Bees probably originated from an ancient supercontinent earlier than originally believed.
The genealogy of bees was traced by a team of researchers from Washington State University, going back over 120 million years to an ancient supercontinent known as Gondwana. This supercontinent encompassed the modern-day continents of Africa and South America.
The researchers published their findings in the journal Current Biology, in which they proposed a new evolutionary history of bees. They discovered evidence that suggests bees originated earlier, diversified at a faster rate, and spread to a wider extent than what many scientists had previously believed.
Silas Bossert, a WSU assistant professor from the Department of Entomology, who co-led the project with Eduardo Almeida, an associate professor at the University of São Paulo, Brazil, stated that there has been a long-standing puzzle regarding the spatial origin of bees.
Bossert and Almeida's team, who worked with collaborators on every continent to assist with sampling and computational analysis, sequenced and compared genes from over 200 bee species. They also compared these genes with traits from 185 different bee fossils and extinct species, ultimately developing evolutionary history and genealogical models to understand the historical distribution of bees.
In what could possibly be the most extensive genomic research on bees up until now, the scientists examined hundreds to thousands of genes simultaneously to ensure the accuracy of the relationships they deduced.
Co-author Elizabeth Murray, a WSU assistant professor of entomology, stated that this is the initial occasion where we possess extensive genome-scale data for all seven bee families.
Previous research has established that the first bees probably originated from wasps, undergoing a transition from being predators to becoming collectors of nectar and pollen. This study reveals that they emerged in arid regions of western Gondwana during the early Cretaceous period.
“For the first time, we have statistics that the bees are native to Gondwana,” Bossert said. "Now we know that bees were originally insects of the southern hemisphere."
The researchers discovered evidence indicating that bees migrated north and diversified alongside angiosperms, or flowering plants, during the formation of new continents. Eventually, they established colonies in India and Australia. It was observed that all major bee families had diverged before the onset of the Tertiary period, approximately 65 million years ago, which coincided with the extinction of dinosaurs.
Authors noted that the tropical regions of the western hemisphere possess an exceptionally abundant flora, potentially attributed to their longstanding relationship with bees. The rose family, comprising a significant portion of the tropical and temperate host plants for bees, includes one quarter of all flowering plants.
Bossert's team intends to sustain their endeavors, by sequencing and examining the genetics and history of additional bee species. The outcomes of their research constitute an advantageous initial stride towards unraveling the co-evolution of bees and flowering plants. Additionally, comprehending the dissemination and occupation of contemporary ecological niches by bees could contribute to the maintenance of healthy pollinator populations.
Murray stated that individuals are increasingly focused on preserving bees and making efforts to ensure their survival in their respective habitats. He also mentioned that this research paves the way for further investigations into the historical and ecological aspects.
