Two Sex-Specific Volatile Compounds Have Sex-Specific Repulsion Effects on Adult Locusts Locusta migratoria manilensis (Meyen) (Orthoptera: Acrididae)

Abstract

Gregarious locusts use volatile semiochemicals released from their bodies and feces to regulate their biological characteristics, and many of these compounds are sex-specific. The locust Locusta migratoria manilensis (Meyen) (Orthoptera: Acrididae) is a frequent plague species in China, but very little is known of its olfactory behavioral ecology. In our previous study, one malespecific compound (2-heptanone) was identified from body volatiles of gregarious adult L. m. manilensis. In the present study, six compounds were identified from fecal volatiles of gregarious adult L. m. manilensis using a gas chromatograph coupled to a mass spectrometer: 3-Methyl-1-butanol, cyclo hexanol, 2,5-dimethylpyrazine, 6-methyl-5-hepten-2-one and 2,6,6-trimethyl-2-cyclohexene-1,4-dione were present in the fecal volatiles of both sexes, and 2,2,6-trimethylcyclohexanone only in that of females. Olfactometric bioassays indicated that the male-specific 2-heptanone repelled the adult males, but had no effect on females. On the other hand, female-specific 2,2,6-trimethylcyclohexanone was found to repel the adult females, but had no effect on males. The two sex-specific compounds may help to improve reproductive efficiency of the locusts.