UWRF biologists aim to help beekeepers deal with winter losses

Posted March 8, 2017

The experimental “nuc” beehive project being run the UW-River Falls Biology Department will be entering its third year this spring, continuing research looking at the best ways to deal with winter colony losses.

The project has been running since 2015, when biology professors Brad and Kim Mogen received a Specialty Crop Block Grant from the Wisconsin Department of Agriculture, Trade and Consumer Protection. The focus of the project was a hive type called the “nuc,” or “nucleus,” which is produced by splitting a large colony of bees into smaller colonies. The project simultaneously got into testing out various breeds of honeybee, to see which are most capable of surviving the winter.

“If we can start raising bees up here, that have already shown good overwintering traits,” said Miranda Martin, a fifth-year field biology student who worked closely with the Mogens on the project, “we can continue on a line of good overwintering that’s gonna greatly improve the survival rates.”

A massive problem in the beekeeping trade, particularly in the Midwest where the winters are harsh, is winter death. Statistics from the U.S. Department of Agriculture show that between October 2015 and March 2016, Wisconsin bee colonies declined in number by 60 percent. The root cause, Brad Mogen said, is unknown, but he said he suspects that a combination of pesticides, industrial migratory pollination techniques, and parasitic varroa mites could be stressing and weakening the bees.

“Think about the students,” Mogen said. “How many students that you know get so sick at finals week when they’re all stressed out, their immune system is down, they’re bummed out, right? And I’m convinced that bees are the same way.”

What tends to happen is that the bees starve towards the end of winter. Sometimes, Mogen said, there is even honey available to the bees, but because they can’t move about when the weather gets too cold, they can’t move to where the rest of their stores are and end up starving. For small-scale, hobbyist beekeepers, this constant winter death becomes extremely expensive. A package of bees consisting of a queen and three pounds of workers can cost upwards of $120.

“More than anything,” Mogen said, “it’s depressing and demoralizing, and people quit.”

This is a problem, he added, because small-scale beekeepers are important to small-scale agriculture. Many crops such as alfalfa and apples require animal pollination, and industrial migratory beekeepers (who ship their beehives all around the country), typically won’t bother doing business with a five-acre orchard.

“So the idea is to hopefully try to get people to stay in the industry… because we need small pollinators, local people to help the small orchards that are around here,” said Mogen.

Mogen has a twofold method of addressing the problem. First, he’s been working on a strategy by which small-scale beekeepers can repopulate their bee yards without having to buy bee packages: nucs. In the knowledge that they will be losing upwards of 50 percent of their hives come winter, hobbyist beekeepers can go through their bee yards in the summer and create a bunch of nucs from their strongest colonies. Come spring, hives will still have died, but the beekeepers no longer have to order packages to keep their colony numbers steady. In theory, this also means an increase in overall winter hardiness across the bee yards as the non-hardy colonies are weeded out.

“They’re meant to supplement hive losses,” said Charles Hayes, a senior biomedical science student who was tasked with creating a set of guidelines that could be used by beekeepers for managing nucleus hives.

The second part of the project has involved breeding new varieties of honeybee, in the hopes of finding a genetic line that can handle Wisconsin’s winters. Originally, five main genetic lines were being tested, each one defined by the region of the world that it came from. Martin’s job within the project was to breed queens from those five genetic lines, and plant those young queens inside newly made nucs. Theoretically, because the queen is the only reproducing bee within a hive and the most important member of the colony, this would allow researchers to rate the winter hardiness of a genetic line based on which colonies did the best.

“In all these bees, you have good and bad traits,” said Mogen. “Some of them perform very well, and some of them turn out to be really, at the end of the season, very susceptible to varroa mites, which is a real problem.”

The challenge with this part of the research, Mogen said, has been keeping the colonies separate. Bees, he said, are very hard to study. The queen mates with multiple drones, and those drones can come from anywhere within a given area, not just from her own hive. Worker bees can also “drift,” or move over to another hive simply because they like the smell of that colony’s queen better than their own. Michael Burns, a sophomore biotechnology major, worked to dispel some of the ambiguity by performing DNA paternity tests on bees from various colonies.

The Russian line of bees, said Martin, did particularly well, as did the “mutt” genetic line that the Mogens have been cultivating on campus. The line known as the “Buckfast” did very poorly, and Mogen discontinued the line in his own yard. Another beekeeper, however, found that the Buckfasts did relatively well.

Jerome Rodewald is a retired commercial beekeeper and a friend of Mogen’s who bought 11 of the experimental nucs to replace his winter losses last spring. He got a mix of Mogen’s various genetic lines, and kept them marked so that Mogen could stop by and check out how the different varieties did. The Buckfasts did better than expected. Overall, Rodewald said, he agrees that nucs are a good strategy for repopulating bee yards.

“You start out with a queen that is used to the bees that are with her,” he said. “She’s already laying, she has eggs and she has all three of the eggs, larvae and capped brood necessary.”

Finding new, long-term solutions is going to be important going forward, Rodewald said, particularly in light of the varroa mite infestation. These parasites have been making their way across the United States since the mid-1980s, and the only method to control them at present is chemicals. The problem, Rodewald said, is that the mites develop resistance to chemicals over time. For now, there is no other solution, but Mogen, he said, is making steps in the right direction.

Mogen will be continuing his research for another year, and will spend the summer further pursuing his research on the overwintering capabilities of his remaining genetic lines.