New strategy | Researcher says varroa mites could be tricked into attacking older forager bees

A British Columbia researcher has helped figured out how to redirect varroa mites’ interest from younger nurse bees to older forager bees.

Erika Plettner, an insect researcher from Simon Fraser University, said the discovery won’t eradicate the mites, but the chemical compounds that mimic natural odorants from plants can confuse the mites enough to choose a forager bee instead of a nurse bee, the next best option.

“Forager bees tend to groom themselves a lot more because they are covered in pollen and need to groom it off their bodies,” she said.

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“More than likely the mite will fall off these bees.”

The mites would also have to put off their reproduction because they wouldn’t be around the brood nest.

Plettner, who worked with Victoria Soroker of Israel’s Agricultural Research Organization, said the mites are completely reliant on honeybees for reproduction.

The bees go through a larva or grub stage along with several molts and a cocoon stage. When the adult bee emerges, so does the mite. The emerged bee will eventually become a nurse bee, sticking close to the brood nest.

The mite has developed alongside the bee and is now ready to choose whom to hop onto next: a forager bee or another nurse bee.

“It’s well known that mites prefer the nurse, probably because that gets them near the brood nest where they could eventually produce,” said Plettner.

Beekeepers use a variety of methods to keep mite populations in their hives as low as possible, but most of them irritate bees. Some methods are even toxic to them.

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Plettner said the chemical discovery could be used alongside oxalic acid sprays by hanging a strip with the six dialkoxybenzenes from the combs of a standard hive.

She said her team is also researching bee pheromones.

“My group worked out how forager bees actually biosynthesize pheromones that tell the younger bees they can put off their maturation.”

In other words, an abundance of forager bees means the younger bees aren’t needed and can stay nurse bees.

“It’s almost like a job application network. They have to make sure all the jobs are done inside and outside the nest.”

Plettner plans to further develop the chemical compounds.