The mechanisms and rules of coordinated building in social insects

Summary

This chapter presents an overview of the mechanisms, usually intertwined, used by social insects to build their often elaborate nests: templates, stigmer-gy, self-organization and self-assembly. A few models based on these mechanisms are also discussed, but they are to a large extent speculative because experimental evidence is scarce. Our conclusion is that it is not necessary to invoke individual complexity to explain nest complexity. Recent work suggests that a social insect colony is a decentralized system comprised of cooperative, autonomous units that are distributed in the environment, exhibit simple probabilistic stimulus-response behavior and have access to local information. The complexity of a nest is likely to result from the unfolding of a morphogenetic process during which past construction provides both constraints and new stimuli. This form of indirect communication between insects through the environment is an important aspect of collective coordination, and has been coined’ stigmergy’ by Grassé. We show that stigmergy has to be supplemented with a mechanism that makes use of these interactions to coordinate and regulate collective building. We suggest that at least two such mechanisms play a role in social insects: self-organization and self-assembly. When they are combined with templates, they became the building blocks of a powerful construction game.