Battle of the Bees
African honeybees (A.m.Scutellata) may be tough and temperamental, but they’re no match for the relatively mild-mannered Cape honeybee (A.m. Capensis).
Sometimes the nicer bee wins.
In a battle of bees in South Africa, the clever and unassuming Cape honeybee overcomes, through a surprising subterfuge, its more ferocious cousins, the African honeybees. The African honeybees are the original 'killer bees,' ancestors of the swarming, aggressive bees now marauding through the Americas.
First, the Cape honeybees dispatch small swarms of female workers to sneak into African 'killer bee' hives.
There they lay eggs in the hives of their unwitting hosts. The infiltrating Cape larvae then manipulate the killer bee workers into giving them better food than what is fed to their host’s own brood. This gourmet-quality food contains less sugar filler and more nutrients than regular honeybee food. It’s more like what the queen bee is served.
Writing in Thursday’s issue of the journal Nature, researchers led by Madeleine Beekman, a research associate at Sheffield University’s Laboratory of Apiculture and Social Insects in England, offer a theory about how Cape larvae are able to receive the royal grub:
'We think that this is caused by the [Cape honeybee] brood having a different smell, meaning different pheromones,' Beekman says. 'In some way this results in the nurse bees feeding this brood more food and food of different composition.'
Beekman and her colleagues analyzed the interaction between Cape and European honeybees, but she says her study can apply to how the Cape bees raid African killer bee colonies, too.
Pampered and well fed, many of the Cape larvae develop into pseudoqueens, possessing some of the characteristics typical of queen bees, such as greater body weight. These pseudoqueens are the key to the overthrow.
Explains Robert Danka, research entomologist at the U.S. Department of Agriculture’s Honey Bee Breeding, Genetics and Physiology Laboratory in Baton Rouge, La.:
'Pseudoqueens don’t work like workers and they aren’t normally as reproductive as regular queens. The colony becomes dysfunctional and you wind up with a bunch of weird misfits.'
In the ensuing chaos, the killer bees reject their own ruling queen. When faced with this dire situation, killer bee workers usually are able to rear an 'emergency queen.' But the presence of egg-laying Cape workers prevents them from doing this. Eventually the host colony either dies out, or the egg-laying workers are usurped by a Cape bee queen.
Killer Bees in the USA
Still, the killer bees have spread farther around the world than their Cape invaders. In 1956, Brazilian scientists brought the aggressive African bees to South America in a botched experiment to create a better honeybee. Some of the African bees escaped quarantine and bred with local bees, creating the hybrid species now commonly called 'killer bees.' Now they’ve spread to several different countries, including America, overwhelming other species of honeybees.
The first swarm was detected in the United States in 1990 in the border town of Hidalgo, Texas. At present, killer bees are firmly established throughout much of Texas, New Mexico, Arizona, Nevada and California.
The Africanized killer bees, like their original African honeybee ancestors, are deadly because they are very short-tempered and can be vicious when disturbed. While their venom is no more potent than that of native bees, killer bees may remain agitated for an entire day, attacking people and animals up to one quarter of a mile from their hive.
The attacks can be deadly. One Texas man died after he was stung more than 40 times while he trying to remove a colony from a wall on his ranch.
The Cape honey bee a solution?
Given their ability to destroy killer bees, could the Cape honeybee help us to curb the attack of the killer bees in the United States?
Here, the honeybee of choice is the European honeybee, which doesn’t possess the same talent for guerilla warfare.
Unfortunately, no, according to Danka.
'An introduction of Cape bees to alleviate problems with Africanized bees,' he says, 'would be exactly wrong for beekeeping according to most beekeepers who have experience with both bee types in Africa.'
Danka explains Cape bees would invade not only the colonies of killer bees, but also virtually all bee colonies, causing them to become nonproductive or to die. Cape bee genes could mix with those of our honeybees, ruining hundreds of years of selective breeding.
'In the end, it may be summed up that, at least for beekeepers, the problems posed by Africanized bees are less than those posed by Cape bees.'
Sometimes, nicer doesn’t mean better.