Male endogenous pheromonal component of Bactrocera carambolae (Diptera: Tephritidae) deterred gecko predation

Summary.

Geckos consumed immature Bactrocera carambolae males readily, but their consumption was reduced significantly when offered sexually mature males. They showed a similar aversion for sexually mature males previously fed with methyl eugenol. When male flies at different ages were offered to starved geckos, geckos’ consumption showed an age-related anti-feeding effect, which was concomitant with the production trend of 6-oxo-1-nonanol, a major endogenous component synthesized in the male rectal gland. The production of 6-oxo-1-nonanol was also age-related and corresponded with sexual maturity as reported previously. Topical application of the authentic chemical of 6-oxo-1-nonanol onto the thorax of female fruit flies, at the amount normally detected in the rectal gland of a sexually mature male, had the same deterrent effect against geckos.