Variable social organization among tuco-tucos (genus Ctenomys) in the opimus clade,

LACEY EILEEN; JUAN P AMAYA; CHRISTIAN G. IRIAN; PABLO CARRIZO; SHANNON L. OBRIEN; AGUSTINA A OJEDA

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Lugar: Lawrence; Año: 2022

0022-2372

Comparative studies of closely related species provide a powerful means of identifying the ecological and demographic factors associated with variation in mammalian social systems. Although most members of the subterranean rodent genus Ctenomys are thought to be solitary, the highland tuco-tuco (C. opimus) is group living, meaning that multiple adults share a burrow system and underground nest site (O?Brien et al. 2020). These animals are part of the opimus clade, a monophyletic collection of four named species that occur in northwestern Argentina and adjacent portions of Chile and Bolivia. As a first step toward generating a phylogenetically informed, comparative assessment of social organization within this clade, we characterized spatial relationships among members of a population of Ctenomys at Antofagasta de la Sierra, Catamarca Province, Argentina. Based on geographic location and natural history, these animals were expected to be part of the opimus clade; analyses of mitochondrial cytochrome b sequences from our study population confirmed this general phylogenetic placement. Radiotelemetry data revealed that the animals at Antofagasta were group living, with up to four adult females and one adult male sharing a burrow system. In contrast to other group living ctenomyids, however, individuals did not typically share nest sites. Although sample sizes were limited, our data suggest that individual males may associate with more than one spatially distinct group of females, with no overlap of areas occupied by different males. Collectively, these findings indicate that the social organization of the animals at Antofagasta differs in several potentially important ways from the population of C. opimus studied by O?Brien et al. (2020), suggesting that further comparative analyses of this sub-clade of Ctenomys will help to elucidate the factors contributing to variation in social behavior within this speciose and geographically widespread genus.