Female sexual response to male rectal volatile constituents in the fruit fly, Bactrocera carambolae (Diptera: Tephritidae)

The production of a major component, 6-oxo-1-nonanol and a minor compound, N-3-methylbutyl acetamide in the male rectal gland of Bactrocera carambolae, a fruit pest of economic importance, increased concomitant with age, and their peak production corresponded with sexual maturity. During courtship period, these endogenous components were released unchanged into the air as visible smoke by a group of 100-150 males in a glass chamber. Male emissions elicited upwind flight via zigzag anemotaxis, and attracted more conspecific virgin females than males in wind tunnel assays. When these components were assayed individually, both 6-oxo-1-nonanol and N-3-methylbutyl acetamide elicited significant female responses toward the source chemicals, although the response was less than that for live males. The results suggested that these volatile components are involved in the intraspecific communication by playing a role as sex pheromones during courtship of 5. carambolae.