Bees underwent a mass extinction in the days of the dinosaurs 65 million years ago. What scientists have learned about that die-off could help us understand today's trouble for these important pollinators. It has been thought that an extinction among flowering plants that the bees depended on was the source of the die-off. But, a model for the mass extinction that occurred among carpenter bees at the end of the Cretaceous era has been underway by Sandra Rehan, an assistant professor of biological sciences at UNH, along with Michael Schwarz at Australia's Flinders University and Remko Leys at the South Australia Museum. It may shed more light on the story.
From a press release from University of New Hampshire:
Rehan and colleagues overcame the lack of fossil evidence for bees with a technique called molecular phylogenetics. Analyzing DNA sequences of four "tribes" of 230 species of carpenter bees from every continent except Antarctica for insight into evolutionary relationships, the researchers began to see patterns consistent with a mass extinction. Combining fossil records with the DNA analysis, the researchers could introduce time into the equation, learning not only how the bees are related but also how old they are.
"The data told us something major was happening in four different groups of bees at the same time," says Rehan, of UNH's College of Life Sciences and Agriculture. "And it happened to be the same time as the dinosaurs went extinct."
"We found this mass extinction event signature in the DNA that just happened to correspond to the extinction of dinosaurs, which was a major change in the global diversity at the time," Rehan told Live Science, and the new research suggests the bee extinction lasted about 10 million years. "Bees have gone through hard times, and negative effects have occurred. We can maybe learn from the past, and learn how pollinators and plants respond to natural disturbances. If we can understand what happened in the past, it can help us understand the current perturbations and loss of diversification."
As Rehan notes, the team's findings may help us make connections to the decline of bees today including the loss of diversity and the impact of our agricultural systems. Today, bees face a deadly brew of pesticides and fungicides used in crops as well as other pollution factors including car exhaust, which has been shown to disrupt bees' ability to find food. They also face a loss of diversity of quality food sources as monocrops take over more land.
"If you could tell their whole story, maybe people would care more about protecting them," Rehan says in the UNH statement.
The need to understand -- and fix -- the problems facing bees is imperative. We humans are dependent upon these pollinators for raising our own food. Without the bees, humans are likely to starve, not to mention the countless other species that depend on the insects and their pollination abilities.
As TIME Magazine put it earlier this year in its cover story on bees, "You can thank the Apis mellifera, better known as the Western honeybee, for 1 in every 3 mouthfuls you'll eat today... As our farms become monocultures of commodity crops like wheat and corn — plants that provide little pollen for foraging bees — honeybees are literally starving to death. If we don't do something, there may not be enough honeybees to meet the pollination demands for valuable crops. But more than that, in a world where up to 100,000 species go extinct each year, the vanishing honeybee could be the herald of a permanently diminished planet."