Biting Back

While the sight of a body missing one or more legs may cause most people to shudder, nothing makes Dan O’Hanlon happier—especially when the body belongs to a varroa mite. The tiny bloodsucking parasite has been terrorizing his beehives in West Virginia—and many others across the country—for decades. So when he finds the sticky board he’s placed inside his hives littered with the amputees, it’s proof the experiment he’s been participating in is working.

O’Hanlon is the leader of the Heartland Honey Breeders Cooperative, a group of queen-honeybee breeders from eight states stretching from Michigan to Tennessee. The co-op has teamed up with scientists to breed bees that are able to fight off mites—a good idea since the parasites are developing resistance to pesticides.

Each member selects the best queens (those whose hives have low mite levels), then breeds them with drones that have an affinity for chomping off mite appendages. The goal is to create swarms of pollinators able to defend their honeycomb homes from the destructive invaders.

When a mite latches onto a bee, she knocks it off and bites it. Even if a mite is simply scurrying nearby, a bee will chomp down and tear a leg or two off. A mite that can’t crawl around and find a host doesn’t survive long, typically dying within 48 hours.

“Over 100,000 years, the bees will work this out themselves,” says O’Hanlon. “We’re trying to accelerate evolution and get all of these traits in a single, super bee.”

Varroa mites decimate both commercial and hobby hives by spreading diseases that hamper the honeybees’ immune systems. “Viruses have discovered that this varroa mite is an eight-legged hypodermic needle,” says O’Hanlon. Similar to the way mosquitoes carry and transmit malaria to humans, mites carry diseases lethal to honeybees.

About 95 percent of the country’s beekeepers are hobbyists like O’Hanlon, which means they generally have fewer than 100 hives each (most have between one and five). They may not have huge commercial operations that transport bees across the United States to pollinate everything from almonds to squash to blueberries, but if these part-timers are successful, beekeepers big and small could benefit from their mite-fighting buzzers.

From his hives at Purdue University, entomologist Greg Hunt has handpicked bees that bite, and he’s been raising drones and queens from those colonies ever since.

Breeders from the co-op have been traveling to his lab every June since 2013, carrying their prized queens, virgins waiting to be inseminated by carefully selected drones. The event’s been dubbed the “Instrumental Insemination Fest.” (“Beekeepers are weird,” Hunt says affectionately.)

In nature, queen bees gather all the sperm they’ll ever need in one go, usually mating with multiple drones in a single day. For the rest of her life, she simply taps those semen stores in order to lay eggs—as many as a million. As for the males, once they deliver their genetic packages, they die.

In Hunt’s lab, the process goes down differently. He starts outside where he has 50 humming hives. One by one, he locates each drone before it’s ever taken flight and dabs its fuzzy abdomen with airplane model paint (each hive gets a different color). About two weeks later, the drones take mating flights.

When members of the coop arrive, Hunt has someone fetch drones from good mite-biting colonies, nabbing them when they buzz back to the hive. In the lab, Hunt collects their semen in a capillary tube. Once he’s gathered about 10 drones’ worth of reproductive fluid, he knocks out the virgins with carbon dioxide, puts them under a microscope, and inseminates them. And that’s how baby bees happen.

The beekeepers take their impregnated queens home to make daughters, a large percentage of which will have the leg-munching genes. They mate those offspring naturally with drones and distribute the queens to regional beekeepers, thus spreading resistance.

So far, the results are promising. Surveys found that in hives with “Purdue bees,” 59 percent survived over the course of a year, compared to 22 percent in commercial hives. Because so many more buzzers lived, Purdue bees also produced more honey.

Co-op beekeepers are gathering hard data, placing sticky boards into the hives of queens with the leg-biting trait and those without, and then counting the number of mites that drop onto the surface. “We want to prove it; we don’t want to just say it,” says O’Hanlon.

In the meantime, the number of queens birthing biters is growing. Right now, about 40 breeders from the co-op bring home Purdue bees. O’Hanlon alone produced more than 500 queens from the Purdue lineage last year, double the number from the year before (which is double the number from 2012).

Hunt has also shared some queens with a couple of commercial breeders, who need thousands, but he’s reluctant to give out too many because he can’t produce them fast enough. “We’re a pretty small outfit,” he says.

Ideally, more and more queen-bee breeders will take up the effort. And as participation spreads, so will the number of mite legs on the sticky board.