Connection, isolation and reconnection: Quaternary climatic oscillations and the Andes shaped the phylogeographical patterns of the Patagonian beeCentris cineraria(Apidae)

Abstract

The joint effect of the Andes as a geographical barrier and the Quaternary glaciations as promoters of genetic divergence remains 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 phylogeographical 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 represented 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 across at least two low-altitude Andean areas, the northern one being a putative glacial refugium. Our findings also suggest that C. cineraria has persisted in situ in four periglacial refugia located along a north–south transect, congruent with the maximum extent of the ice sheet during the Greatest Patagonian Glaciation. As the first phylogeographical 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.

Genomic footprints of Quaternary colonization and population expansion in the Patagonian‐Fuegian region rules out a separate southern refugium in Tierra del Fuego

“…The importance of Pleistocene glacial periods in moulding current Patagonian species distribution is widely recognized. Most studied species (e.g., bees: Sosa‐Pivatto et al, 2020; huemul: Marín et al, 2013; lizard: Fontanella et al, 2012; frog: Nuñez et al, 2020; birds: Acosta et al, 2021) would have experienced population expansion during or after the LGM. However, most of the inferred times for rodent expansions, including a previous estimation for continental populations of A .…”

Classification of rocky outcrops plant communities in the mountains of Central Argentina

“…The most parsimonious explanation for the presence of Andean taxa in outcrops at higher elevations in our study area may be related to the well‐known effect of elevation on plant distribution (Cabido et al, 1998). However, Quaternary climatic oscillations may have influenced the connection of plant species between the Andes and extra‐Andean habitats in Argentina (Sosa‐Pivatto et al, 2020).…”

The origin and spread of the southern black ant, a widely distributed leaf‐cutting ant

“…The southern cone of South America is one of the regions of the world that has undergone a great number of complex geo-climatic events that have triggered diverse evolutionary processes of great magnitude (Arana et al, 2021), affected the distribution of the species, and impacted their demography and genetic dynamics through time (Smith et al, 2014;Sosa-Pivatto et al, 2020). The hypothesis about the origins of neotropical diversity is still a matter of debate (Rull, 2013;Smith et al, 2014).…”

“…The adaptive changes that organisms experience when they disperse through different ecological zones or environmental clines, suffering processes of contraction and/or population expansion, play a relevant role in the generation of biological diversity (Arenas et al, 2012). The southern cone of South America is one of the regions of the world that has undergone a great number of complex geo‐climatic events that have triggered diverse evolutionary processes of great magnitude (Arana et al, 2021), affected the distribution of the species, and impacted their demography and genetic dynamics through time (Smith et al, 2014; Sosa‐Pivatto et al, 2020). The hypothesis about the origins of neotropical diversity is still a matter of debate (Rull, 2013; Smith et al, 2014).…”