From: "T & M Weatherhead" <queenbee@gil.com.au>
Date: Thu, 4 Jan 2001 20:59:13 +1000
To: <BiologicalBeekeeping@egroups.com>
Subject: Re: observations.

Members on this list may not be familiar with the recent work by Dr. Denis
Anderson here in Australia. Dr. Anderson has re-classified the varroa
family and we now find that the Varroa jacobsoni does not in fact reproduce
on Apis mellifera. It can only reproduce on Apis cerana and a specific
species at that.

The one doing the damage to Apis mellifera is now called Varroa destructor.
There are several hyplotypes and the most damaging is the Korean type.
Varroa destructor is again specific to a certain type of Apis cerana. Dr.
Anderson has been able to match the different Varroas with the different
cerana. Look for some papers soon on the distribution of Apis cerana.

So the question arises as to why only some of the Varroas have made the
transition to Apis mellifera. Even if larger cell sizes are available,
Varroa jacobsoni will not reproduce in Apis mellifera. It can be found in
cells of Apis mellifera but something does not trigger the egg laying, even
in large cells, like Varroa destructor does.

It is thought that maybe there is a chemical response that triggers the egg
laying.

The question is also raised as to why varroa destructor will only lay in
drone cells of Apis cerana but in both workers and drones of mellifera.
David Eyre has raised the question as to why varroa are not reproducing in
queen cells of mellifera.

Dr. Anderson is ongoing in his work and I believe that since the publication
of his paper, there are other scientists around the world re-looking at the
whole varroa question.

Is it just cell size that can stop varroa destructor reproducing in Apis
mellifera workers? Is it "resistance" such as that being breed for tracheal
mites in Ontario? It is an interesting question but I would not rule out
some chemical response as most bees are governed a lot by pheromones. It may be that control of varroa will come about by some pheromone that
disrupts the ability of the varroa to lay eggs and this would certainly be a
biological control method. No residues here.

Just another thought for consideration.

Trevor Weatherhead
AUSTRALIA