Competitive Interactions in Ant Assemblage in a Rocky Field Environment: Is Being Fast and Attacking the Best Strategy?

Abstract

The ant assemblage structure can be molded by mechanisms such as competition and dominance-discovery trade-off. In harsh circumstances is likely that ant species who control the food resource are the first to arrive at the baits, are more aggressive (behavioral dominance), abundant (numerical dominance) and, thus, ecologically dominants. By this characteristics combination, the dominance-discovery should not be a trade-off, but a positive relationship. Here, we examined the interactions among nine ant species in a rocky field area, in the Ibitipoca State Park, Minas Gerais, Brazil. By offering baits, we observe the dominance-discovery ability and the behaviors of attack, avoidance and coexistence of each species. We showed that Crematogaster sericea , Pheidole obscurithorax and Pheidole radoszkowskii were the best discoverers of the food resource and dominated it numerically, being this way considered ecologically dominants. Despite P. radoszkowskii being part of this relationship, this interpretation should be taken cautiously. Its dominance at the baits was assured by their high discovery ability and abundance, but the behavioral strategy exhibited was avoidance, not aggressiveness as C. sericea and P. obscurithorax . Thus, we can suppose that the discovery-dominance trade-off was broken by the linked characteristics that define the ecological dominant status of these species. Also, P. radoszkowskii demonstrates that others strategies could surpass the set of being fast and attack, and thus this is not the best strategy for all. In harsh circumstances each species has its own best strategy.