The fall of bees

With honey bee numbers dropping, scientists are looking at ways to reverse this trend. One culprit they are looking into is the Varroa parasite. This mite can only reproduce in a honey bee colony, and can weaken bees by sucking fat from their bodies.

The University of Sussex’s Laboratory of Apiculture and Social Insects (LASI) launched a 3-year study, funded by honey-maker Rowse, into building bees’ resistance to the mite. They achieved this by breeding ‘hygienic’ Dark European honey bees, as hygienic colonies have a better chance of survival.

The solution…

The ability to create hygienic colonies is a genetic trait in bees. Worker bees in hygienic hives will detect, uncap and remove infected larvae, allowing the hive to survive. But not all bees do this important task.

The team at LASI wanted to find a way to see which bees were doing it and to breed a line of fully hygienic bees.

They do this by freeze-killing infected sections of combs to remove infected larvae. The comb is removed and a tin can placed over the infected area. It’s then frozen using liquid nitrogen, killing this part of the hive.

The comb is then put back into the hive. After a period of time beekeepers check to see if 80% of the dead cells have been removed by the bees. If the bees have removed this amount or more then the hive is classed as hygienic.

To help this process, LASI used liquid nitrogen. Accessing the liquid nitrogen was easy for LASI as BOC, a member of The Linde Group, is their long-term supplier of liquefied gases.

Using BOC’s liquid nitrogen had a couple of key benefits…

  1. Safety first

Cryogenic fluids can be hazardous if not handled safely. Fortunately for LASI, BOC staff provided advice on the best and safest ways of handling products.

Paul Charles, a Cryospeed® and OnStream Specialist, said: “At -96°C, liquid nitrogen can give you frostbite. As a gas it’s also an asphyxiant, which needs to be stored in a room that’s fully ventilated, not under the stairs.”

Paul helped provide amateur beekeepers with the skills and knowledge to handle the product safely – including where to store it and how to obtain it.

Liquid nitrogen is easy to get hold of. And while amateur beekeepers aren’t BOC’s biggest market, it was important that they knew how to handle it safely no matter where they acquired it.

  1. Control and measurement

Another key benefit of using liquid nitrogen is the higher level of control and data measurement you get compared to conventional methods.

By using a tin can and liquid nitrogen, beekeepers can select exactly which areas they want to study. Using heat instead means that some of the edges around the can would also be affected, while the integrity of the cells would be damaged. As an amateur, liquid nitrogen gives you professional levels of accuracy. 

Spreading the knowledge

While the results of LASI’s study were positive, getting these new techniques out to the wider beekeeping world was a challenge.

“It occurred to us that as part of our outreach activities, beekeepers would have an interest in learning about the technology in workshops,” said Norman Carreck, research scientist, University of Sussex School of Life Sciences.

A two-day training course was held and Paul put together a pack of details and safety documents usually given to new BOC customers.

Norman said: “Using liquid nitrogen is easy for us to do as a university, but not so easy for individual beekeepers. BOC showed that beekeepers could get together and use liquid nitrogen safely.”

Discover BOC’s Cryospeed liquid nitrogen service today