Order: Hymenoptera
Family: Apidae
Genus & Species: Apis mellifera scutellata
APPEARANCE
The Africanized honey bee (AHB), more popularly known as the "killer"
bee, has the general appearance of the more temperamental European honey
bee (EHB) Apis mellifera. However, they are slightly smaller, but only
microscopic measurements in a laboratory would be able to distinguish
between the two. They are robust, 3/4 of an inch in length, and are covered
in fuzz. They are brownish in colour with black stripes that aren't as distinct
as those on wasps or hornets. They have four clear wings that are attached
to the thorax, which is the middle section of the body. The six legs are also
attached to the bottom of the thorax. The abdomen is larger than the thorax
and ends in the stinger, and the head is smaller than both of the sections.
The two compound eyes are large and bulbous and allow the AHB to see
ultraviolet rays, enabling them to fly at night. The queens are the largest
bees in the social structure, followed by the drones and then the workers.
AHB and EHB may be similar in appearance, but not in behaviour. AHB
will attack when unprovoked, and, although their venom is not quite as
potent as that of the EHB, can kill grown humans because they respond in
larger numbers and will pursue for longer distances. One bee can produce
0.1 mg of venom, the same as that of the EHB. Another major difference
between the two is that EHB produce more honey.
HABITAT
The AHB was first hybridized in Piracicaba, Brazil, and began to spread
through Central and South America. From there they moved into Mexico
and the US. Today they are found in 110 counties in Texas, 14 counties in
Arizona, 7 counties in New Mexico, 1 county in Nevada, and 3 counties in
California. Scientists believe they will continue to spread throughout the
southern US.
AHB are less selective than EHB and can be found in many manmade
objects, including holes or cracks in buildings; under motor homes; in
drainage pipes; flower pots; tires; sheds; woodpiles; playground equipment;
hunting blinds; trash cans; and picnic tables. They can also be found in tree
hollows, woodpiles, rock piles and rotted logs.
AHB live in complicated social structures known as colonies. When a colony
swarms to a new site, they nest, and eventually the original queen will leave
with half the colony to swarm to another nesting site. The remaining bees
then rear a new queen. There are three positions in the bee hierarchy: the
queens, which are fertile females; the workers, which are all infertile females;
and the drones, which are all males and do nothing but breed with the
queens.
FOOD
AHB feed mainly on nectar and pollen from flowers, the nectar providing
sugar and the pollen protein. They also produce honey from the nectar, a
more concentrated, chemically different sweet in which the bees also feed.
Unlike the EHB, they can survive on sparse supplies of food. The worker
larvae are fed either nectar or honey and pollen as well as a secretion from
young workers known as royal jelly for 6 days, after which they leave the
larval stage. The drones are fed the same for 8 days, and the queens are fed
only royal jelly until they are fully grown.
ENEMIES
The main enemy of the AHB is the EHB in that they must compete for food
and nesting areas. They are also eaten by birds, dragonflies, and other
insects.
BREEDING
When the queens are 1 week old, they seek a mate. When a drone mates with
the queen, its genitals become stuck in the queen's body and are ripped off
when they separate, killing the drone instantly. The queen stores the sperm
in her body and fertilizes the eggs as she lays them. Eggs that are fertilized
become females, and eggs that are not fertilized become males.
KILLER BEES
AHB are widely known as the killer bees, and although this may be a slight
exaggeration as they don't fly around looking for victims, they are called
that for a reason. They are highly aggressive and will attack any living thing
that comes within 50 ft of their nest, or any power equipment that comes
within 100 ft. They will pursue a person for 1/4 mile, allowing time for many
hundreds of bees to sting. When they sting, both the stinger and the venom
sack are ripped from the bee's body, killing it instantly. The venom enters
the bloodstream, but is so small in amount only repeated stings will do
much harm. When the stinger is ripped out, high concentrations of a
pheromone known as iso-pentyl acetate are deposited. This acts like a
beacon for other bees and communicates to them to sting. More bees sting:
more pheromone is released. More pheromone is released: more bees sting.
Although they have accounted for only 7 human fatalities in the US, 175
fatalities have been reported in Mexico alone since 1985. This does not
include livestock fatalities, of which there are many.
HISTORY
AHB have a fascinating history. In South America, honey was becoming an
important industry, and so EHB were imported on to farms. However, their
production was not satisfactory, so they looked for other species. In 1956,
geneticist Warwick Kerr was sent by the Brazilian government to Africa to
collect African honey bee queens. He brought back 63 queens, but only 48
survived. Kerr began doing breeding experiments with them, and, by
interbreeding the queens with EHB drones via artificial insemination, the
AHB was born. 29 were born in all. They were placed in a box with queen
excluders that allowed only the smaller workers to fly out so that they would
not reproduce in the wild, and honey was soon made. In 1957, a local
beekeeper noticed the excluders and removed them, trying to be helpful as it
wasn't the season for excluders to be used. 26 AHB queens escaped and
began to rapidly reproduce in the wild. Warwick Kerr was not worried and
assumed that they would mate with other EHB bees and eventually lose their
African honey bee side. However, they did not, and reports of feral bees
attacking livestock began to pour in. In May of 1991, Jesus Diaz became the
first bee sting victim of these "new" bees. He suffered 18 stings. The first
death occurred on July 15, 1993, when Lino Lopez, 82, was stung 40 times
while attempting to remove a colony from a building's wall. Since then,
many more cases have been reported as they spread throughout the US.
RELATIVES
The AHB is considered a subspecies of the EHB and is a hybrid of both it
and the African honey bee, from which it receives its temperament.
RESOURCES CITED
1. Funk & Wagnall's Wildlife Encyclopedia, BPC Pub Ltd, USA, 1974, USA.
"Honey Bee" pg 1055-1058, vol 9.
2. Encarta ‘98 "Africanized Honey Bee" 1993-1997, Microsoft Co.
3. agnews.tamu.edu/bees/
4. www.azpest.com/bee.htm
5. cnas.ucr.edu/~ento/CAAMB/ahb-facts.html
6. ag.arizona.edu/pubs/insects/ahb/infl5.html
7. www.crl.com/~rfleming/ahb.html
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