At this time of year, I keep an eye on my bees by checking their flights and the Varroa board. Today was rainy and cool so I wasn’t expecting any bees to be out, but I did want to check the boards.
The Varroa (or inspection) board sits under the mesh floor of the hive, allowing debris to fall down and gather under where the bees are active, so you can pull it out and check what’s going on. Some hives have solid floors, and this is fine as they tend to be less draughty, therefore keeping the bees warmer, but mesh floors tend to be the norm, and keeping the board in does retain the heat. Remember to take the board out at frequent intervals so it can be cleaned, otherwise gunk and muck accumulates and the bees can’t access the area to clean it, making it a perfect place for wax moth and other undesirables.
I would normally take the board out every other week at this time of year, and more frequently during the spring and summer. I had 3 hives with bottom boards to check today, and they are all quite small colonies so it is important to stay aware of their activity.
The first hive is a WBC with a swarm a friend collected from me quite early in the season – in fact I think it was my first hived swarm of the year. They are pretty grumpy and insisted on building up above the crownboard rather than on the frames, so they are not my favourite colony! They did not make a great deal of progress in the season so are just in a brood box over 10 frames.
Here is their board:
You can see that most of the activity is focussed in the centre: that brown patch is frass and detritus from the brood area of the nest. Surrounding it are little flakes of cappings showing the bees are opening their stores. There are quite a few wings from wasps that would have tried to get in to the hive from underneath, and succumbed. There are woodlice, woodlice spiders (those little white cocoons on the left-hand side of the board, slug trails and many other little creepy crawlies once you get your eye in. There is quite a bit of Varroa drop, but I don’t treat my bees with mite products so I will continue to monitor these to see how they get on.
In this photo you can see some translucent segmented threads:
These are antennae from immature larvae, which is thought to be where the bees have pulled out Varroa-ed grubs, although I must point out that I cannot for the life of me find the reference to such behaviour. If anyone can find it please comment as I am sure I didn’t dream it! Hygienic behaviour in honeybees is a complex set of traits, with stress signals from the infected larvae causing the detection and removal of those parasitised grubs and therefore an interruption in the lifecycle of the mite, which needs to use the larvae in the capped cell for food for its young, and a safe haven in which to mate. So, grubs which are taken out prevents a proliferation of mites as they can’t raise young and reproduce as they could if the bees are less vigilant. Hygienic behaviour is inherited, so by allowing natural selection to take place rather than treating, we are encouraging colonies who display some level of hygiene to exert evolutionary pressure. It IS a controversial subject, and many feel that by not treating it is somehow negligent, but having read the science extensively about how sensitive and complex the bee colony is, I strongly feel that nurturing homeostasis is the best thing we can do with so many challenges both in and out of the hive. Parallels with the importance of the natural balance regarding circadian rhythms and gut microbiota with us humans springs to mind…
Here is the second board. This hive is another WBC, and again, a small-ish colony in just a brood box covering 10 frames with a dummy board:
I have been feeding back some cappings to these bees, and you can see the remains of that on the board. The activity is concentrated at the front of the hive, and this denotes where the brood is. The left photo shows frass: the little dark rectangular deposits are insect droppings, probably from the woodlice. The (admittedly terrible!) photo next to it clearly shows the shiny Varroa mites.
The third hive is the Oak Tree bees from the National Trust. This is a longstanding colony so I am really interested to see what they do with Varroa, having never been treated. I know there is an opinion that feral colonies are not static and in fact die out and are replaced with a new swarm but I have my doubts as to how often this actually happens. In light of this, I am happy to say that these bees are likely to be coping with a Varroa load, although I can’t say what the impact of hiving them is on their health and wellbeing. The more I research tree cavities as the natural home for honeybees, the more I realise just how poor a hive is as a substitute. They are in a National, covering about 9 frames last time I looked. They have a lot of crossed comb so it’s difficult to get a proper idea of how large the nest is.
Not much evidence of uncapping so I will be giving these a small bit of leftover comb that I have. I also noticed a couple of chewed cherry pits which are clearly from a rodent, so I need to make sure there isn’t someone nesting in the combs. It is mild and dry tomorrow so I will have a quick peek under the roof. It is most likely that the mouse/vole has just been using the space to eat but I will check that all is fine in the hive itself.
If you don’t already have one, I would strongly recommend a hand lens for inspecting the Varroa board. Here is a comprehensive guide on how to choose and use a hand lens, and here is a choice, should you wish to add something to your Christmas List!
Look for damage to the mites themselves, and also try and spot any other little creatures that share space with the bees. There is currently some question as to whether predation of Varroa by book scorpions, Chelifer cancroides, occurs whilst they are on the bees themselves rather like an corvid picking lice off a grazing animal, or whether they just eat them of the inspection board. Or indeed whether they eat them at all! Here is an interesting website if you’d like to read more on the observations and research about this relationship between bee, mite, and pseuodoscorpion.
Here are the bees in their winter cluster, and there is thankfully no sign of a mouse nest!