The buzzing of bees was first heard 120 million years ago on the western side of supercontinent Gondwana, scientists have revealed.
And the species diversified far quicker than expected, to spread all over the planet.
Researchers at Washington State University have reconstructed the evolutionary
history of bees to discover where they came from and how they spread.
The results indicate their point of origin was in arid western Gondwana, an ancient supercontinent that at that time included what is now Africa and South America.
They believe that from their beginnings in the early Cretaceous they moved north with the new continents, following plants into India and Australia.
The team sequenced and compared genes from more than 200 bee species.
They then compared them with traits from 185 different bee fossils, as well as extinct species, developing an evolutionary history and genealogical models for historical bee distribution.
In what may be the broadest genomic study of bees to date, published in the journal Current Biology, they analyzed hundreds to thousands of genes at a time to make sure that the relationships they inferred were correct.
Previous research established that the first bees likely evolved from wasps, transitioning from predators to collectors of nectar and pollen.
Silas Bossert, assistant professor with WSU’s Department of Entomology, who co-led the project said: “There’s been a longstanding puzzle about the spatial origin of bees.
“For the first time, we have statistical evidence that bees originated on Gondwana.
“We now know that bees are originally southern hemisphere insects.
“We present a novel analysis of bee biogeography using extensive new genomic and fossil data to demonstrate that bees originated in Western Gondwana, now Africa and South America.
“Bees likely originated in the Early Cretaceous, shortly before the breakup of Western Gondwana, and the early evolution of any major bee lineage is associated with either the South American or African land masses.”
The researchers found evidence that as the new continents formed, bees moved north, diversifying and spreading in a parallel partnership with angiosperms, the flowering plants.
Later, they colonized India and Australia. All major families of bees appeared to split off prior to the dawn of the Tertiary period, 65 million years ago, the era when dinosaurs became extinct.
Bossert added: “Subsequently, bees colonized northern continents via a complex history of vicariance and dispersal.
“The notable early absences from large landmasses, particularly in Australia and India, have important implications for understanding the assembly of local floras and diverse modes of pollination.
“How bees spread around the world from their hypothesised Southern Hemisphere origin parallels the histories of numerous flowering plant clades, providing an essential step to studying the evolution of angiosperm pollination syndromes in space and time.”
Elizabeth Murray, a WSU assistant professor of entomology added: “This is the first time we have broad genome-scale data for all seven bee families.
“People are paying more attention to the conservation of bees and are trying to keep these species alive where they are.
“This work opens the way for more studies on the historical and ecological stage.”
They concluded that tropical regions of the western hemisphere have an exceptionally rich flora, and that diversity may be due to their longtime association with bees.
One quarter of all flowering plants belong to the large and diverse rose family, which make up a significant share of the tropical and temperate host plants for bees.
Their findings are a useful first step in revealing how bees and flowering plants evolved together.
Understanding how bees spread and filled their modern ecological niches could also help keep pollinator populations healthy.
Produced in association with SWNS Talker
