Cleanliness is next to godliness... Even for honeybees

Sometimes you go around to someone’s house and they make you take your shoes off, provide you with coasters, maybe hoover around you as you walk and in other peoples homes you feel like you’ve walked into a landfill. You might classify these two groups of people as either clean or unclean. Well this is also the case with honeybees. However instead of clean or unclean, they are grouped as hygienic or unhygienic colonies. What this hygiene relates too, however isn’t their ability to keep a kitchen or bathroom clean, but how efficient the colony is at removing things like dead brood, slightly more morbid.

The reason why understanding this hygienic behaviour is important is because it can help bee keepers use the colony themselves to control for certain diseases, such as the famous varroa mite. Being hygienic isn’t something these bees learn, it’s actually a genetic trait. Bee keepers are able to breed from queens whose colonies exhibit this cleaning behaviour and by doing so create more colonies which are also hygienic. Pretty handy.

That being said, how do they know which colonies are hygienic or not? Enter SCIENCE. And I mean real science, none of this catching and painting bees nonsense I do, but real science with goggles and dangerous substances. The specific dangerous substance, liquid nitrogen. Now a little disclaimer here. Sometimes in order to help protect a species and learn more about its behaviour, you have to create a few casualties. In this case, quite a number of casualties.

So what is the process? It’s actually relatively simple. All you need is, some honeybee colonies, honeybee brood, liquid nitrogen, a camera, some tin cans and a lovely bee keeper to help you.

You take out a frame (as you can see below) from a colony and check to see it contains brood (the baby honeybees).

The honeybee queen will lay her eggs in cells which the workers will eventually cap over to allow the eggs to develop into adults. These are the brood cells, the part of the colony we are interested in for this experiment. You take these frames and choose two good, densely clumped patches of capped brood and place over them two metal cans. By place I mean you squoosh into the frame, which is slightly unpleasant but the reason why you do this will become apparent. You then (very carefully) ladle out liquid nitrogen and pour it into these tin cans. Because they are squooshed down the nitrogen is contained within the two neat rings. What we are doing here is using the super cooling effects of the liquid nitrogen to freeze kill the brood.

Once that’s done a photo is taken, showing the two rings, name of the colony and the date.

Two days later the colonies are checked again, photos are retaken and the difference in capped and uncapped brood between those two sessions is calculated. If the colony is hygienic, over 95% of the freeze killed brood will be removed. These colonies have highly efficient care takers.

Why is all this important to know? I said earlier that it can help bee keepers reduce disease in colonies, but how? A study at Sussex University a few years ago found that a one year build-up of the Varroa mite in hygienic colonies was half of that in unhygienic ones. Also, in these hygienic colonies none of the bees showed symptoms of a horrible disease, deformed wing virus, however this was present in a third of the nonhygienic colonies.

So the moral of the story? When either of your parents tells you to tidy up, maybe listen to them. It could be the difference between a nice parasite free existence, or developing a wing abnormality…