Bees forage in a 2.5-mile (four-kilometer) radius of their colony and are designed to feed on multiple flowers. "Like the food pyramid for humans," Hayes says, "bees need variety in their diet." The problem is they get shipped into orchards and cropland where they are surrounded by nothing but a single crop for many miles. Beekeepers must feed them nutritional supplements, but questions remain about whether those feeds can sustain bees adequately.
For example, in nature, honey bees do not actually eat pollen. They add moisture, nectar, bacteria and fungi to ferment it and make it digestible. "We are looking at trying to duplicate the fermentation process that bees naturally use, using it with beekeeper feed, and manipulating those to improve an artificial diet," Hayes says. Researchers from his office offered bees different foods, and found they prefer fermented pollen feeds, but avoid common soy-based feeds and treat them as debris. These findings are set to be published in the Journal of Apicultural Research.
Pathogens and parasites
There is also the looming specter of illness, whether a viral infection or some kind of parasite. "We've looked for specific viruses and see them sometimes but not consistently," Pettis says. "For example, the Nosema gut parasite [which invades a bee’s digestive tract]—we see those at high levels in some bees but not in others. There doesn't seem to be one pathogen in particular that's implicated."
Israeli researchers recently pinpointed a genetically based treatment to control Israeli acute paralysis virus (IAPV), which had been the leading pathogenic suspect earlier in CCD research. Later findings suggest that the deformed wing virus (in which bees suffer from misshapen wings), Kashmir bee virus (an RNA-virus that affects a bee’s mitochondria) and other pathogens also pose threats.
Varroa mites are external parasites that weaken bees and spread viruses. To combat them, beekeepers traditionally apply miticides. Researchers at Michigan State University and the USDA-ARS's Carl Hayden Bee Research Center in Tucson, Ariz., are finding that sublethal doses of essential oils seem to offer mite-control benefits with fewer side effects.
Dozens of CCD-related studies are still ongoing across the country, examining everything from parasite control devices to the migratory stress of bouncing around on a truck in fluctuating temperatures. Answers can't come too soon for the agricultural industry. And with commercial hives affected, CCD could expand into the wild. Research now suggests that bees brought in to pollinate greenhouses could escape and infect nearby wild bees. And when wild bees are affected, scientists worry that they will no longer play the role of genetic insurance policy.
Rachael Winfree, an associate professor of entomology at Rutgers University in New Jersey, studied 23 small New Jersey and Pennsylvania watermelon farms and found that wild, native bees were depositing 62 percent of the pollen on the crops.
“Given concerns about CCD, in this region for this crop we actually have a backup plan, even if we lost all the honeybees,” she says. “Ninety percent of these farms would be okay because wild bees serve as a backup plan from the ecosystem.”