Alex Hum
Features Editor
Beekeepers are worried that bees are dying. But it should be a matter of concern for all Canadians.
Research into the genetic diversity of commercial honeybees is being conducted at York.
“This decline in population is of major concern because bees pollinate up to two-thirds of everything we eat, generating roughly $1 billion in Canada annually,” says principal investigator, Amro Zayed, an assistant professor in York’s Department of Biology.
Brock Harpur, graduate student and lead author, explains the purpose of the study.
“We all know they are declining,” he says. “Populations aren’t doing too well. There are a lot of hypotheses about what’s going on, about what could be causing their decline, and one of them is reduced genetic diversity.”
Harpur says that the historical migration patterns of bees are hypothesized to have led to the problematic lack of genetic diversity.
“Honey bees have been spread all around the world,” he says. “They started in South Africa and they’ve diverged up into Europe. From Europe, we actually brought them over to North America. The big question is: during all those expansions and movement around the world, how have their immune systems changed?”
Harpur explains that South African bees are the oldest, and have the greatest genetic diversity. Genetic diversity is reduced when bees migrate because potential mating partners are less available.
The issue is that North American bees, and almost all managed bees, are the offspring of European bees. In theory, North American bees should have even less genetic diversity as each population becomes increasingly segregated and inbred.
Domestication is typically meant to decrease genetic diversity. Harpur uses wolves and German shepherds as an example, pointing out that bred German shepherds have a much lower genetic diversity than their ancestors.
“We said, ‘Look, are managed bees actually more diverse than their ancestors?’” says Harpur. “Domestication should cause, and is hypothesized to cause reduction in genetic diversity, and so that’s what we expected to see, but that’s not actually what we saw. We saw that they were much more diverse than their ancestors.”
However, in their study, they actually found the opposite: genetic diversity increases significantly in inbred communities of domesticated bees.
The key is that most communities of bees, especially in Canada, are composed of bees from all over the world, creating a global mixture of bees in a single location.
“I can pick up the phone and I can order bees from Australia, and I can bring them back from British Columbia with me if I wanted,” says Harpur. “For the most part I can get bees from wherever I want. And when I do that, and my neighbours who are bee keepers do that, I can’t really control who these bees mate with.”
According to Harpur, male bees will gather and congregate regardless of their origins. Queen bees move away from their home colonies to mate with around 15 bees in a congregation, and then fly back to where they continue to produce offspring.
“Basically what you’ve got there is this big melting pot of genetic diversity that the queen just flies in to and does her thing,” Harpur says. “My bees could be from Australia, my neighbour’s bees are from Canada, maybe BC or Ontario. He’s releasing drones, my colonies are releasing drones, and my queen goes in there and mates with all of them.”
This is good news for the beekeeping industry. The promise of genetic diversity is a promise for stronger immune systems, better livelihood, and lower mortality rates of bees.
Bees with high genetic diversity are evolutionarily fit, and also produce more honey.
That is not to say that Canada does not need to worry. The hypothesis that lack of genetic diversity is leading bees to decline in number can be ruled out, but the rest of the mystery remains to be solved.
