From: Erik Osterlund <honeybee@elgon.se>
Date: Wed, 1 Aug 2001 09:12:55 +0200
To: BiologicalBeekeeping@yahoogroups.com
Subject: Re: Drone comb

I follow Chris

But overcrowding I think was a bigger probler esarlier in US. The number of
hives have decreased more and more over there. Why then didn't big losses
of hives due to crawlig bees (APV) appear before tracheal mites were found.
After that this mite were found sometimes 80% of the bees died during
winter and mites were found in big quantities. The stress from many hives
in an apiary or area had been there earlier, probably in bigger amount. And
APV have been identified for a longer time over there I think than tracheal
mite, but thougt of being no big problem until mites functioned as vectors.
So it have been said for varroa mites, making "holes" in the chitin for the
entry of the viruses. Tracheal mites make "holes" in the tracheal tubes....
But then also we have made it easier for the mites to thrive on our bees by
making them bigger and also making them more susceptible to viruses by
this, and overfed them with bigger cells, changing the nutrition and
composition of the body.

Erik

>It is not just coincidence that both tend to occur together. The conditions
>which favour one also favour the other so they both flare up at the same
>time. Norman did say that he and his colleagues think that (with the
>exception of AFB) all the common pests and ailments of bees are present in
>nearly all hives nearly all of the time, but at a very low level unless some
>stress causes a flare up. The stress in the case of APV and Acarine is
>overcrowding. Bailey in his "Beekeeping by Numbers" lecture with which you
>are probably familiar links the rise and fall of acarine/ Isle of Wight
>disease/ APV with the density of colonies in an area.
>
>It is noteworthy that in the US where Acarine is such a problem they go in
>for large apiaries.
>
>Chris