Altruism, Spite, and Greenbeards

Abstract

Spite and Altruism Many social animal species can exhibit altruism—the loss of their own individual fitness to help others. One of the most extreme examples is that of the social insects (bees and ants) where, in a colony of related individuals, only a few reproduce. The nonreproductive individuals contribute to the success of the young of these individuals thereby increasing their collective fitness. Spite occurs when an individual damages its own fitness to harm another's. This negative form of altruism can arise if the victim is less related to the perpetrator than an average member of the population. West and Gardner (p. 1341 ) review the current literature on the origins and maintenance of altruism and spite and the associated phenomenon of greenbeards. Greenbeards use a visible inherited character to signal relatedness and spur altruism. Greenbeard genes provide a mechanism to link the genes that encode cooperative behavior with those that cause cooperators to associate. These traits maybe an ornament or a type of behavior, and they may result in altruistic or spiteful behavior.