Bees evolved 120 million years ago, new study finds

A new study led by Washington State University researchers reveals that bees originated over 120 million years ago in the ancient supercontinent Gondwana, which included Africa and South America. The research suggests that bees emerged earlier, diversified rapidly, and spread widely, challenging previous estimates. By comparing genes from over 200 bee species and analyzing bee fossils, the scientists constructed an evolutionary history and genealogical models for the distribution of bees throughout history. The study was published in the journal Current Biology.

Photos of bees made using the team’s imaging system. Credit: Silas Bossert lab.

In this extensive genomic study of bees, the researchers analyzed hundreds to thousands of genes simultaneously to ensure the accuracy of their inferred relationships. It’s the most comprehensive study of bees to date, encompassing all seven bee families.

The findings confirm that bees evolved from wasps, transitioning from predators to collectors of nectar and pollen. The study identifies their origin in arid regions of western Gondwana during the early Cretaceous period, providing statistical evidence that bees originated in Gondwana and were originally southern hemisphere insects.

As continents formed, bees migrated northward, diversifying and spreading alongside flowering plants called angiosperms. They later colonized India and Australia. The study reveals that all major bee families diverged before the Tertiary period, around 65 million years ago, the era when dinosaurs became extinct.

A piece of ancient amber containing a tiny, fossilized bee. Bossert and colleagues from around the globe compared features of bees from fossils, including extinct species, in one of the broadest genomic studies of bees to date. Credit: Bossert lab.

The authors of the study noted that the tropical regions in the western hemisphere have an incredibly diverse flora, and this richness may be attributed to their longstanding association with bees. The rose family, a diverse group of flowering plants, accounts for a significant portion of the host plants for bees in both tropical and temperate regions, encompassing about a quarter of all flowering plants.

Bossert’s team intends to continue their research, focusing on sequencing and studying the genetics and history of more bee species. Their current findings represent a crucial initial step in understanding the co-evolution of bees and flowering plants. This knowledge could be instrumental in maintaining healthy pollinator populations, as there is a growing emphasis on conserving bee species.

The work paves the way for further studies exploring the historical and ecological aspects of bee evolution, shedding more light on their dispersal and establishment of their current ecological roles.

Source: Washington State University

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