Submitted to: Behavioral Ecology and Sociobiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2009
Publication Date: 10/7/2009
Citation: Liebig, J., Eliyahu, D., Brent, C.S. 2009. Reproductive-specific cuticular hydrocarbon profiles in a termite: Evidence of convergent evolution in social insect signaling mechanisms.. Behavioral Ecology and Sociobiology. 63:1799-1807.
Interpretive Summary: Colonial insects like ants, bees and termites are composed of reproductive and non-reproductive individuals. This division is crucial for ensuring colony stability, and requires a communication system in which fertile individuals let their nestmates know of their status. The best way to produce a reliable signal is through physiological markers tightly associated with reproductive status. Wax-like chemical components on the surface of insects, originally used as a barrier against water loss, have been linked to individual fertility in some insects. In a dampwood termite, we identified four chemicals that are unique to reproductive individuals of both sexes. The chemicals may provide signals that inhibit the reproductive development of immature nestmates. The similarity of this termite signaling system with that found in unrelated species of ants and bees suggests widespread adaptation of this anti-desiccation mechanism into a complex communication system crucial to colony function. Understanding the communication system will facilitate the development of targeted methods for controlling termite populations.
Technical Abstract: The maintenance of a reproductive division of labor in social insects is achieved through the reliable communication of individual fertility status. A central question is whether there exists a general mechanism underlying this communication system across species. The best way to produce a reliable signal is through physiological markers tightly associated with reproductive status. Cuticular hydrocarbons exhibit this link to individual fertility in several species of ants, bees and wasps and we present the first evidence for such a signaling system in a non-Hymenopteran eusocial species. In the termite, Zootermopsis nevadensis, we identified four polyunsaturated alkanes which only occur in significant amounts on individuals that are actively producing gametes. In contrast to Hymenopteran social insects, both sexes express the reproductive peaks. The reproductive-specific hydrocarbons may act as primer pheromones, inhibiting the reproductive development of immature conspecifics. The similarity of this termite signaling system with that found in the phylogenetically distant Hymenoptera suggests widespread convergent evolution in social insects involving the co-option of a mechanism normally used to prevent desiccation.