Novel chemistry of abdominal defensive glands of nymphalid butterfly Agraulis vanillae.

Abdominal defensive glands of both sexes of the Gulf fritillary butterfly, Agraulis vanillae (Linnaeus) (Nymphalidae:Heliconiinae) emit a pronounced odor when disturbed. We have identified 6-methyl-5-hepten-2-one; oleic, palmitic, and stearic esters of the corresponding alcohol 6-methyl-5-hepten-2-ol; hexadecyl acetate; 1,16-hexadecanediol diacetate; and 1,15-hexade-canediol diacetate in the glandular exudate. Since we have determined that free-flying birds or birds in a butterfly conservatory discriminate against A. vanillae as prey, we suggest that the constituents in the glands may play a defensive role against potential avian predators.