Probability of AHB depends on geographic area
A couple of recent studies have indicated that in some areas AHB do not seem to have as big of an advantage over the EHB. I quote from Feral honey bees in pine forest landscapes of East Texas (Coulson, etal 2005):
"The honey bee mitotype diversity we observed in
pineywoods ecoregion mirrors that reported by Pinto
et al. (2004) in the adjacent coastal prairie ecoregion
of TX. However, the environmental conditions for
these two ecoregions are quite different. The coastal
prairie provides ideal habitat for honey bees: cavity
sites are plentiful in live oak mottes and in the
deciduous trees that border stream corridors, high
diversity of flowering plant species provides ample
nectar and pollen, and water sources are reliable and
widespread (Baum, 2003; Baum et al., 2004). In a
representative landscape of the coastal prairie ecoregion,
Baum (2003) reported a density of 12.5 colonies/
km2, the highest ever observed for feral honey
bees. By contrast the pineywoods ecoregion is
depauparate of essential resources and in this
environment the adaptive attributes of A. m. scutellata,
which favor colonization of new habitats, could lead to
the displacement of European mitotypes. However, we
found that in this conifer-dominated forest environment,
sparse in honey bee food and habitat resources,
all the mitotype diversity that could be present, based
on previous introductions, was represented.
The conclusions that follow from this part of the
investigation of feral honey bee races are: (i) honey
bees are a ubiquitous component of the pine forest
landscape in east Texas, (ii) mitotype diversity persists
in the presence of immigration of A. m. scutellata, and
(iii) A. m. scutellata is an added element of the
mitotype diversity in the landscape." (bold added for emphasis)
They claim their study mirrors what was found previously in a study done of the Texas coastal prairie by Pinto etal. The particulars of the studies seem to support that AHB represent about 40% of the feral population and the combination of Eastern European and Western European honey bees are competing well with them in these areas. As such AHB's seem to be adding to the mitotype diversity of these areas instead of replacing it as they have done in other areas further west.
I think it would be prudent for anyone who keeps bees in AHB territory to seek out this type of information. I would especially want to know it before making any blanket statements about a swarm such as "probably AHB". Knowing this information helps make a more informed "guess" about their possible genetics. Particularly in my area if I were basing it on the fact that the swarm was low to the ground. I have hived several swarms this year from just such "low to the ground" circumstances and in both cases when I later inspected the hives, the queens were large and yellow and obviously of mostly Italian genetics, but both had a large chip in a wing that prevented them from flying very high. Neither has shown any AHB characteristics what so ever. In my experience, for the most part, the "low to the ground" thing is not an accurate swarm assessment characteristic. I look mostly at swarm size and timing. For established colonies, I pay close attention to defensiveness and cavity characteristics for a clue (here low or in the ground can be very telling). In the end the only real way to know is to send some bees in for analysis. The few that I have sent in have tested EHB. So far 100% of my attempts at re-queening the hotter colonies I have come across with domestic stock have been successful, so at this point I am dubious as to the degree of africanization in my immediate area since I have not experienced the extreme difficulties that have been documented in attempting to re-queen a highly africanized colony. I have had much more difficulty re-queening Russians (even with Russian queens) than any of my ferals (this includes ferals from counties that have been considered africanized since the early 90's). Of course it could also mean that I have been lucky and not yet come across an AHB swarm or colony in the numerous swarm retrievals and colony removals I have done over the last two years, but if the 40% AHB feral population number from the study is to be believed, that does not seem too likely.
I can't stress it enough though that my experience may not be applicable to folks in other areas. Hopefully there are studies that have been done or are now being done that can provide this type of information to those of you who reside in those areas now actively experiencing the "AHB migration phenomenon".
"The UNKNOWN, huh? That would be SNORBERT ZANGOX over in Waycross."