>Here is the difference in our point of view.  I am suggesting breeding from
>these 'resistant' colonies to develop bees that can ignore the mites.
>Resistant bees are not a means of control.  They control things themselves.
>  I don't think we disagree, we are just saying different things.
 
You're right, we were talking about slightly different things. But this
idea of 'resistant' colonies concerns me. I am uneasy about the idea
that we could 'make' bees that would 'control' mites independantly of
what the mites might 'do', which is a common thread of many of the posts
I see. The relationship between a host and its parasite is a two-way
thing and both have the ability to change it. It is not true for example
to talk about A.cerana 'resisting' the varroa mite, they *co-exist*
successfully.
 
Look at some of what we think we know about the mite and cerana.
 
1. One of A. ceranas adaptations enables it to detect and remove the
reproducing mite in worker cells.
2. There is some feature of the reproducing mite that allows the worker
bee to detect it, therefore in worker brood it has 'learnt' not to
reproduce.
3. It is thought a substance in the worker bee's pupal body inhibits the
female mites egg production.
4. If the mite is detected in drone cells the bee's can't or don't
remove it.
5. The effect of the mites on the worker bee population is small, and it
does'nt matter to the bees if the drones are parasitised as they will
function perfectly well.
6. The mites first egg must be laid high in the cell to prevent it being
damaged by a mobile pupa and A. cerana the male mite death rate is much
higher than in A melifera, (84% vs 24%) possibly because of later
mobility of the cerana bee pupa disturbing the first egg. The high
mortality of the male egg is a 'good thing' as far as the mite is
concerned because it reduces the amount of inbreeding in its population
and its a 'good thing' as far as cerana is concerned because the mite
population is kept lower.
 
Kerry Clark's (Colonies surviving varroa) post talking about differences
between strains of varroa is also an indication to me that, never mind
the specifics, it is an inter-relationship we are dealing with and one
we don't know enough about. The consequence of that is that selective
breeding in this senario is quite different from selective breeding for
say, yellow bees or flying range, and much more difficult to make
successfull. We are I guess helping the bee to evolve faster than the
mite but I would be tempted to change the mite not the bee.
--
Dave Black
<http://www.guildford.ac.uk/beehive>,
Guildford, GU1 4RN.  UK.