--snip--

Beekeeping, like politics, is local. What works fine in one area may not
in another because of local conditions. We keep talking 4.9, but it
seems that size is more associated with the tropics and warmer climates
than the 5.0+ of temperate and cold climate bees. And in each case, the
size is not in concrete, but is a range of sizes. Why, I do not know,
but my guess is local conditions.

--snip

For my MSc research I looked at size and shape variation among many colonies of honey bees across south-east Asia.  Size was more variable within species and within races than between species and was strongly correlated with altitude.  The general biological rule is that (warm-blooded) organisms in cooler areas are stouter, in warmer areas lankier (basically less surface area to mass vs. more surface area to mass).  To make a bee stout you have to make it bigger.  Since the effect of altitude and latitude on climate are similar, you will find a range of bee sizes wherever you find a change of climate, no matter what race of bee, no matter whether in tropics or temperate zone.  The interesting part is that a bee, a cold-blooded creature, follows a rule derived and applicable really only to warm-blooded organisms.  I guess it is because they regulate their hive temperature for some of the same reasons warm-blooded animals regulate their body temperatures.  From this I would imagine that to change the size of a bee's body by manipulating its cell size would have rather profound effects on its behaviour.  Too large bees would need fewer to keep the hive warm, and too small would need more.  I would think that very small bees (such as those forced onto 4.9 comb size or smaller) would have difficulty for this reason in colder climates.

How quickly do bees, once they are allowed to freely build comb the size "they want", go to a size that is optimal given their climate?  The genetic differentiation among races suggests that they have not mixed much during their evolution and have evolved to suit their local climactic conditions.  If that is the case, their response to climate may not be as complete as it should be: if you take an Italian bee from the sunny Mediterranean and stick it into central Manitoba, without manipulating its cell size by giving it pre-formed foundation, will it ever make comb the size it should given its current climate rather than the one it evolved to live in?  It depends on how much genetic product is open to modification by environmental pressure.  Has anyone done a study that looks at the same race of bee, kept in many different climates and not forced to build a certain size comb?  It would be interesting to know if they make a range of comb sizes that matches that of native bees covering the same climactic latitude, or if they are constrained given their evolutionary history to making comb only in a limited range of sizes.  In that case maybe to survive in non-native climates they need to be forced onto large combs, or small combs, whatever the case may be.  If they have the capacity to completely respond to climate by choosing the right cell size then maybe we ought to just leave them alone - they will make the cell they need.  Of corse then someone imported varroa and made the whole thing more difficult...

Anyways, I am not yet a practicing beekeeper so maybe I am saying things everyone already knows...I did a quick web search and didn't find what I thought I had seen somewhere before - a map of "ideal" cell cizes for Canadian climate regions.  Does anyone know of this?

Martin