Washington State University's (WSU) honeybee research team will advance a study of refrigeration to fight varroa mites that harm honeybees, with help from two new grants.
First, the WSU team received a combined $200,000 from the Washington State Tree Fruit Research Commission and the Almond Board of California to purchase three 20 ft. cargo containers that will be retrofitted with equipment to control the internal temperatures and atmospheric gasses, according to an announcement.
Next, the team leveraged those grants to receive a $500,000 Agriculture & Food Research Initiative grant from the U.S. Department of Agriculture that will start in August, when the refrigerated containers will be up and running.
“Our preliminary research has been really promising related to the benefits of using refrigeration storage at different times of the year, so this is an expansion to help save the bees on a large scale,” said Brandon Hopkins, assistant research professor in the WSU department of entomology.
The refrigeration technology the researchers are developing centers around fighting varroa destructor mites, one of the leading causes of colony collapse disorder in honeybees, the announcement said.
The USDA grant includes three distinct parts:
- Using carbon dioxide to kill mites in the winter;
- Doing brood breaks, which stops varroa reproduction and makes the mites more susceptible to miticides, and
- Real-world application of these techniques with commercial beekeepers.
“We know the mites die at a level of carbon dioxide that doesn’t harm bees,” Hopkins said. “We’ve never done experiments on a scale that approaches what professional beekeepers have.”
In the past, the team has used small refrigerators that couldn’t accommodate full colonies, WSU said, noting that preliminary studies used micro-colonies. The new containers will allow them to work on a scale that’s closer to real-world conditions, accommodating around 80 full-size colonies each.
Every year, beekeepers lose a significant number of colonies; normally, more than 30% and often more than 40% of colonies are lost nationally, Hopkins said. If indoor refrigeration can level out those losses, then that provides more flexibility in the honeybee population so one crop doesn’t require 98% of all U.S. colonies, he said.
“The idea with cold storage isn’t to fix all the problems but to stabilize winter losses and make the availability of colonies more dependable in February,” Hopkins said.
The over-wintering studies will be divided into three parts over three years and will use WSU bees as well as colonies donated by beekeepers in Washington, Idaho and South Dakota, the university said. One-third of the bees in this study will be put into refrigerated storage for around two months. Another third will be stored outside in winter conditions. The final third will winter in California, the most common method northern beekeepers use.
“It’s really expensive to over-winter in California, but we know how that works, so that’s the control,” Hopkins said. “We don’t know for sure if storing so many bees close together for two-to-three months in refrigeration will lead to more disease transmission or have other consequences.”
Hopkins and his colleagues will spend three years refrigerating bees to find out, and the results could have a huge impact on helping save the bees.