Chemical ecology of nestmate recognition in social wasps.

Insect communication is a central topic in insect sciences. Much information is known about how insects respond to simple chemical signals but the question remains how insects use the complex information in multicomponent chemical signals. For example, in social insects, recognition signals often have > 50 epicuticular hydrocarbons which communicate colony affiliation. Colonies have exclusive memberships and colony residents promptly detect and reject non-members, i.e., non-nestmates. However, intruders, e.g., parasites, overcome chemical nestmate recognition and exploit colony resources. The chemical tricks that parasites use to circumvent host detection vary. Cleptoparasites have not enough recognition cues to allow prompt detection by their hosts; obligate social parasites use a mixture of lack of recognition cues and chemical mimicry; finally, facultative social parasites change colony odours by overmarking andmay be particularly rich in epicuticular hydrocarbons. Each chemical strategy is deeplylinked to the level of specialization and the quality of the host-parasite relationship.