For around a decade, beekeepers have seen around one-quarter to one-third of their colonies die every year. There are many potential causes for the die-off, but most scientists agree a parasitic mite is a major factor.
Purdue entomologist Greg Hunt says if a bee were human-sized, the mite would be about the size of a balled-up fist. Other scientists say the size is more comparable to a pancake.
But now, Purdue University scientists have bred special bees that are biting back.
Hunt raises millions of bees just West of Purdue’s campus. They have one thing in common-they’re particularly good at protecting themselves. Purdue scientists have selectively bred the bees to chew off the deadly Varroa mites that suck blood and transmit disease.
“The bees are fighting back,” he says. “They’re fighting the mites, they’re removing them from themselves, and we find that about 45 percent, on average, of the mites that are falling off have their legs chewed.”
Hunt and his colleagues have been breeding the special mite-biters since 2007.
After selectively breeding the special grooming behavior, Hunt says the so-called “mite-biter” bees have exhibited twice as high a survival rate as commercially-available bees and one-third of the mites as the non-biters.
“We’ve selected for this trait and increased it from an average of three percent to forty-five percentage chewed mites,” he says. “And it seems to help because now we don’t have to treat our colonies at all to kill the mites.”
During its annual “Artificial Insemination Fest,” Purdue makes the genetic material from the mite-biter queens available to serious beekeepers, who then breed and distribute their own hygenic honeybees.