Behavioral differentiation among workers may reduce reproductive conflicts during colony inheritance in the termite Reticulitermes labralis

In the process of inheriting reproduction among social insects, conflicts over reproduction widely exist among potential reproductive individuals. These conflicts are expressed by the suppression of reproductive success or the competition for reproduction. However, such suppression and competition are often accompanied by high cost for individuals. Whether there may or may not be a harmonious behavioral strategy that has evolved to reduce these conflicts has received negligible attention in termites so far. Here, in the lower termite Reticulitermes labralis, we studied specific behaviors of workers before they differentiate into reproductives. Our behavioral observations show that when the queen was present, the workers which successfully replaced reproductives in the future had three different behavioral profiles compared to workers which did not develop into reproductives. That is, in queenright colony, the workers which differentiated into reproductives moved less, performed more proctodeal trophallaxis (anal feeding), and were groomed more than others. These three specific behaviors may indicate which workers have priority during the process of differentiation when queens are absent. We suggest that the weak mobility was intended to save energy, the higher number of proctodeal trophallaxis occurrences could serve as an honest signal to indicate their status, and the higher number of grooming behavior received could be a sign of dominance. Therefore, R. labralis may reduce reproductive conflicts with these specific behaviors which indicate the priority of certain workers to differentiate into replacement reproductives.