Defense Mechanisms of Arthropods. XXVII. Osmeterial Secretions of Papilionid Caterpillars (Baronia, Papilio, Eurytides)1

Abstract

The caterpillars of butterflies of the family Papilionidae possess a defensive gland, the osmeterium, consisting of an eversible 2-pronged invagination of the neck membrane. When disturbed, the larvae extrude the gland and attempt to wipe it against the offending agent. The secretion, which visibly coats the everted gland and is usually strongly odorous, has been shown in the European Papilio machaon L. to consist of 2 aliphatic acids (isobutyric acid and 2-methyl butyric acid) and to offer effective protection against ants (Eisner and Meinwald 1965). We here report on the chemistry of the osmeterial secretions of 7 North American and 1 African papilionid species.