Last year my friend had a call in July about a swarm that had come from a big old tree. The cavity couldn’t bee very big. And the swarm was not big. http://www.elgon.es/diary/?p=235
But the bees in the tree survived the winter and was thriving this year too.
The swarm was last year strengthened with a couple of brood frames from his other colonies. It was not treated against varroa last year. It survived winter well. This year it was used as his other colonies to produce splits for sale. A couple of weeks ago he was too curious about the amount of mites in the colony so he gave it 15 grams of thymol and collected the downfall. After a week 150 mites. Under the circumstamces it’s not much at all. The bees must have some kind of trait that keeps down the number. He has had thousands of mites falling in a few odd colonies in earlier years with such a treatment – as comparison. Normally he just give his colonies 15 grams of thymol, but in the middle of August. As the only treatment in a year. He has Elgon bees and uses 4.9 mm cellsize. His winterlosses is always below 5%.
Next year he plans to breed from this colony as it is a very nice one.