Agonistic behavior between individual worker termites from three cuticular hydrocarbon phenotypes of Reticulitermes (Isoptera: Rhinotermitidae) from Northern California

Abstract

Bioassays examining aggression in termites have typically been performed by pairing groups of workers from different colonies. We examined whether similar results would be observed using bioassays with individual workers. We report the results of pairings of individual workers of Reticulitermes spp. of three different hydrocarbon phenotypes (CA-A, CA-B, and CA-C). Resulting agonistic behavior between individuals can be used to infer relatedness of workers from different foraging groups because identification of species of Reticulitermes is often difficult. Pairings consisted of two termites from the same colony or from different colonies with the same or different phenotypes. We recorded avoidance behavior and immediate aggression during 5-min observations and mortality at 24 h. Intercolonial/intraphenotype pairings paralleled group bioassays with low levels of immediate aggression; however, individual pairings had lower levels of mortality at 24 h. Bioassays using individual Reticulitermes spp. workers in interphenotype, pairings yielded results comparable with previously reported group bioassays and could be used in lieu of group bioassays. However, if immediate aggression is lacking, it would be advisable to use group bioassays or increase the number of replications to differentiate intracolonial and intercolonial pairings. Survival rates were the same for all phenotypes when paired with either of the other two phenotypes. There were, however, significant differences in the number of avoidance responses; pairings with CA-C had the highest number of avoidance responses followed by pairings with CA-B and CA-A. There were significant differences in immediate aggression; CA-C was the most aggressive, followed by CA-B and CA-A. Different levels of aggression among phenotypes provide additional evidence that these phenotypes represent distinct taxa or species.