Gregarious mature male-specific volatiles and the semivolatile cuticular hydrocarbon fraction of the South American locust, Schistocerca cancellata

Abstract

The South American locust, Schistocerca cancellata (Serville 1838), is considered to be the most serious agricultural pest in Argentina and neighboring countries. The species is famous for the strong and pleasant aromatic scent of mature males in the gregarious phase. We identified this fragrance as a mixture of two main aromatic compounds, benzyl alcohol, and 2-phenylethanol. The male-specific volatiles are emitted almost exclusively from the abdomen. The release of the male volatiles is linked to sexual maturity and is influenced by the intensity of sexual competition between males. Consequently, a function of the volatiles as a gregarious mature male-emitted pheromone in the context of reproduction is obvious. No female-specific volatiles were found. Some compounds of the semivolatile fraction of the cuticular hydrocarbon (CHC) profile were also detected in the headspace of both sexes. This fraction of the CHCs of S. cancellata consists almost entirely of unbranched C23 to C31 alkanes. The profiles vary slightly between the sexes and differ from the reference profile of the prominent and well-studied species S. gregaria. Thus, semivolatile components of the CHCs may also play an important role in the short-range mate recognition system of the species.