Nestmate recognition is a necessary capacity for the occurrence of discrimination between nestmate and non-nestmate individuals. In one-piece nesting termites, which nest and forage in a single piece of wood, nestmate recognition is poorly studied mainly because the probability of encountering exogenous individuals is low in comparison with separate-piece nesting termites. Previous work described that production of soldiers of Neotermes chilensis, a one-piece nesting termite, increased when the risk of invasion of their colony increased, for example when neighboring colonies were present in the same nesting substrate and members of different colonies met when digging galleries. If soldiers are to fulfill their defensive role under these circumstances, they should show nestmate recognition ability; moreover, based on work on other social insects, such nestmate recognition should be based on cuticular compounds (CC). Bioassays were performed in which a soldier of N. chilensis was confronted with a nestmate or non-nestmate primary reproductive, pseudergate or another soldier, and in which a soldier was confronted with untreated and with CC-deprived dead primary reproductives. The results showed that soldiers were indeed more aggressive toward non-nestmates than nestmates for all castes, and that this discrimination was mediated mainly by qualitative (simple matching coefficient) and quantitative (Renkonen index) differences in CC

Background: In one-piece nesting termites, which nest and forage in a single piece of wood, soldier production increases during the swarming period, i.e. when the risk of invasion of their substrate and hence of their colony by dealates in search of a nesting substrate increases. In Neotermes chilensis, a one-piece nesting termite endemic to Chile, we hypothesized: i) that during swarming soldiers would defend their colony by showing higher aggressiveness toward non-nestmate than toward nestmate dealates, ii) that aggressiveness would negatively correlate with genetic relatedness of interacting soldier/dealate pairs and iii) that nestmate recognition would be based on differences in cues provided by cuticular compounds (CC) between nestmates and non-nestmate dealates. Methods: The first hypothesis was tested using bioassays in which a soldier was confronted with a nestmate or a non-nestmate dealate; the second hypothesis by using microsatellites to assess genetic relatedness of the interacting pairs; and the third hypothesis using bioassays in which a soldier was confronted with a nestmate or a non-nestmate dead dealate with or without its CC and with dead dealates with interchanged CC between nestmate and non-nestmate. Results: Soldiers were more aggressive toward non-nestmate than nestmate dealates, aggressiveness was inversely correlated with genetic relatedness of the interacting pair, and CC accounted for the differences in aggressiveness towards nestmate and non-nestmate dealates. Conclusions: During swarming, soldiers of N. chilensis protect their nest against invasion by non-nestmate conspecific dealates; discrimination is based on CC and aggressiveness correlates inversely with genetic relatedness of the interacting soldier/dealate pairs.