Mild Weather After Christmas.
After some heavy frosts, things warmed up to around 10 degrees Celsius on 28th December and all the colonies became very active. Next day was even warmer with 14 degrees C recorded on the Moray Coast. It was like a spring day but with no forage available, apart from some distant gorse which is always in bloom. However, I’m pretty sure that the bees were intent only on relieving the pressure in their rectums and getting rid of weeks of accumulated waste.
I was sitting by one hive when a caramel coloured fex (bee faeces) hit the side of the hive with an audible splat. Curious to know what it contained, I collected a sample on a glass rod and placed it on a microscope slide. I added a drop of water and mixed it around before placing a coverslide on top and viewing under my microscope at 400 times magnification. I didn’t find any nosema spores which was good news and the specimen was packed full of pollen grains. It was difficult to identify them all but there were lots of pillow-shaped Himalayan balsam pollen grains. The bees had been down by the River Nairn from late July to early October collecting it by the basketful. You can see examples of these, and many other beautiful pollen grains on Ian Jobson’s excellent website: http://www.northumbrianbees.co.uk/
Finding so much pollen was a surprise to me because I know that winter bees have well developed fat bodies and can live for a long time on a diet of carbohydrates (honey & sugar) so might have little need for protein at this time. Also, there is usually a lull in egg laying and brood food production in November/December so little pollen is thought to be used then. However, on investigating I came across work by Randy Oliver suggesting otherwise. http://scientificbeekeeping.com/. Randy sampled winter bees and found that each had guts full of pollen. Maybe my bees never stopped eating pollen and that this is how winter bees prime themselves for the onset of egg laying around the solstice.
We have some interesting terminology in beekeeping and a cleansing flight is when honey bees take advantage of milder winter weather to get outside and defecate. Unless sick, bees don’t usually defecate inside the hive. What usually happens is, they hold onto waste which builds up in the rectum filling it to capacity until conditions are right for voiding outside. However, sometimes after a long confinement the faeces are explosively disharged inside the hive, or around the outside. Water collects in the gut from the digestion of honey. Some water is reabsorbed by diffusion from the mid gut (ventriculus) when the haemolymph water concentration falls, but water not reabsorbed collects in the hindgut or rectum and stays there until the bee defecates.
This is another strange but commonly used beekeeping word. It is strange because it often doesn’t convey the true meaning of the situation. Dysentry is an infection of the intestinal tract and honey bees do not necessarily have an infection when they void forcibly after a long confinement. Sometimes they have nosema and are infected with microsporidial fungal spores but dysentry is not a symptom of nosema. We could use the alternative term diarrhoea but this is not accurate either because diarrhoea is the passing of frequent loose faeces and the bee usually voids the contents of the gut on one occasion. I’ll stick with dysentry until someone comes up with a more accurate term.
Causes of Dysentry.
Dysentry in honey bees arises because there is too much water in the faeces. It is due to the consumption of dilute food or water during confinement to the hive.However, it can happen during bad weather over the active season when bees cannot get out to fly. Even a short confinement while feeding on unripe honey can create a problem. When the waste collected in the rectum reaches 33% of the total weight of the bee dysentery appears, states Randy Oliver. Apparently, fermenting syrup, pollen, dextrin, minerals or burned sugar don’t cause dysentry.
What Can a Beekeeper Do.
Unfortunately, we can’t control the weather and long confinements over winter. However, we can ensure that our winter preparation feeding is not dilute. Crystalised honey/syrup stores produce water because they divides into a solid crytsalised part and a liquid part with the latter containing excessive water, so we might remove crystalised stores and feed them back to bees during good weather in the active season.
The New Year.
I hope your bees had a chance to get out recently because it is also a great time to assess the condition of the colonies without disturbing them. It’s reassuring to know that they have had cleansing flights and can tolerate better further waste buildup during the inevitable cold winter weather yet to come. Also, it is nice to know that they are healthier from having had a good purge.