Comparison of Ants (Hymenoptera: Formicidae) Diversity in Dry Dipterocarp and Mixed-Deciduous Forests at Sri Nan National Park, Northern Thailand

Abstract

The species diversity of ground ants (Hymenoptera, Formicidae) in a section of mixed deciduous and dry dipterocarp forests within the Sri Nan National Park, northern Thailand was investigated using hand collecting, leaf litter sifting, and pitfall traps. A total of 121 species belonging to 41 genera in 7 subfamilies was recorded. Thirteen species were recorded in the richest genus Camponotus. From the pitfall trap data, the means of ant species diversity indices in the mixed deciduous forest were significantly higher than those in dry dipterocarp forest (p≤0.05) in both the winter and summer (but not the rainy season), whilst the mean ant dominance indices were not significantly different between the mixed deciduous and dry dipterocarp forests in the summer and rainy seasons (p≤0.05). However, the mean dominance index was significantly higher in dry dipterocarp forest in winter than that in the mixed deciduous forest (p≤0.05). Anoplolepis gracilipes (Fr. Smith, 1857), an exotic species, and Odontoponera denticulata (Fr. Smith, 1858) were the most frequently found species in both forest areas. In summer, pitfall trap data indicated that the populations of both species were significantly higher in the mixed deciduous forest than in the dry dipterocarp forest (p≤0.05), but in the winter, Anoplolepis gracilipes populations were not statistically different between the two forests. The implication for using some ant species as bioindicators in each forest type as well as sampling methodology is discussed.