Peter Edwards wrote

> Does anyone know if V.d. can, or has, transferred to cerana?  If so, can
> cerana cope with it in the same way that it copes with V.j.?

Talking with Dr. Denis Anderson he has done a lot of work on varroa and
cerana.  I am not sure if he has published this information but I hope I am
quoting him correctly.  Firstly VD is found naturally on cerana.  There are
at least two haplotypes of VD.  The Korean and Japanese types reproduce on
Apis mellifera.

There are a lot of haplotypes of varroa.  Each is specific to a strain
(right word?) of cerana.  So this means that Varroa destructor will only
reproduce on one strain of cerana.  VD cannot reproduce on the strain of
cerana that is the natural host of say Varroa jacobsoni and vice versa.

Denis has given us examples of VD in Vietnam (as I recall) that was
reproducing on Apis mellifera but not on the local cerana.  However there
was a haplotype of varroa reproducing on the local cerana that was not
reproducing on AM.

This is not to say that VD will not be found in the hive of cerana that
hosts VJ.  It is just that it cannot reproduce in the same way that VJ does
not reproduce on AM.

This has good repercussions for our quarantine work here in Australia in
that previously we had to get the actually varroa to find out if it was VD
or VJ.  Now we need only have a sample of bee and the DNA will give us which
varroa it is the natural host for.  So surveys offshore will let us know
where the threat from varroa is coming from.  This is crucial in the north
where Indonesia is shifting hives of cerana around from island to island as
part of a re-settling programme.  Whilst they are shifting cerana that host
VJ we are safe but when they shift cerana that hosts VD then we need to be
viligent.

ope the above helps.

Trevor Weatherhead
AUSTRALIA

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