Does Distance Among Colonies and Resource Availability Explain the Intercolonial Aggressiveness in Nasutitermes aff. coxipoensis?

Abstract

Aggressive behaviour can ensure animal access to local resources. To reduce constant costs in the defence of territories, species could save energy with conflicts avoiding aggression with neighbour or in situations with abundance of resources. In the present study, we analysed the effect of distance among colonies and resource availability on the aggression level and responses to chemical cues of Nasutitermes aff. coxipoensis (Holmgren) (Termitidae: Nasutitermitinae). Manipulation of resource offer was conducted in the field, where nests with different distances were kept without addition of baits (control), with addition of three or 16 sugarcane baits/nest. After 3months, aggressiveness, linear and Y-shaped trail-following bioassays were carried out with all pairwise combinations of colonies in each treatment. Our results showed that aggressive index of N. aff. coxipoensis was affected by the resource availability. However, individuals from colonies with 0 and 3 baits/nest showed a higher number of fighting with neighbours than those from non-neighbours colonies. Termite workers from colonies without baits (control) followed shorter distance in the linear trails compared to those from colonies with addition of baits. In all treatments, there was no preference of workers in relation to the choice of chemical cues from own or other colonies. The response of intercolonial aggressiveness in N. aff. coxipoensis seems to be resource-dependent. These results may contribute to the comprehension of the use of space by N. aff. coxipoensis and could be useful to explain patterns of termite co-occurrence at different spatial scales, from local (inside the nest-e.g. cohabitation of nests by inquilines) to regional (e.g. around the nest).