Allen wrote:
>Some of those species may only get one opportunity per year to go through the
>foraging part of their cycle, but the honey bees may have made a clean getaway
>on a lorry to an area where they can recover.

You asked for specifics rather than generalities.  The situation in Nova
Scotia and Prince Edward Island, Canada,  might make for an interesting
specific.  In Nova Scotia the booming blueberry industry requires far more
hives than can be supported (economically) by the province.  That is, the
hives can no longer make decent honey crops in some parts of the province
and one of those parts is the Annapolis Valley which traditionally had the
highest bee density by far.  In Prince Edward Island a recent study
extrapolated that the blueberry industry could require 7000 hives in five
years time which is probably a few thousand over the economic carrying
capacity of PEI, which has less than a million acres of cleared land, and
much of that is in either grain or potatoes.  The honey bees here cannot
make a "clean getaway" like the migratory hives in the blueberry fields of
Maine. (Both PEI and Nova Scotia are closed to bee importation from both the
US and other provinces.)  They can move a few miles to be in a better
proximity to good forage, but it does not give them a huge advantage over
the bumbles for instance, who can also access good forage in this mixed
farming situation.  And the niche specialities of the bees are probably of
more importance.  The long tongue of the bumbles is a big advantage here
where red clover is the predominant forage crop grown.

In the blueberry fields I do not see competition between bee species.  The
honey bees are gathering nectar from the blueberries, while the bumbles are
sonicating them and gathering pollen.  Some of the solitary bees drill the
flowers at the base.

I agree strongly with Dave Green that the real threat to both bumblebees and
ALL pollinators is from pesticide misuse or overuse.  The beekeeper may move
honeybee colonies from the blueberry field here not only to access better
forage but also to avoid some of the insecticide spraying that follows
flowering.  The presence of honeybee colonies in the blueberry field has
been an asset IMHO to the bumblebees, because the growers cannot spray if
they want the beekeeper to return, and some of them did not seem to show the
same respect to their freebees.

Regards, Stan