Newswise — According to a recent study led by researchers from Washington State University, the first bees emerged over 120 million years ago on an ancient supercontinent. This discovery indicates that bees diversified and spread much faster than previously believed. The study, recently published in the journal Current Biology, offers a more accurate estimation of the time and location of the first bee evolution. The researchers successfully reconstructed the evolutionary journey of bees, determined their ancient origins, and mapped their probable global expansion.
The findings suggest that the original habitat of bees was located in western Gondwana, an ancient supercontinent encompassing present-day Africa and South America. Silas Bossert, an assistant professor from WSU's Department of Entomology, and Eduardo Almeida, an associate professor at the University of São Paulo, Brazil, jointly led the research project, addressing the long-standing mystery surrounding the spatial origin of bees.
Collaborating with an international team, Bossert and Almeida conducted gene sequencing and comparison from over 200 bee species. They also examined traits from 185 bee fossils and extinct species, enabling them to construct an evolutionary history and genealogical models for understanding the historical distribution of bees. The study represents one of the most comprehensive genomic investigations of bees to date, analyzing hundreds to thousands of genes simultaneously to ensure the accuracy of their inferred relationships. Elizabeth Murray, a co-author and assistant professor of entomology at WSU, highlighted that this research marks the first time that such extensive genome-scale data has been available for all seven bee families.
Earlier studies had already suggested that bees probably evolved from wasps, changing their lifestyle from predators to gatherers of nectar and pollen. However, this new research provides statistical evidence that places the origin of bees specifically in the arid regions of western Gondwana during the early Cretaceous period.
Bossert emphasized that this study brings forth conclusive evidence showing that bees originated on Gondwana, marking the first time they have solid statistical support for this claim. As a result, it is now confirmed that bees originally belonged to the southern hemisphere insect community.
The researchers uncovered evidence indicating that as new continents emerged, bees migrated northward, expanding and diversifying in close coordination with angiosperms, the flowering plants. Subsequently, they successfully colonized regions like India and Australia. Interestingly, all major bee families seemed to have diverged before the beginning of the Tertiary period, approximately 65 million years ago, coinciding with the extinction of dinosaurs.
The authors highlighted that the tropical regions of the western hemisphere boast an extraordinarily diverse flora, which may be attributed to their long-term association with bees. Among the various flowering plants, a significant portion, including one-quarter, belong to the extensive and diverse rose family, which serves as crucial hosts for bees in both tropical and temperate regions.
Bossert's team has future plans to advance their research by sequencing and studying the genetics and histories of additional bee species. The current findings represent an important initial stride in unraveling the intertwined evolution of bees and flowering plants. Gaining insights into how bees dispersed and adapted to their current ecological roles could prove crucial in maintaining the health of pollinator populations.
As awareness grows regarding the conservation of bees, more efforts are being made to protect and sustain these vital species in their natural habitats. Elizabeth Murray expressed that this study paves the path for further investigations into the historical and ecological aspects of bees, enabling a deeper understanding of their journey and ecological significance.
Additional contributors included Felipe Freitas, Washington State University; Bryan Danforth, Cornell University; Charles Davis, Harvard University; Bonnie Blaimer, Tamara Spasojevic, and Seán Brady, Smithsonian Institution; Patrícia Ströher and Marcio Pie, Federal University of Paraná, Brazil; Michael Orr, State Museum of Natural History, Stuttgart; Laurence Packer, York University; Michael Kuhlmann, University of Kiel; and Michael G. Branstetter, U.S. Department of Agriculture.
View the article in Current Biology.
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