A couple of months ago I was contacted by a builder who had encountered a nest of bumble bees (Bombus lapidarius, the Red Tailed Bumble Bee) in a wall of a barn in Powerstock that he was converting. I took a look, had a chat with the owner, and returned later with a bird box that had been sat in the bee bole in my garden for years without being occupied. Gently I removed the stones and exposed the nest, which I scooped into the bird box, which I then returned to its usual place in the bole. They seemed to cope with their enforced move and I see the occasional bee flying from it. They have ‘rearranged the furniture’ as a lot of the nesting material has been thrown out of the entrance.
All seemed well enough and they didn’t need any more interference from me, However, some days ago, I saw walking on the podium in front of the box a bumble bee that must have had no option but to walk as her wings were missing on the right side. I picked her up and noticed that she was covered with what appeared to be mites
I put her, mites and all, into a pudding basin, sealed with a plate, and put it in the fridge, assuming that they would all very soon be humanely killed, enabling me to examine them. For days afterwards, every time I took a peek they were moving, prompting me to drop the sensor of an electronic thermometer into the bowl next to her. 45 degrees Fahrenheit, so maybe that upper end of the fridge is a little less cold than is ideal.
Today I looked again and found all dead so I transferred them to a pot under a magnifying glass. The mites are similar in shape to Varroa mites but very much smaller and so must be a different species. I’m wondering whether Deformed Wing Virus, which afflicts honeybees, having been transmitted by varroa might also affect Bombus through a similar process.