HOW SHOULD WE TEST FOR THE ROLE OF BEHAVIOR IN POPULATION-DYNAMICS

The behaviour of an individual affects the probability that it will fi nd food or a mate, and whether it will avoid becoming food itself. Bec ause the birth and death of individuals are the constituents of the bi rth and death rates of populations, it seems likely that population dy namics is affected by variation in the behaviour of individuals. While intuitively appealing, there are few data to support this contention. I suggest that this lack of support stems from the failure to make us e of manipulative experiments to test the hypothesis. Manipulative exp eriments are not the only approach to testing these hypotheses, but th is powerful tool has not been used as effectively as it might. The beh aviour of an animal can be manipulated with information-carrying chemi cals in its environment, and pharmacologically. Variation in behaviour among individuals that is genetically based can also provide experime ntal material to test hypotheses about the role of behaviour in popula tion dynamics. Manipulative experiments have the advantages of increas ed statistical power, and the elimination of unmeasured covariates. Th ey have the disadvantage that they can introduce artifacts into the st udy system. It seems unlikely, however, that different kinds of manipu lations would produce the same kinds of artifacts.