Incidence of Aggressive Territoriality between Two Ant Species: Camponotus compressus Fab. and Oecophylla smaragdina Fab. (Hymenoptera:Formicidae)

Interspecific rivalry among higher animals is not uncommon. However, it is less noticed among invertebrates, which function at micro ecological levels. One such incident was encountered by the authors in an old, neglected mango orchard on the outskirts of Bengaluru, India, between two species of ants, Camponotus compressus Fabricius and Oecophylla smaragdina Fabricius. While these two spatially co-existed and foraged in the orchard, rivalry was found on three trees which harboured arboreal O. smaragdina nests, where C. compressus (a ground nester) also began nesting at the base of the tree.

Foragers of O. smaragdina while descending the tree trunks found C. compressus at the base of the tree an intrusion (or vice versa?) and interspecific rivalry ensued for nearly seven weeks leading to mortality in both species. Overall, O. smaragdina suffered six times more loss in terms of number and biomass, but prevailed over C. compressus. The latter was forced to abandon nesting. It is important to record such interspecific processes, in insects at a micro ecological level.