Six beetles with shiny green and brown shells on a leaf with bite marks.
Japanese scarab beetles (Popillia japonica) are a significant pest and strictly quarantined outside Japan. Female beetles attract mates with a mating hormone, japonilure, but males only respond to one mirror-image version of the molecule. Working with a related beetle found in southeast Asia, Anomala corpulenta, U.S. and Chinese researchers have now been able to identify the receptors that allow these insects to distinguish between mirror versions of their mating hormones. The knowledge could lead to new ways to detect, monitor and control invasive pests. (Getty Images)

Mirror Image Pheromones Help Beetles Swipe Right

There are many ways to communicate with prospective romantic partners: If you are a Japanese scarab beetle, it’s a matter of distinguishing left from right. New work from U.S. and Chinese scientists, published this week in Proceedings of the National Academy of Sciences, shows how these beetles use mirror-image pheromones to find a mate. The work could lead to better monitoring and control of significant agricultural pests.

The Japanese beetle, Popillia japonica, is a major agricultural pest that cannot be legally imported into the United States. In 1977, researchers discovered that females of P. japonica attract males with a pheromone, japonilure. Like most biological molecules, japonilure can exist in two forms that are mirror images of each other, the R-form and S-form. R-japonilure attracts males but S-japonilure repels them.

Twenty years later, Walter Leal, now professor of molecular and cellular biology at the University of California, Davis, and senior author on the new paper, discovered that a different, closely related scarab beetle, Anomala osakana, also uses japonilure as a sex pheromone, but the other way round: the S-form attracts males and the R-form repels them.

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