Thermosolar Varroa Count

Last time I checked the Berwick Solar Farm bees, I put the inspection board underneath the mesh floor to see if there were any varroa mites. As the bee groom themselves and each other, the mites drop off, fall through the mesh and can be counted. Of course, it’s only a proportion that appear, so calculations can be made as to the actual number present in the hive. As these bees were a swarm I collected from an industrial estate, I have no idea of their former life, so they could be from a feral colony or a beekeeper, but beekeepers are all different (!) so even if they were hived, I have no idea of their previous management or care.

It was a hot day at the site when Paul and I visited, and we were joined by some huge lorries carrying transformers and other impressive bits of machinery . I do love the juxtaposition of high-tech and wild there; it’s a beautiful place and the grasshoppers were humming. We checked the honeybees that were occupying the swift box, but there seem to be as many wasps going in so I don’t think that little colony have made it, otherwise they would be fending off the intruders.

I removed the super from the Thermosolar hive, as the numbers in the colony will start to reduce now that autumn is approaching and we want them to be contained in a smaller space for the winter. The queen reduces her laying as the workers reduce their foraging activity, and the change in day length and temperature becomes apparent. It’s important to remember that there is a constant flow of information from the foragers to the hive, and this stimulates/suppresses activities within the colony. This is why, rather than saying “the queen does this” or “the workers do that”, it’s more that the bees respond to relationship between the environment and their hive and act accordingly to maintain a balance. This fine-tuning is often dramatically compromised if we insist on fiddling!

Here is a photo of the inspection board. We don’t keep this in all the time, but it is really useful to get a snapshot of what is going on inside the colony without intruding, as it simply slides out from beneath the floor. There are balls of pollen, wax flakes, bee faeces (or frass, to give the technical term for insect poo), wings and other random bits of bee, wax cappings, little thrips and creepy crawlies, and you can work out where the bees are most concentrated by the amount of rubbish on the board:

There are also drips of honey and other interesting things, hence the bees hopping on to take a look!

There was unequivocal evidence of varroa. A few mites themselves, and some worker bees with short, squat abdomens: this is a symptom of deformed wing virus (DWV) which can also leave the bees with shrivelled stubs instead of wings. It is a strong colony with lots and lots of bees, so I am not concerned about the levels being too much of a hazard, but it is good that we are going to have the opportunity to monitor the drop after the thermal treatment, which I will do in the next few weeks. Apologies for the rather macabre set of pics but here are two bees with DWV, and one normal dead bee on the right. You can clearly see the difference in abdomen length:

Here are the tiny-but-shiny, chestnut-brown mites. They show up quite clearly on the yellow board, and as you can see from the bee nearby, they are a sizeable parasite, if you’re a bee:

The bees themselves were foraging well and bringing in pollen, ready to stock their larders for winter and next spring. Bee grubs eat pollen – or rather bee bread, a mix of pollen, honey and various enzymes – and it is this they need to have in quantity as well as nectar, and pollens vary in their nutritional value, hence monocrops being a mixed blessing; vast quantities but unsurprisingly not necessarily affording the right blend of nutrients. Planting a wide range of nectar- and pollen-rich flowers helps bees to ensure they have a choice to feed their colony effectively. We will return mid-September to run the thermosolar treatment, and I will report back…

Thanks to Paul for the inspection board pics.

If you are interested in understanding how to plant for bees, please see my new course: Gardening for Bees and Wildlife.

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