Composition, distribution, and relative abundance of ants in banana farming systems in Uganda

A survey of ant composition and relative abundance was conducted in farmers' fields in the banana growing areas of Uganda in 2003 to assess the effects of farming practices on ant species composition in banana fields. This survey was done to identify potentially important predators of the banana weevil, Cosmopolites sordidus (Germar). Work was repeated in both one wet and one dry season at all locations. We sampled at 39 farms in four regions and found 55 species of ants in pitfall traps and 24 species in fish and honey baits. When banana weevil larvae were exposed as baits, I I ant species were attracted, of which Pheidole sp. 1, Pheidole sp. 2, Pheidole sp. 3, Parture-china sp. 1, and Lepisiota sp. 1 were the most abundant. Seventeen ant species were found in pseudostems and 34 in corms of live banana plants and residues of harvested plants. High species richness and abundance especially inside plants and residues, suggest that ants are important foragers in banana plantations. Seven of the ant species found in plants demonstrated significant ability to remove banana weevil eggs artificially inserted in corms. Two species, Odontomachus troglodytes Santschi and Pheidole sp. 2, were able to remove eggs from naturally infested corms. O. troglodytes removed 33-68% of the eggs in naturally infested corms, while Pheidole sp. 2 removed 38-60%, of such eggs. The attraction of O. troglodytes and Pheidole sp. 2 to banana weevil-infested plant pieces, their close association with banana plants and residues, and their ability to extract artificially and naturally introduced banana weevil eggs from plant tissue suggest that these two species may have significant potential to consume weevil immature stages in plants and residues. [copyright] 2006 Elsevier Inc. All rights reserved.