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Evolutionary stability of vigilance coordination among social foragers

Rodriguez-Girones, M.A. and Vasquez, R. (2002) Evolutionary stability of vigilance coordination among social foragers. Proceedings of the Royal Society B-Biological Sciences, 269, 1803-1810. ISSN 0962-8452.

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Coordination can greatly improve the efficiency of anti-predatory vigilance scans by increasing predator detection for a constant proportion of time spent vigilant. However, it has been rarely found in nature and most studies have detected or assumed independent scanning by group members. In this study, we analysed the functional consequences of the coordinated alternation of vigilance scanning by group foragers. We introduce coordination by assuming that interscan intervals (ISIs) follow a modified gamma distribution. Depending on the parameters of the distribution, successive scans can be evenly spaced (coordinated scanning) or may present a high overlap (uncoordinated scanning). Comparing evolutionarily stable strategies for animals that do not coordinate their scanning with animals that do coordinate their anti-predator behaviour shows that coordination has a marked effect on survival probability. Moreover, the coordinating strategy is quite robust against mutants that scan independently with exponential distributions of ISIs. However, coordination breaks down when animals can continuously adjust their level of coordination by deciding the proportion of time they spend monitoring the behaviour of other group members. In this case, coordination is only evolutionarily stable if it can be very easily achieved.

Item Type:Article
ID Code:11213
Deposited On:24 Nov 2011 01:00
Last Modified:24 Apr 2012 16:35

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