Large carpenter bees exhibit considerable dispersal capabilities in a
tropical semi-arid region susceptible to desertification
Abstract
Desertification is a major threat to biodiversity in arid areas of the
world, in part because many organisms in these regions are already
existing at or near the limits of their movement and physiology. Here,
we used molecular data to investigate patterns of persistence and
dispersal in an ecologically and economically important carpenter bee
(Xylocopa grisescens Lepeletier) found throughout the semiarid Caatinga
region of Brazil. We used a genome-wide approach (Restriction-site
associated DNA sequencing, RAD-seq) to gather genetic data
(>83,000 SNPs) from bees sampled from eight sites within an
arid region subject to desertification in Northeastern Brazil. We
observed low levels of population genetic diversity and differentiation
across the study region, despite data collection from sites up to 300 km
distant. Additionally, we detected evidence of a relatively severe
genetic bottleneck occurring an estimated 60 years ago. Our data suggest
that population genetic patterns of X. grisescens have been shaped by
human-mediated changes in the Caatinga, but these patterns have also
been heavily influenced by biological characteristics of this species,
such as their relatively high capacity for movement.