Ant (Hymenoptera: Formicidae) Diversity in the Canopy of a Tropical Dry Forest in Tepoztlán, Central Mexico

Abstract

The canopy of the Neotropical forest hosts a wide diversity of arthropods, where ants represent one of the most abundant and diverse groups. This diversity may be due to the preference of some insect species for certain species of trees. In order to determine the diversity of ants and their patterns of association with trees, nine tree species of two zones (soils based on limestone or volcanic rock) of the tropical dry forest were chosen in San Andres de la Cal, Tepoztlan, in Morelos state, Mexico. Ants were collected directly from the branches of 5–10 individuals per tree species or by using pitfall traps. Estimated sampling efficiency was 96%, and a total of 27 species of ants belonging to 13 genera and 6 subfamilies were found. Of these species, 56% are tree-dwelling while the rest are generalist species that climb the trees to forage in the canopy. Ant species richness differed among tree species, with a gradient from Ipomoea murucoides with the highest richness, to Bursera fagaroides with the lowest. No differences were found among the tree species in terms of the composition of ant species, but 44% of the species were found in one forest zone only and one species was found more frequently in one zone than in the other. With the information generated in this study, eight species and one genus (Tapinoma) have been added to the 89 species and 29 genera recorded in the state of Morelos. While ant species composition did not differ among tree species, the difference in richness suggests that three of the studied tree species offer a greater provision of resources to the ants and that the floristic differences between forest zones generate different ant assemblages.