Hi all

I would like to tell a story which is not intended to cast a dim light on anyone, nor present its author in a favorable one. It's just that about 15 years ago it dawned on me that our practice of building up colonies to maximum strength could be their downfall. That small to moderate sized colonies seemed less likely to succumb than the "tower of power" hives beekeepers prefer. 

Working as I was at the Dyce Lab at the time, I presented the idea to Dr. C. He dismissed it off-hand, stating that large populous colonies would always be the most healthy ones. Later, working as a bee inspector, I noticed that the strongest colonies often had the highest mite loads and were sometimes the first hives in a bee yard to catch AFB.

Fast forward to a new report by Barbara Locke (Swedish University of Agricultural Sciences, Uppsala). She has been studying so-called mite resistant bees for a long time and summarizes what is known in her article entitled: "Natural Varroa mite-surviving Apis mellifera honeybee populations." 

One of the most outstanding points made in the article can be summarized in this way: 

Importantly, all the mite-resistant populations in
this review have experienced a general lack of, or
less intensified, apicultural management.

Modern apicultural practices
actually favor parasitic transmission routes
that select for higher virulence, mainly by
preventing swarming, crowding colonies in highdensity
apiaries, and by exchanging hive equipment

Many of these natural Varroa mite-surviving
A. mellifera populations are smaller colonies than
seen in apiculture as the artificial selection
pressure for high honey yields insisted in apiculture
has been removed. The ability for colonies to
swarm might not completely prevent the mite
population buildup by the autumn, but when combined
together with other colony population dynamics
and mite-resistant traits, it can contribute
to reducing the mite population growth and improving
colony longevity.

Unnaturally high colony density in apiculture
leads to higher mite re-infestation and increased
spread of disease (Seeley and Smith 2015).
However, high colony density is not typical for
these mite-resistant A. mellifera populations.

These [natural surviving] populations
emphasize the influence that apiculture has on
the development of infections in honeybee colonies,
and consequently, by example suggest that
the most effective solution for sustainably improving
honeybee health would come from
adopting better management practices.

* * *

Comments:

Just what this means for beekeepers in general is unclear. If one regards the goal as maintaining small colonies, rather than large ones, this would be feasible. One could probably produce just as much honey with lots of small colonies as with fewer large ones, although labor might increase. 

However, if the crux of the matter is colony density, about the only thing that would affect that would be a large scale wipeout of honey bees, reducing the population to much smaller numbers than we have now. As I have pointed out, the number of colonies in the US, estimated at between 2.6 and 4 million (depending on how you extrapolate to cover the uncounted million), is probably nearly the same as one hundred years ago. 

From this point of view, it would be better for the bees if the bee industry was to fail generally, reducing the numbers to fewer healthier colonies. This was the opinion expressed by Bailey. He attributed the Isle of Wight disaster to overcrowding and the resurgence to better overall conditions resulting from far lower densities of colonies. 

PLB

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