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Informed Discussion of Beekeeping Issues and Bee Biology

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Subject:
From:
Karen Oland <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Sun, 1 Dec 2002 15:20:04 -0500
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> From: Humdinger
>
> My original thought in the thread was that by treating bees, for whatever
> diseases they suffer from, we are doing, in a way, “a Selective Breeding”
> of an isolated EHB species that cannot and will not survive on their own—
> without human intervention.

There are several problems with your proposed solution to the problem of
mites and SHB in managed honey bee colonies.  Leaving aside your analogies
between parasitic pests (mites, beetles) and microbes (mostly viruses, but
you included bacteria, which are the only ones treatable with antibiotics),
the main fallacy in your reasoning is that there is some guarantee that
managed honey bees (apis mellifera in this discussion) will survive their
encounter with these new pests.  Certainly, there is no evidence that they
have done so in the past (ie, there are no native apis mellifera in the
"native" ranges of the varroa mite, although there are now, due to
introduction by man).

It is true that no parasite benefits from killing all of a host species.
But, when a parasite transfers to a new host, there are four possibilities:

1) The parasite is unable to properly reproduce or grow on the new host and
remains a very minor problem or even eventually dies out, with only new
transferrals being found in the new host population.

2) The new host provides essentially the same environment as the original
hosts and a balanced relationship is created.  This state could also be
achieved through selective breeding (natural or artificial), providing there
is some genetic characteristic that is available in the host).

3) The parasite kills most of the host population, but not all. This could
eventually lead to achievement of the same balance as in case 2, starting
with a vastly depleted population (which would then most likely be more
vulnerable to another pest later on, due to reduction of genetic diversity)
or could lead to small pockets of the host existing despite the parasite,
with waves of parasite infestations decimating these in turn.  The end
result could be hives of bees that survive, but do so due to characteristics
that make them useless for pollination and honey production (for example, if
the survival characterstic is extreme aggression or small population or
constant absconding, then the resulting bee may not be useful).

4) The parasite kills 100% of the host population.  Given enough spread of
the parasite to the new host (either due to natural or artificial spread),
this results in extinction of the host.  When you look at native ranges of
different Apis species, this type of selection _could_ have been responsible
for the absence of some species from areas where you might otherwise expect
them to live (and it may not, without some evidence one way or the other,
why certain species are found only in certain areas is pure speculation).

With "microbes" (mostly viruses), the same general principles can apply as
to spread within the population and possible consequences of the encounter
(bees could shrug them off, live with them well or badly or the  virus could
win and the bee become extinct).  Evolution does imply that survivors will
pass on their survivor genes, resulting in some type of balance; however,
there is no guarantee there will be any survivors or that the survivors will
be from a particular species (look at the many thousands of extinct species
that did not adapt to changing conditions throughout history).

> By religiously treating bees with expensive chemicals that often lose its
> efficacy incrementally, we are trying desperately to delay the eventuality
> of the contact forever while weakening the bees even further.

If there were some guarantee that honey bees will survive their encounters
with these new pests, then this would be absolutely right on.  Any treatment
would not only delay the survivor genes from becoming dominant, it would
also allow faster spread of the pest (whether parasite or microb) to further
populations.  However, if there is little chance of the bee surviving such
an encounter (and 100% death rates in non-treated apiaries would tend to
support that view), then treatment either allows time in which to engineer a
survivor capable bee or enables the bee to survive period (with no end to
treatment withought some genetic change to the bee).  Unfortunately, the
only way to test for new survival genes is to  stop treating and see how
many die -- a project best suited for research and not those depending on
bees for survival.  Just as movement among human populations now enables a
virus to decimate worldwide in very little time, movement of bees enables a
pest to spread much more rapidly than evolution's usual time period for
exposure (contrast the spread of the flu in 1918 to the spread rates in the
middle ages, when most men traveled less than a few miles from their homes
in their entire lives or today's Ebola spread in a village that travels on
foot versus one that's members travel in cars or planes)

> I suggest we accelerate the eventuality by not treating them at all or
> bringing in whichever bee species that had learned to live with such
> pathogens—-a reason I had, in the first place, asked to hear from for
> those who have not treated the bees for a while.  AHB seems promising,
> especially since by the time they spread into most of the southern states,
> their super-aggressiveness will have thinned out.

>From what I have read, there has been very little change in the
aggressiveness of AHB as it has spread (although there has been less panic
spreading press).  AHB seems to tolerate varroa -- but their very
agressiveness may be the reason why.  Or their practice of absconding (which
leaves behind the population of larva that is infested, carrying only adult
mites to the new location).

SHB may be unable to survive the desert conditions of the southwest (due to
extreme low humidity) at more than minimal levels.  So, you might end up
with a balanced population of AHB and  the current pests of mites and SHB in
the desert southwest regions.

But, taking AHB from the southwest that deal with both varroa and SHB well,
may result only in a bunch of ill tempered bees that are overwhelmed by SHB
in more humid areas and that produce little honey or pollination value due
to their tendency to swarm.

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