>Do migratory beekeepers stop at the 35th parallel?

Of course not.

My point really was addressed at the likelihood of the bees becoming
ESTABLISHED outside their apparent viable range.

No doubt they could quite easily be brought into any area by migratory
beekeepers, and would probably do fine in the summer, but for whatever
reason something stops them establishing outside that range permanently.

They have not apparently done so in Argentina (perhaps a local
respondent out there could add their comments on this) which also has
migratory beekeeping.

I should imagine that regular (both assisted and natural) incursions
north of their line will take place every year, followed by dying back
in the winter. (As an aside, migratory colonies could be well on their
way back south before this phenomenon kicks in, possibly leaving genetic
havoc in their wake amongst resident colonies in the north.)

Exactly where that line will lie in a North American environment remains
to be seen however, but the slow down in their progress since crossing
the US border from Mexico could be highly significant. Once the position
is static it could be possible to look at the possiblity of certain
areas being included in a quarantine set up of some kind.

Being commercial and migratory myself, albeit in a country with no AHB
risk, I can sympathise with migratory beekeeprs and the problems they
could encounter if cut off from either their honey crops or traditional
wintering areas, and even more so with the problems that could be
encountered administering the pollination of the almonds.

It is quite a complex issue.

--
Murray McGregor