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One of the most asked questions
about Africanized Honey Bees AHBs since they were released in 1957 has been
how far they will spread into the United States. Since 1990, they have reached
five states--Texas, Arizona, New Mexico, southern California and Nevada--as
well as Puerto Rico and the U.S. Virgin Islands. It was originally thought
there would be regions of pure European, pure African and a region of hybrids.
The genetic and biological differences between European Honey Bees EHB and AHB
have surprised many.
Africanized bees came from an
environment where swarming and absconding were necessary to survive. The AHB
is four to five times more likely to swarm every year or just pick up and
leave when stressed. They will settle anywhere and everywhere. The EHB looks
for larger elevated cavities, where the AHB does not even need a cavity. The
AHB swarms are easier to locate and gather, but just wait! While swarming AHB
are as docile as the friendlier EHB, as soon as they have brood and stores to
protect, they quickly become defensive. That is why collecting swarms is
discouraged. The calm swarm quickly becomes a liability convincing all the
neighbors and news crews that bees are evil.
AHB are not a “temperate” honey
bee and as such are not genetically programmed to prepare for winter by
storing lots of honey. As such they turn most all resources coming in into
more bees thus more swarming. When things get tough they “abscond” meaning the
whole colony gets up and leaves. This is a trait that allows them to survive
pest, parasites and diseases. For instance when Varroa levels reach a negative
tipping point the whole AHB colony leaves (absconds) leaving behind most of
the Varroa. Many people think this is resistance and it is a basic kind of
survival resistance but beekeepers need honey bees to stay in the hive in
order for them to be managed. No bees from constant swarming and no bees from
absconding colonies added to defensive behavior and it takes some of the fun
out of beekeeping and our historical reference point using manageable EHB as
we know them. FDAS and IFAS want to protect you by the use of BMP’s. Being
able to operate under the umbrella of the State against possible law suits for
zoning or ordinance issues was why the Honey Bee Technical Council developed
BMPs.
Africanized bees also usurp a
weak or queenless hive. The mechanism or ability to quickly and accurately
sense when a hive is ripe for taking is not clearly understood yet. The
beekeeper can prevent or reduce the risk of usurpation by requeening with a
marked EHB queen and maintaining healthy hives. Reduced entrances help the
hive to defend itself too.
The most probable encounter
with Africanized bees occurs when a virgin queen mates. Africanized bees
produce more drones in the mating seasons. More importantly EHB queens use
African semen 90% of the time in a study by
DeGrandi-Hoffman. The queens were artificially inseminated with 50-50
EHB AHB semen. You might know the queen can elect to fertilize an egg or not,
but now they select “the daddy.” ARS entomologists believe this is the
strongest factor of AHB replacing EHB in a region. The solution is in the
Florida BMP, use a mated marked EHB queen and replace her regularly.
If you know anything of queens
you know the first one out of the cell kills all her rivals. The AHB queen
emerges a day before the EHB so it is a short contest. AHB queens are also
more successful fighters. Workers perform more
bouts of vibration-generating body movements on African queens before they
emerge and during fighting, which may give the queens some sort of survival
advantage.
Some African traits are genetically dominant, such as queen behavior,
defensiveness, and some aspects of foraging behavior. This means hybrid bees
express more pure African traits. The only god trait apparently is resistance
to Varroa mites. AHB swarm more, abscond more, do not produce as much honey,
and are much harder to work by the beekeeper. Your Bee Inspector can help you
use BMPs to keep your bees in your hive, calm and productive.
You might wonder why Africanized
bees have not spread farther in so many years. ARS entomologist José D. Villa
at the ARS
Honey Bee Breeding, Genetics and Physiology
Research Unit in Baton Rouge, La., has found a correlation between
rainfall of more than 55 inches, distributed evenly throughout the year, and
an almost complete barrier to AHB spread. There is no idea why or how that
works, but pray for rain and requeen regularly with marked EHB queens.
Spread of
Scutellata in Africa
Mean Annual
Rainfall in Africa
Spread of Scutellata
in Florida
Florida average
rainfall
Africanized Honey Bee Fact Sheet ~ pdf
Africanized
Honey Bee Activity Sheet ~ (for kids)
The Africanized Honey Bee Brochure ~ pdf
The Africanized Honey Bee Brochure (spanish) ~ pdf
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