Twigs in the Leaf Litter as Ant Habitats in Different Vegetation Habitats in Southeastern Brazil

Vegetation structure and microhabitat availability and diversity affect ant assemblage diversity, growth, and dispersal. In this study, we described assemblages of ants nesting in twigs found in the leaf litter, comparing nest characteristics and ant colony sizes among different vegetation habitats at a regional scale. Twigs were collected in urban parks, Eucalyptus plantations, and preserved areas of native Atlantic Forest. We measured the twigs, counted the number of ant colonies, and estimated canopy openness. A total of 51,213 ants from 22 genera and 61 species were recorded. We collected 74, 141, and 283 nests in urban parks, Eucalyptus plantations, and native forest areas, respectively. The richest genera were Pheidole, Camponotus, and Solenopsis. Linepithema neotropicum, Gnamptogenys striatula, and Solenopsis sp.2 were recorded in all study areas. We found only one invasive species, Cardiocondyla wroughtonii. Typically, the canopy in urban park areas was more open, and these areas had lower species richness, lower rate of twig occupancy, and smaller diameter twigs occupied by smaller colonies compared to Eucalyptus plantations or native forest. Ant assemblages were determined mainly by vegetation habitat, followed by twig characteristics. As many ant species use twigs as nest site, twigs are critical habitats for maintaining ant diversity in the leaf litter of areas with varying degrees of complexity in the vegetation structure. However, the availability of twigs as nest resource depended on vegetation structure. In addition, twigs may increase the area occupied by the colonies of some ant species, including Wasmannia auropunctata, which was very frequent in urban parks. (AU)