Missed the start but its nice to see such considered prose, so I'd like
to join in !
 
In message <[log in to unmask]>, David J Trickett
<[log in to unmask]> writes
 
>Thanks to all who responded with comments or citations regarding my
query on
>whether or not resistance to TM by AFB has been detected or is
developing
>(or is likely to develop).....
>  In other words, quick drastic treatment
>preventing spread of the spores and resulting in destruction of the
>strain could be the reason we aren't seeing resistance.
 
I think this is true but there are two other things to consider as well.
First, AFB might not need a mechanism for evolving resistance because
its survival strategy is different. The spores just wait 150 years or so
for more favorable conditions to prevail. For example, suppose the
bacteria are *growing* and not (sexually) reproducing, they will not
become 'resistant' will they ? Second, we must remember that the spore
is not spread quite as easily as you might think, robbing bees are
adults and not directly involved in feeding brood and the nurse bees
only incidentally feed spores to suseptable brood, (brood food being
secreted). You need a fair number of spores to be present before the
disease is expressed. All in all, the conditions for the population
developing resistance are not as favorable as you might think. Varroa on
the other hand.........
>
>  My understanding is that it is
>never the case that AFB is removed by TM, so continuous, vs. one-time
>treatment should not make any difference in terms of producing a
>resistant strain.
 
This may not be true, and depends of course on the type of reproduction.
Resistance (as opposed to tolerance) appears in a population because
some of its members, by chance, have that characteristic. If we select
only those we may create a resistant population. It will depend on the
dominance or otherwise of the resistant gene but a one-time treatment
can allow the non-resistant gene to distribute itself again and render
the population vunerable.
>
>Andy also wrote:
>
>"There may be other things at work with AFB which some have called a
>disease of the "hive bees" because it is seldom found in the escaped
>populations. Again this could be because of the good old survival of the
>fittest rule
 
Maybe but. Its the disease of the hive bees because it is only in
beehives that the comb is not continually consumed and the spores
eliminated. The wax moth is the bee's friend (not the beekeepers).
 
>
>THis is a very interesting point.  The one person I know who has done
>literally *hundreds* of feral removals (A.M. Buzas 1/800-47-STING) swears
>that he has never seen a feral colony with foulbrood.
 
I canot claim this, but I *know* feral colonies here have (did have)
foul brood (Thankyou Varroa !!, every cloud..). I think whether you see
it is a function of when and how you look.
 
> Unless the feral populations were (are) (there still are some
>out there) already somewhat resistant to brood diseases in general
>- which is as Andy says, what you'd expect from natural selection.
 
Well, not in my opinion, see my earlier comments !
>
> Also, some strains of bees are apparently more resistant to
>some brood diseases than others.  This has been known since at least 1915.
>(My 1915 edition of Philips' "Beekeeping" states that the Italian strain
>is "vastly superior"  to the German black bee with respect to resistance
>to EFB.)
 
"Apparently" yes, but really, no. We didn't know anything in 1915 he
said with a smile. (See :-), and we don't know much more now ). And its
not fair you bringing up EFB at this point. The two diseases are so
different you should create another thread. :-)
 
Regards
 
--
Dave Black
Blacks Bee Gardens,
Guildford, GU1 4RN.  UK.