Honey bees face a lot of challenges, according to Steve Sheppard, professor of entomology at WSU. Invasive mites can sap a brood’s strength and bring in viruses. Pesticides can build up in the brood comb and weaken the bees. And, while the agricultural practice of monoculture provides a lot of food, it offers little of the nutritional variety that bees need. Some of these threats alone may weaken or kill a hive, but a combination of factors is thought to be the cause of colony collapse disorder, in which worker bees abruptly disappear and the entire hive is doomed.
Plant and animal breeders seek resistant specimens to selectively breed, incorporating their resistance into the overall population. But U.S. entomologists have to work with a limited honey bee gene pool because of a 1922 import ban on live honey bees to restrict a concurrent influx of mites and viruses that threaten native bee populations.
“Honey bees, Apis mellifera, have 28 recognized subspecies in Europe, Africa, and Asia–the area where honey bees are thought to have originated,” said Sheppard. Evaluation of this wide genetic diversity by U.S. bee breeders was effectively halted by the 1922 import ban.
In an effort to find the needed genes, the USDA granted WSU a permit in 2008 to import honey bee semen for breeding purposes, subject to strict inspection. The imported semen is tested for viruses, and queen bees inseminated with the approved semen can then be released to bee producers.
While semen extraction and insemination of honey bees is known technology, preservation of the semen has always been a challenge. But Sheppard’s graduate student Brandon Hopkins discovered that liquid nitrogen maintains the semen viability for decades, helping preserve imperiled subspecies in a honey bee genetic repository.
– by Bob Hoffmann
Learn more about honey bee research at WSU.