Caterpie #010

A caterpillar is the larval stage of species belonging to the order Lepidoptera (the evolutionary clade comprising butterflies and moths). Most caterpillars eat leaves.

Osmeterium of Papilio xuthus Larva

Alpsdake (CC BY-SA 3.0)

Caterpie is displaying an osmeterium, a defensive organ found in all larvae of the family papilionidae (swallowtail butterflies). The osmeterium is extended from the front of the thorax when the caterpillar feels threatened. The organ mimics the forked tongue of a snake. The large eye spots along with the osmeterium frighten predators. Additionally, the chemicals produced by the gland reduce predation, particularly by ants (Chattopadhyay 2011; Eisner and Meinwald 1965).

Full-grown fifth instar larva of the spicebush swallowtail, Papilio troilus

Jerry F. Butler, Entomology and Nematology Department, University of Florida

Chattopadhyay, J. 2011. The structure and defensive efficacy of glandular secretion of the larval osmeterium in Graphium agamemnon agamemnon Linnaeus, 1758 (Lepidoptera: Papilionidae).

Eisner, T., and Meinwald, Y.C. 1965. The defensive secretions of a caterpillar (Papilio). Science, N.Y. 150: 1733-1735.