N. Perrin et L. Lehmann, Is sociality driven by the costs of dispersal or the benefits of philopatry? A role for kin-discrimination mechanisms, AM NATURAL, 158(5), 2001, pp. 471-483
The role of ecological constraints in promoting sociality is currently much
debated. Using a direct-fitness approach, we show this role to depend on t
he kin-discrimination mechanisms underlying social interactions. Altruism c
annot evolve under spatially based discrimination, unless ecological constr
aints prevent complete dispersal. Increasing constraints enhances both the
proportion of philopatric (and thereby altruistic) individuals and the leve
l of altruistic investments conceded in pairwise interactions. Familiarity-
based discrimination, by contrast, allows philopatry and altruism to evolve
at significant levels even in the absence of ecological constraints. Incre
asing constraints further enhances the proportion of philopatric (and there
by altruistic) individuals but not the level of altruism conceded. Ecologic
al constraints are thus more likely to affect social evolution in species i
n which restricted cognitive abilities, large group size, and/or limited pe
riod of associative learning force investments to be made on the basis of s
patial cues.