Bees suffered a mass extinction when the dinosaurs disappeared from earth 65 million years ago, say scientists.

The bees may have been hit by the loss of flowering plants during the catastrophic aftermath of a massive asteroid impact, experts believe.

Their findings, reported in the online journal Public Library of Science One, could shed light on the current decline in bee species.

Finding evidence of ancient bee extinction is not easy. Unlike dinosaurs, bees from the Cretaceous era have left little in the way of fossils.

The scientists overcame this obstacle using a technique called molecular phylogenetics that looks at evolutionary relationships written in DNA.

Analysing DNA sequences from four main “tribes” of 230 carpenter bee species on every continent except for Antarctica, the researchers spotted signs consistent with those of a mass extinction.

Combining these findings with available fossil evidence allowed the researchers to estimate when the extinction occurred.

“The data told us something major was happening in four different groups of bees at the same time,” said study leader Sandra Rehan, from the University of New Hampshire in the US. “And it happened to be the same time as the dinosaurs went extinct.”

The findings have important implications for the current decline in bee diversity, Rehan believes.

“If you could tell their whole story, maybe people would care more about protecting them,” she said. “Understanding extinctions and the effects of declines in the past can help us understand the pollinator decline and the global crisis we have in pollinators today.”