Thrice out of Asia.

Excited to announce that the first chapter of my PhD dissertation was published December 3, 2021, in Science Advances. The article can be accessed here.

The honey bee (Apis mellifera) is a prolific pollinator that has been introduced worldwide due to the apiculture industry. Although the species is found globally, it is native to Europe, Africa, and Western Asia. Over the past several decades, there has been considerable debate surrounding the ancestral origins of the honey bee species (Apis mellifera). The competing hypotheses include the Out-of-Africa hypothesis, which suggest the species originated in Africa and then colonized its current native range via two to three routes, and the Out-of-Asia hypothesis, which suggests the species originated in the Middle East and then colonized its native distribution via two to three routes. You can read more about this debate here. In this article we add to this discussion and present strong support for the Out-of-Asia hypothesis. Our hypothesis posits that Apis mellifera diverged from other honey bee species in Southeast Asia before migrating to Western Asia. From there, the species colonized its current distribution through three routes: two independent routes into Western and Eastern Europe, and one route into Africa.

In addition to investigating the origins of Apis mellifera, this article identifies specific genes associated with the species' adaptation to its wide geographic distribution. We propose that the adaptive radiation of the species was accompanied by repeated selection acting on a common set of genes. This finding parallels results from a recent study that showed repeated selection on genes in another honey bee species, Apis cerana. This paper can we found here. Furthermore, our research reveals that genes related to the species' adaptation are predominantly associated with worker traits. This observation supports previous findings (here) and suggests that the extensive contribution of worker bees to the success of a honey bee colony is responsible for this pattern. Worker bees perform crucial tasks such as brood care and resource provisioning, tasks that are essential for colony success.