Discovery dominance tradeoff: the case of Pheidole subarmata and Solenopsis geminata (Hymenoptera: Formicidae) in neotropical pastures.

Interspecific competition has been shown to play a role in the structure of ant communities. However, the role of foraging behavior and the type of competition that results from this behavior has been less investigated. Here we present results from baiting experiments at various scales to determine the degree of exploitative and interference competition between two Neotropical ants (Hymenoptera: Formicidae) in pastures in the Atlantic coast of Nicaragua. Results suggest that the coexistence of Solenopsis geminata (Fabricius) and Pheidole subarmata (Mayrs) in Neotropical pastures is the result of a discovery/dominance tradeoff between these two species. Although S. geminata is a good interference competitor and can defend large resources, P. subarmata is a good exploitative competitor and arrives at resources faster than S. geminata. In an environment with mixed resources (large and small), these two species can co-exist. We discuss the implication of this for the invasion potential of S. geminata.