Harry Goudie a écrit:

> I like the idea of the mites falling through spaces in the bottom of the
> hive but I wonder if it may be possible that the feral colonies are
> surviving because of swarming.  One of the differences between a feral and
> domestic colony is that the latter is managed to prevent swarming.  If the
> swarm clusters for any length of time it may be that the temperature inside
> the cluster is sufficiently high to either kill or at least make the varroa
> uncomfortable and fall off.  The swarm may then start off in a new site with
> comparatively few varroa.
> I read somewhere about a man who had a swarm land on his head.  One of his
> comments when asked about his experience later was that it was very hot
> inside the swarm!
> Harry
> http://www.luichartwoollens.freeserve.co.uk

A few years ago, I read an article in an issue of the French edition of the
“Scientific American” about swarming. The author had measured temperature
inside the cluster from the center to the periphery. As far as I remember, he
found that the center temperature was rather hot, but not more that inside the
brood chamber. Therefore, it should not be harmful for varroa mites. Moreover,
when colonies are treated against varroas mites, it remains only a few of them
but 6 months later, you have to treat again.
Jean-Pierre