First Record of the Dolichoderine Ant Genus Gracilidris Wild & Cuezzo (Hymenoptera: Formicidae) from Southern Brazil

Abstract

The dolichoderine ant species Gracilidris pombero, sole representative of the genus, is recorded for the first time in southern Brazil. Until now, the species was known only for the open fields of the South American dry diagonal and for a single locality in the Colombian Amazon. The specimens reported here were collected with pitfall traps in grasslands of the Pampa biome, state of Rio Grande do Sul, Brazil. This record represents the southernmost occurrence for the genus, extending its distribution in approximately 450 km to the south in the Neotropics and in almost 1,150 km to the south in Brazil.

New Records and Potential Distribution of the ant Gracilidris pombero Wild & Cuezzo (Hymenoptera: Formicidae)

“…The areas with highest probability of occurrence of G. pombero correspond largely with the distribution of the Cerrado, Chaco, and Pampa biomes of South America. Although G. pombero has been recorded several times in the Atlantic Forest, it was always found in relatively open forest sites (three cases; Table 1) or in non-forest habitats, particularly in cocoa plantations and urban areas, reinforcing the view that this species can tolerate some degree of anthropic disturbance (Guerrero & Sanabria, 2011;Feitosa et al, 2015). The expansion of G. pombero to areas of this biome may be related to the historic impact of land use change by deforestation, with the replacement of native forests by agriculture or urban centers, intensified principally during the nineteenth and twentieth centuries (Young, 2003) and which continues -at an estimated rate of 29,075 ha deforested per year (SOS Mata Atlântica and INPE, 2017) -to date.…”

“…In addition, we examined material deposited in the collection of the Laboratório de Mirmecologia in the Centro de Pesquisa do Cacau -CEPEC/ CEPLAC (CPDC) (Ilhéus, Bahia, Brazil), and which include specimens collected in the Cerrado and Pampas biomes, cocoa plantations, or urban areas. Finally, we compiled all published records of occurrence of G. pombero through a detailed survey of the literature (Wild & Cuezzo, 2006;Guerro & Sanabria, 2011;Brandão et al, 2011;Neves et al, 2013;Costa-Milanez et al, 2014;Camacho & Vasconcelos, 2015;Feitosa et al, 2015;Meurer et al, 2015;Solar et al, 2016).…”

“…was found in the extreme south of Brazil, extending its previous known latitudinal range by about 450 km to the south (Feitosa et al, 2015). Gracilidris pombero seems to be associated with relatively dry and open habitats, such as grasslands and savannas (Wild & Cuezzo, 2006;Feitosa et al, 2015). However, populations of this species have also been found in the Colombian Amazon and in the Atlantic Forest of northeastern Brazil.…”