Resource Suitability Affecting Foraging Area Extension in Termites (Insecta, Isoptera)

The size of foraging areas may depend on the balance between the costs and benefits involved in the use of resources. Here, we tested the hypothesis that termites reduce their foraging area when exploring patches with more favorable resource suitability (i.e., low C/N ratio) since, rather than digging long tunnels they feed on the substrate which is closely available. As a consequence, when foraging in richer patches, termites will dig fewer and shorter tunnels, and will do so more slowly than when in patches with lower suitability of resource. To examine this, we simulated, in laboratory, an improvement in resource suitability in patches by increasing dung content in a soil-based foraging substrate. For each patch with distinct resource balance, ten repetitions were performed, using workers from different colonies of Cornitermes cumulans. Observations were made over 48 hours. As expected, in richer patches there was a decrease in the length, number and speed of the tunnel construction by termites. That is, termites excavated more intensely in patches with low suitability of essential resource and stayed longer in richer patches. Such results may help understand intriguing patterns reported elsewhere, such as the decrement of termite richness in resource-rich areas.