EXPLORATIONS IN INSECT SOCIALITY: TOWARDS A UNIFYING APPROACH

An important trend in the study of insect societies has taken place in the last 30 years. Traditional theories of social organization such as adaptive demography and worker castes have been revised in the light of new evidence of the dynamic nature of regulatory processes underlying social behaviour. However, this new trend is still markedly reductionist in its methods. This paper advocates a unifying approach to the study of insect sociality, illustrated by an agent-based computational model allowing detailed investigations of the dynamics of insect social behaviour. The model incorporates key components of social organization and their underlying mechanisms, both at the individual and colony levels. The model was applied to field studies of behavioural plasticity in red harvester ants, in order to evaluate its performance when applied to a concrete problem in insect sociobiology. Simulation experiments reproduced several aspects of harvester ant social organization and produced insights into the dynamics of collective responses to changing ecological conditions. The results suggest that temporal patterns of colony resource allocation may be more complex than currently believed. We found a non-linear relationship between ecological stress and the colony's response strategy, revealing a significant event in the temporal dynamics of the system behaviour: the collapse of the relative priorities of communal tasks. We present a testable hypothesis about the hierarchy of task priorities in harvester ants, as well as suggestions for an experimental procedure for testing the hypothesis. The paper concludes with a discussion of the prospects and pitfalls of computational approaches to the study of insect societies.