November 7, 2005
Social learning in noncolonial insects?
Social learning and use of social information in general have been understood to be largely restricted to vertebrates. Among insects, social learning or processes akin to it have been reported only in colonial species (bees, ants, termites), suggesting that highly structured social organizations may have assisted the evolution of social learning. However, learning about predators or predation risk from others may constitute life-saving information, and not just in vertebrates or colonial insects. Theory predicts that social acquisition of such information should therefore have been evolutionarily favored in any species where members of that species can observe each other and behave differently under conditions of predation risk.
Researchers Isabelle Coolen, Olivier Dangles, and J©rÃ´me Casas, from the University of Tours, France, considered that wood crickets might be just the candidate to test for this prediction. Indeed, wood crickets typically hide under leaves when in the presence of spiders, and the high local densities at which they live may well allow for social transmission of information regarding danger.
In the new work in the journal Current Biology, the authors found that not only do crickets hide more when in the presence of others who have just experienced a dangerous environment, but they also continue to do so long after these "demonstrators" are gone. The authors showed that the long-lasting behavioral changes cannot be simply attributed to such nonsocial factors as long re-emergence times or residual odor cues, and that the most straightforward explanation for the observed behavioral changes is one involving social learning. The findings of Dr. Coolen and colleagues therefore question the common conception that social learning is restricted to large-brained animals assumed to possess superior cognitive abilities.
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