Species assemblages and diversity of litter ants (Hymenoptera: Formicidae) along an altitudinal gradient across two vegetation types in Hanthana Forest in Kandy, Sri Lanka

Abstract

Ants account for 30% of terrestrial biomass and are highly sensitive to environmental variables. Present study investigated the effect of altitude (400-900 m) and vegetation type (mixed woodland and pine plantations in Hanthana forest) on litter ants. Two transects were laid at each of the five 100 m elevation levels. For hand-picking and litter extraction of ants, 1 m2 plots were laid at every 20 m intervals along the two sides of each transect. A total of 8689 ants in 9 subfamilies 32 genera and 56 morpho-species were collected. Subfamily Myrmicinae had the highest number of genera (15) and species (26 spp.). Genus Pheidole was represented by the highest number of species (5 spp.) while Solenopsis sp. 1 was the most widely distributed and abundant (6420 individuals) species. The mixed woodlands, regardless of elevation, were richer in ant species than pine plantations. Permutation test (ρ=0.30, P=3%) revealed a weak relationship between ant assemblages and environmental variables. Findings indicated that the difference in litter ant species assemblages and diversity in Hanthana Forest is possibly due to differences in vegetation types rather than altitude.

Keywords

• litter ants, species assemblages, altitudinal gradient, hanthana forest