An arboreal ant that inhabits tunnels is recorded for the first time in the South region of Brazil

Resumo

Crematogaster is a hiperdiverse ant genus occurring in many terrestrial ecosystems around the world. Most of the Crematogaster species are arboreal ants, occupying a variety of forest and open environments and possessing a variability in habits and behaviors. However, Crematogaster stollii is the only species within this genus to construct and live inside of tunnel systems in the trees it occupies: the workers are never found exposed to the tree trunk surfaces but, instead, they are always foraging inner to such tunnels. This species occurs mainly in the Amazonian region and has no distribution below the Tropic of Capricorn. In our study we recorded this tunnel making behavior for the first time in another but similar species (Cr. aff. stolli), occurring in the South region of Brazil. We suggest this is a new species for the genus waiting for a description and provide data on the tree species where the ant occurs; the behavior of constructing tunnels, distribution on the trees, as well as the description of structures functioning as nests. We encourage mirmecologists to explore more the ant fauna from the South region of Brazil, emphasizing agricultural fields containing associated natural forests. The region may harbor still not explored ant species, as well as intriguing and unexpected behaviors, such as the one we reported here.