Peptide dampens moth's sex appeal.

When corn earworms mate, the males leave their partners with more than just sperm -- they also transfer a substance that makes the females less eager to find other mates. This substances, called soluble pheromonostatic factor, is a basic peptide containing 57 amino acids, says Wanda M. Bodnar, a graduate student in chemistry at the University of Virginia in Charlottesville. She and her colleagues reported this result at the annual meeting of the American Society for Mass Spectometry, held this month in Washington, D.C.

Like many months, this agricultural pest courts via volatile chemicals called pheromones. The female releases pheromones to attract male. Tim G. Kingan at the U.S. Department of Agriculture research center in Beltsville, Md., had isolated this factor and demonstrated that once the male passes it to the female, she makes much less pheromone and becomes less receptive to mating. Using a sophisticated analytical procedure involving mass spectrometry and high-performance liquid chromatography, Bodnar's group then determined the sequence of amino acids in this peptide. The peptide may prove useful in controlling corn earworms; it may "trick them into thinking they have already been fertilized," Bodnar says.