It is a general rule among social insects that colony members specialize on different tasks required for the growth, defense, and reproduction of the colony. Most previous studies of division of labor among workers have limited analysis to the level of the "caste," the group of workers performing a given role for a prolonged period of time. However, some recent evidence suggests that behavioral differences among individual members of a caste may play an integral role in how the colony organizes work. Dr. Jeanne's research will take the analysis of the organization of work in social-insect colonies down to the level of the individual. The overall goal is to understand how the colony's response to a contingency, which at the global level appears to be deterministic (certain), is put together from the responses of individual workers, which appear to be idiosyncratic and probabilistic. Dr. Jeanne will analyze nest-construction behavior of a species of tropical wasp on which he has already done detailed preliminary work. He has two objectives within his overall goal. The first objective is to determine the characteristics and behavioral correlates of individual variability in nest construction. Experiments will be conducted on individually marked workers, working within the social context, to determine if their levels of activity are related to age and to different individual thresholds of response to the stimuli that release nest-construction activities. The second objective is to experimentally test for mechanisms hypothesized to regulate nest-construction behavior. The end result will be an understanding of the nest-construction system in terms of responses to stimuli, feedback pathways, and modes of communication among workers engaged in the activity. What we know so far about the coordination of complex activities of social insects suggests a parallel with what Sydney Brenner and his associates are finding out about development in simple organisms, namely that much of the "grammar of assembly" lies in the interaction among the component parts of the system. Specifying this grammar for a social insect is the ultimate goal of this research.
