Age polyethism of workers in relation to egg clusters in juvenile colonies of Coptotermes formosanus Shiraki

A termite colony is composed of workers of different ages, but an age polyethism has yet to be reported in lower termites. We hypothesized the presence of age polyethism in workers of juvenile colonies of Coptotermes formosanus Shiraki (4yrs-old) and that individuals display a different behavior as a function of the distance from the central part of the nest, represented by the egg cluster. Two larval instars and two worker instars were determined by the head width of individuals of juvenile colonies placed in planar arenas. Grooming behavior and wood consumption of first and second instar workers were monitored at different distances from the egg cluster with a video camera. We observed that grooming behavior was mostly performed by the first instar workers close to the egg cluster, while second instar workers consumed wood throughout the nest most of the time. In addition, we observed that second instar workers performed larvae transportation near the egg cluster and groomed arena walls near the royal pair, while significantly smaller number of first instar workers were involved in these two tasks. Our results showed that age polyethism is present in C. formosanus workers and that the distance from the egg clusters affected the task performed by first and second instar workers.