Intraspecific competition for a nest and its implication for the fitness of relocating ant colonies

Intraspecific competition is a fundamental ecological process. Studies in ants have explored this mainly in the context of foraging. There is a notable gap in our understanding of competition dynamics during goal-oriented task of colony relocation even though this task impacts the survival and fitness of colonies. Here, we instigated a competition between equal (n = 17) and unequal (n = 14) sized Diacamma indicum colonies for a new nest and contrasted our findings with two sets of controls—colonies that relocated without facing any competition and colonies that did not relocate. In majority of the trials, one colony successfully occupied the new nest and colony size was a factor in determining this success. In addition, colonies with more explorers and lower latency to start recruitment had a significantly higher chance of occupying the new nest. In 23% of the trials, both colonies merged, following cross colony tandem recruitment and one of the gamergates was killed. The level of aggression displayed by the competing colonies was comparable, but the wining colonies had a lower percentage of colony involved in aggression. Higher levels of aggression were noted in the area close to at the old and new nest site. Further, there was exchange of pupae between competing colonies and larger colonies showed 2.86 times higher pupae theft. Losing colonies experienced significantly higher mortality as compared to controls. Winning colonies experienced higher mortality as compared to non relocating controls. This study showcases how intraspecific competition during colony relocation shapes colony composition, fitness and population dynamics in an ant community.