Meeting Abstract
Nest structures of termites arise from the aggregate labor of many individuals. Grassé proposed that the labor of termites is coordinated by stigmergy, an indirect mode of communication whereby the work product of a builder acts to guide subsequent workers. In his proposed framework, construction is driven by a positive feedback interaction between termites, mediated by “cement pheromone” used to stimulate additional construction at scent-labeled sites by other termites. Based on Grassé’s initial work, and bolstered by a small number of empirical studies, many have produced virtual simulation models of termite construction or excavation that rely on agents imparting a label to work sites that decays in some fashion and orients the labor of subsequent agents at threshold concentrations. Recent work on subterranean termites has demonstrated that such scent labels are not necessary for the organization of cadres of termites excavating tunnels. Instead the excavation process is governed solely by the tactile interactions of termite excavators and patterns of traffic flow. The behavior of termites in queues of excavators awaiting access to the extending tips of tunnels is responsible for scaling tunnel width to traffic flow and results in the emergence of bifurcation. We present a scheme of tunnel excavation that does not invoke cement pheromone to organize labor. Additionally we present data from mound building Macrotermes spp. that questions the pheromone nature of scent imparted to soil deposited by termite during construction. Our work calls into question the key organizing factor of current dogma on insect construction.
