Spite and Altruism in Gulls

SPITE AND ALTRUISM IN GULLS In recent years, a controversy has developed in evolutionary biology concerning the existence of altruistic behavior in species other than Homo sapiens if true altruism is proven to exist, Darwin's (1859) theory of natural selection would be inadequate to account for all of evolution. This is because Darwin assumed that individual organisms should always act in their own self-interest, whereas altruistic behavior at least potentially reduces the fitness of an individual in order to increase the fitness of another individual. Along with the controversy over altruism, there has developed a minor, related controversy concerning spiteful behavior in animals (Hamilton 1970, 1971; Wilson 1975). Spiteful behavior is best defined by Wilson (1975 p. 117) as "behavior that gains nothing, or may even diminish the fitness of the individual performing the act, but is definitely harmful to the fitness of another (presumably a conspecific)." In practice, spite may be difficult to distinguish from purely selfish behavior, which is one of the cornerstones of Darwinian natural selection. The criterion for spite must therefore be the high risk of personal injury to the individual performing the act relative to the potential gain. I emphasize that, in describing behavior as either altruistic or spiteful, I am not implying anything about the psychological state of the individual performing the behavior. I only wish to characterize the potential effects of the act upon the fitness of the individual performing the act, and upon the fitness of the recipient of the behavior. The link between spite and altruism is the controversial implication that the individual exhibiting such behavior lowers its personal fitness. Much of the controversy concerning supposed altruistic behavior has been resolved by Hamilton (1964), who defined the concept of "inclusive fitness," and by Maynard Smith's (1964) definition of "kin selection" based on "selection of families" as suggested by Darwin (1859). These concepts, which are best exemplified by the social insects (Wilson 1971), suggest that behavior which appears altruistic may in fact be selfish in an evolutionary sense if the behavior increases the fitness of relatives more than it decreases the fitness of the performer. Some organisms, however, appear to show altruistic behavior under conditions where it would seem spurious to invoke kin selection. To account for such behavior within the bounds of Darwinian natural selection, Trivers (1971) suggested the concept of "reciprocal" altruism, where the individual acts of altruism are not …