useful to agricultural pest control, since the Japanese beetle is an invasive species responsible for millions in damages to crops each year.

Note: This story has been adapted from a news release issued by the NSF

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