Role of the osmeterial gland in swallowtail larvae (Papilionidae) in defense against an avian predator

Third and fifth instar of Papilio polyxenes with and without a functional osmeterium were presented to Coturnix coturnix (Japanese quail). Virtually all larvae were rejected, irrespective of osmeterial function. Larvae of P. cresphontes with functional osmeteria were also universally rejected; larvae of P. glaucus were readily consumed. In view of the fact that osmeterial secretions in these three species are similar in composition, they are unlikely to play a major role in determining palatability of these species to this avian predator. -from Authors