Behavioral rules for soil excavation by colony founders and workers in termites

Social insects produce complex nest structures as a result of the repetition of simple behaviors by many individuals. Individual actions are often consistent across different socio-environmental conditions, which enables colonies to build a variety of structures with minimal change in behavior. In this study, we show that the individual building behavior of termites can be a species-specific trait shared even between distinct morphological castes. Subterranean termites engage in soil excavation in two different contexts in their life history: foraging for resources by workers and initial nest excavation by colony foundation pairs. Our comparison of tunneling behaviors by colony founders of three different species revealed distinct transporting mechanisms; Heterotermes aureus (Snyder) (Isoptera: Rhinotermitidae) and Gnathamitermes perplexus (Banks) (Isoptera: Termitidae) carry sand particles using only their mandibles, while Paraneotermes simplicicornis (Banks) (Isoptera: Kalotermitidae) use their legs to kick sand particles backward. The observed behaviors are consistent with those of workers in each species, despite a substantial dimorphism of body size, especially in G. perplexus. Furthermore, the behavioral difference is associated with distinct tunnel development and task allocation patterns among species. Our study suggests that the nest building behavior of termites varies little with context or function within a species but can change among species, emphasizing the fruitfulness of comparative studies in future research.