Honeybee research could help prevent winter die-off

Winters are tough on honeybees. Cold weather means no pollen for food, and hives can starve to death while pests and disease problems are amplified. In recent winters about one-third of all Virginia bee colonies have not survived to see spring.

Virginia State Apiarist Keith Tignor is hoping his research on greenhouse bee farming could make a difference for many hives.

“Prior to the introduction of pests like the trachea mite, varroa mite, small hive beetle and some of the diseases that have been introduced in the past 15 years, the winter losses were about 10 percent or even down to 5 percent,” Tignor said. “That’s what we want to get back to, but we’ve got a ways to go. The bees haven’t been able to sustain themselves; beekeepers haven’t been able to sustain bee populations with a 30 percent or greater loss each year.”

Tignor has been studying about two dozen honeybee hives at Virginia State University’s Randolph Farm. Some are wrapped in foam insulation and some in fiberglass battens like in a home attic. Some are housed in small high tunnels, which are unheated structures similar to greenhouses. He’s testing to see which methods, if any, help the hives stay warmer in winter.

“Honeybees are temperature-sensitive; the growth of the colony is based on the warmth of the area around them,” Tignor said. “As it gets colder, of course they shut down and cluster together. As it gets warmer the queen starts producing eggs, and they start to forage more.” Using a high tunnel, “we can start to warm up the hive a little faster … and allow those bees to progress a little further in the season.”

Tignor has temperature sensors set up in his hives. So far, the ones in high tunnels are doing well, he said, and the structures cost only about $75 each to build. But there will be several winters of experiments and studies before he has hard data to share with other Virginia beekeepers.

Research is underway throughout the United States to identify solutions to the problem of winter die-off, but Tignor said Virginia beekeepers will benefit from the in-state study.

“We have our own climate and specific geography. In order to offer effective advice to Virginia beekeepers, we need to see how these techniques play out locally.”