Volatile components of male rectal glands of the melon fly, Dacus cucurbitae Coquillett (Diptera: Tephritidae)

Ethyl 4-hydroxybenzoate was identified as a major aromatic volatile in the rectal glands of Dacus cucurbitae males, together with two minor analogs, methyl and propyl 4-hydroxybenzoate. The quantity of ethyl ester was very low at early adult stage but increased with sexual maturation up to a level of 10 mu g/male. 1,3-Nonandiol was identified as one of the aliphatic components. It was also demonstrated that D. cucurbitae males which were artificially fed with cue-lure selectively accumulated its hydrolyzed derivative, 4-(4-hydroxyphenyl)-2-butanone, in the rectal glands.