Hello Peter & All,
Interesting hypothesis but I need to remind all that other than a very few
people. AHB has had little actual research. Many researchers I have spoken
with say they want no part of digging though hives of AHB counting mites &
brood.
Especially with larger AHB feral populations.

When you read published information today on AHB at the end of the article
most of the information comes from source material.
I would like to see some new AHB research ( done by others of course!)

Thanks to Peter for posting and would like to post a few comments. I read
few research papers which I completely agree with. Even the book "Mites of
the Honey Bee" which I endorsed for many issues of bee magazines I did not
completely agree with. The book was done by simply gathering all the
published research together in one place. The book really helped to place
all the published mite information together.

>In Apis cerana (the original host of Varroa), mite reproduction occurs
only in the small number of sealed male (drone) honeybee brood cells.

Since the recent research of Denis Anderson the word *only* does not now
apply. Although not often Denis found varroa will move into worker cerana
brood at times.

>Consequently, mite populations within an A. cerana colony are low (<
800) and no adverse effects are seen.

Actually most researchers would suggest the small colony size, period
without raising drones AND the fact cerana uses a small hole in the cell of
drone brood to remove and control varroa as big a factor as the above.

Very little DWV and other virus seem problematic in cerana which still needs
further research as to why.

>However, mite populations in similar-sized AHB colonies stabilize at
1000–3000 mites per colony, allowing colonies to survive indefinitely,
although the resistance mechanism, until now, has remained elusive.

The above is painting AHB with a broad brush. With  A.M. scutellata might be
true although from what I have been told by my friends in South Africa
constant swarming and sbconding away from varroa leaves most the varroa in
the old nest ( which can then crash)and reduces varroa population greatly.

Some researchers I have spoken with say some hybrid crosses of African
genetics and European genetics are poor survivors. In my opinion hybrids can
perform all across the scale. If speaking of pure "scuts' in Africa then
much of what Peter has posted might be true but when using AHB ( meaning
hybrid cross) I wonder.

>The Africanized honeybee (AHB) has a unique tolerance to V. destructor
that is not present in the A. mellifera European honeybee.

Until a researcher tells us *exactly* what that might be causing a *unique
tolerance* simply a hypothesis in my *opinion*. I will say that the day
earlier post capping time of "scuts" plus smaller cell size *might* help in
varroa control. Keep varroa down and viruses are not as much of a problem
from my personal observation.

>that >12,000 mites are needed to kill an AHB colony.

So at 11,999 mites the hive can survive. Some researchers would get a
chuckle here. Mite threshold *in my opinion* has been shown to be not very
reliable.
I would like to see some proof of the above. Certainly a level at which PMS
usually appears.

>Therefore, although Deformed Wing Virus is present in AHB and A. cerana
colonies, mite populations stabilize at levels well below that required to
kill the colony.

The above is what was said back years ago. Numbers of mites = hive kill.
Only virus problems in last stages (Shiminuki).

I actually bought into the concept until I saw Parasitic Mite syndrum (PMS)
 in hives with low mite counts. The advanced virus research being done today
is welcomed by beekeepers.

Varroa problems and virus in my opinion keeps changing. Throwing many
commercial beekeepers a curve ball. Stronger mites and virus showing
up at lower levels of mites making research told us over a decade outdated.

Many of us have privately said the gap between research and what we are
seeing is getting wider. Hopefully with all the fuss about CCD research will
catch up! Last falls CCD research has made a big jump in closing the gap!

Bob


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