Bob wrote:

> Interesting hypothesis but I need to remind all that other than a very few people. AHB has had little actual research. Many researchers I have spoken with say they want no part of digging though hives of AHB counting mites & brood.

I beg to differ. It has been studied for decades, in Brazil, South
Africa, Central America, even in the USA. Ten years ago, Dave de Jong
wrote "Africanized honey bees in Brazil, forty years of adaptation and
success" (Bee World 77 (2): 67-70).

> Some researchers I have spoken with say some hybrid crosses of African genetics and European genetics are poor survivors. In my opinion hybrids can perform all across the scale. If speaking of pure "scuts' in Africa then much of what Peter has posted might be true but when using AHB ( meaning hybrid cross) I wonder.

quote:
> Initially, it was assumed that African and European bees would interbreed, giving rise to the "Africanized honey bee" of Latin America. However, although substantial hybridization occurs when African bees invade areas with European populations, over time European characteristics tend to be lost. ... the hybrid-swarm concept was seriously challenged when mtDNA polymorphisms revealed that over 97% of feral colonies from Brazil, Venezuela, Honduras, and Mexico possessed African mtDNA haplotypes; east European mitotypes were virtually absent. -- from THE AFRICAN HONEY BEE: Factors Contributing
to a Successful Biological Invasion, by Stanley Scott Schneider, et al.

>The Africanized honeybee (AHB) has a unique tolerance to V.
destructor that is not present in the A. mellifera European honeybee.
> Until a researcher tells us *exactly* what that might be causing a *unique tolerance* simply a hypothesis in my *opinion*.

A hypothesis is an explanation for observed data, and it can never be
"exact", The data show African bees surviving, where European bees
don't. This is not a hypothesis, but an observed fact. The paper I
cited attempts to *explain* why this is true.

>12,000 mites are needed to kill an AHB colony.
> So at 11,999 mites the hive can survive. Some researchers would get a chuckle here.

No they wouldn't. They would wonder why you don't get this is just an estimate.

I don't see how you can dismiss the work of people like Stephen J.
Martin and Luis M. Medina. Luis did his PhD on this subject and he
lived in the Yucatan. His work showed:

> mite populations in AHB colonies stabilize at 1000–3000 mites per colony, allowing colonies to survive indefinitely (L.M. Medina, PhD Thesis, University of Sheffield, 2003)


Back in 1999 work was published in Apidologie on this topic. See:

Guzma´n-Novoa, E. et al. (1999) Susceptibility of European and
Africanized honey bees (Apis mellifera) to Varroa destructor in
Mexico. Apidologie 30, 173–182

-- 
Peter L. Borst

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