Social interactions in the central nest of Coptotermes formosanus juvenile colonies

Abstract

Juvenile colonies of Coptotermes formosanus Shiraki were investigated to determine the social interactions among all individuals near the central nest of a colony. The behavioral repertoire of whole colonies of subterranean termites has yet to be identified because of their cryptic nests. Colonies were placed in planar arenas, and their behavioral repertoire and activities were recorded with video cameras. All castes and larval instars were determined and behavioral interactions were monitored and described, including feeding behaviors, grooming, nest maintenance, and inactivity. When two termites interacted, it was also determined which one was the donor or the recipient of the act. An ethogram was constructed by calculating relative frequency of each behavior for first instar larvae, second instar larvae, first instar workers, second instar workers or older, queen, king, soldiers and presoldiers. Larval instars, primary reproductives and soldiers were mostly passive during interactions. Workers performed most of the tasks; however, there was a difference of task divisions among worker instars. Young workers (W1) performed most of the grooming of individuals in the central nest, while older workers (W2+) provided nest maintenance and sanitation, by collecting fecal matter from most nest mates. In addition, older workers were mostly in charge of caring for the primary reproductives and the maintenance of the royal chamber. This study identified instar-specific activities and provides a first insight into caste and age polyethism in C. formosanus.