|Vander meer, Robert - Bob|
Submitted to: Proceedings of the Royal Society of London: Biological Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/26/2002
Publication Date: 7/17/2003
Citation: BOULAY, R., KATZAV-GOVANSKY, T., VANDER MEER, R.K., HEFETZ, A. Colony insularity through queen control on worker social motivation in ants. Proceedings of the Royal Society of London: Biological Sciences. 2003. v. 270. p. 971-977. Interpretive Summary: A key element in the success of ants is that a colony's queen(s) is usually shielded from outside intrusions of pathogens and parasites by large numbers of sterile workers. Nestmate recognition (recognition of other members of your colony) maintains this colony insularity, thus workers from each colony of a given species may be behave aggressively toward workers from another colony and compete for territory and resources. As important as this process is, our understanding of the contributions of workers and queen(s) is rudimentary. Scientists at the Center for Medical, Agricultural and Veterinary Entomology and the Department of Zoology, Tel Aviv University, Israel, through a U.S.- Israel Binational Science Foundation grant have determined that the workers from the carpenter ant, Camponotus fellah, are the source of nestmate recognition cues and also blend and distribute the cues throughout the colony. In contrast, the queen contributes little to the cues, but influences nestmate recognition by reducing worker tolerance of non-nestmates. Understanding nestmate recognition in ants may lead to better ways to get pathogens and parasites past the formidable defences of pest ants, such as the fire ant, Solenopsis invicta.
Technical Abstract: We investigated the relative contribution of the queen and workers to colony nestmate recognition cues and on colony territoriality in the ant Camponotus fellah. Workers were either individually isolated, preventing contact with both queen and workers (Colony Deprived, CD), kept in queenless groups, allowing only worker/worker interactions (Queen Deprived, QD) or in queenright groups (QR). Two weeks post separation QD and QR workers were amicable toward each other but both rejected their CD nestmates. This suggests that the queen does not measurably influence the colony recognition cues. In contrast, aggression between QD and QR workers from the same original colony was apparent only after six months of separation. This clearly demonstrates the power of the "Gestalt" and indicates that the queen is not a dominant contributor to the nestmate recognition cues in this species. Aggression between nestmates was correlated with a greater hydrocarbon (HC) profile divergence for CD than for QD and QR workers supporting the importance of worker-worker interactions in maintaining the colony "Gestalt" odour. While the queen does not significantly influence nestmate recognition cues, she does influence colony insularity since within three days QD (queenless for six months) workers from different colony origins merged to form a single queenless colony. In contrast the corresponding queenright colonies maintained their territoriality and did not merge. The originally divergent cuticular and PPG HC profiles became congruent following the merger. Therefore, while workers supply and blend the recognition signal, the queen affects worker-worker interaction by reducing social motivation and tolerance of alien conspecifics.