Connection, isolation and reconnection: Quaternary climatic oscillations and the Andes shaped the phylogeographic patterns of the Patagonian bee Centris cineraria (Apidae)

SOSA PIVATTO M.; CAMPS A.; BARANZELLI M.; ESPÍNDOLA A.; SÉRSIC A. N.; COSACOV A.

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020

0024-4066

The joint effect of the Andes as a geographic barrier and the Quaternary glaciations as promoters of genetic divergence has been virtually unexplored in southern South America. To help fill this knowledge gap, in this study we investigated the demographic history of Centris cineraria, a solitary bee mainly distributed in Patagonia. We used mitochondrial and nuclear markers and performed phylogeographic and dating analyses, adjusted spatio-temporal diffusion and species distribution models, and used Approximate Bayesian Computation to identify likely historical demographic scenarios. Our results revealed that during glacial periods the Andes constituted a barrier due to the extent of the ice-sheets and the occurrence of unsuitable habitats, while interglacials allowed for gene-flow across the Andes. Secondary contact between previously isolated lineages was evident at least across two low-altitude Andean areas, being the northern one a putative glacial refugium. Our findings also suggest that C. cineraria has persisted in situ in four periglacial refugia located along the north-south transect, congruent with the maximum extent of the ice-sheet during the Greatest Patagonian Glaciation. As the first phylogeographic study of Patagonian insects, our work reveals that the interaction between Quaternary climatic oscillations and the Andes as a barrier, was the main driver of the spatial and demographic history of C. cineraria.