The intestinal microbes inducing the agonistic behavior of inter-colonial individuals in Coptotermes formosanus (Isoptera: Rhinotermitidae)

The inducing mechanism of the agonistic behavior of the Formosan subterranean termite Coptotermes formosanus Shiraki is complex, and there is little information available thus far. The role of intestinal microbes in nestmate recognition of C. formosanus was investigated in this study through treating workers from the same colony or different colonies with three antibiotics: penicillin, streptomycin and tetracycline. The results showed that the intestinal microbes were involved in the induction of the agonistic behavior of intercolonial individuals in C. formosanus. Agonistic intensity of workers between two colonies that are originally incompatible was not influenced significantly when only one colony of termites was treated with all three antibiotics. After the same colonies of termites were treated with different antibiotics, obvious agonistic behaviors between workers treated with different antibiotics were observed. The agonistic behaviors between workers from two colonies were strengthened or weakened significantly when two colonies of termites were all treated with different antibiotics. We concluded that certain species of intestinal microbes are involved in the induction of the agonistic behavior of inter-colonial individuals in C. formosanus.