Selfish Creatures, Huddled Together for Warmth

Abstract

THOUGH THE major players in the Modern Synthesis tended increasingly toward an organism-only view, the problem of the interaction between individual animals in groups, colonies, populations and species did not go away. One of the pioneering investigators of animal interaction was the Chicago-based ecologist Warder Clyde Allee (Fig. 6.1). Allee’s laboratory studied the positive benefits of interaction (or simply of co-existence) between individuals (see Courchamp et al. 2008, for an overview of Allee’s work and its influence). His studies, primarily on fish, emphasized the role of cooperation in promoting animal survival under conditions of stress or scarcity. In works such as The Social Life of Animals (1938), where he compiled the results of studies from many other laboratories in addition to his own, Allee demonstrated again and again that, while competition clearly occurs in nature, cooperation provides an important balancing tendency. He emphasized that, while under many conditions overcrowding could be deleterious to a population, under other circumstances undercrowding could be equally detrimental. This phenomenon is now known as the Allee effect, and appears regularly in nonlinear models of population dynamics, as well as in experimental studies ranging from the mating behavior of wild dogs to quorum sensing in the formation of bacterial biofilms.