Salim Ali School of Ecology and Environmental Sciences, Pondicherry University, Pondicherry 605 014, INDIA.
Very little is known about the ground foraging ant communities of the Indian subcontinent. Ground foraging ant community in a primary tropical evergreen forest and in an adjacent semievergreen logged forest in the Coorg region of the Western Ghats was studied during 1990 through 1991 and 1993 to see the spatial and seasonal variation in the ground foraging ant populations and the role of interspecific competition in structuring the community.
The diversity of ants was low compared to ant communities in the tropical rain forests in the other parts of the world at the same latitude.
Within the undisturbed forest there was no significant variation in ant community structure among different sampling sites. There was a difference in ant species between the undisturbed and the logged forest site. The resource rich, heterogeneous and successional logged forest site had more number of species per plot than in the homogenous primary forest site. The logged forest and the treefall gap sites in the primary forest separated distinctly from the closed canopy site in the primary forest in cluster analysis. A bimodal species distribution was observed among different sites in the primary and the logged forest.
There was strong seasonal fluctuation in total abundance of all species and abundances of each species. All species were low in numbers during the wet season Rare species fluctuated more than the common species over seasons.
There was a large overlap in utilizing foods of different sizes and types. There was strong interference competition in the community. Presence of a competition hierarchy was detected. Species faster in finding a food was found to be more aggressive. The behaviourally dominant species had a negative effect on the abundances of the total abundances of other species at baits. The territorial and the encounterer species dominated or monopolized at most of the baits. While the encounterer species could not coexist with the territorials at the bait, the activities of the submissive species was m t affected by the territorial species. Nest dispersion was however not affected by the strong interference competition which probably due to the arboreal nesting habit of the territorial species. Although habitat and rainfall are important in influencing this ground foraging ant community, interspecific competition does appear to influence food utilisation pattern but not nest dispersion.