FCAT Express

Natural Born Killers

By Kurt Loft
of The Tampa Tribune

Scientists hope to take the sting out of those dreaded killer bees. A team of researchers has isolated a gene responsible for the aggressive behavior of Africanized honey bees, which have terrorized people and animals in their slow migration into the southern United States.

Scientists located DNA markers on the chromosomes of the mean bees and compared the genes with those of nonaggressive species. Their research may lead to the origins of a trait that could help “predict the probability of queen bees having the African version of stinging genes so it will be easier for breeders to avoid using them,” says Robert E. Page, an entomologist at the University of California at Davis.

Borrowing techniques from crop genetics, the team ultimately hopes to turn killers into kinder, gentler insects. Bees are essential to honey production, and a third of the food grown in the United States comes from plants pollinated by honey bees. The U.S. Department of Agriculture in 1993 committed nearly $1.8 million to Africanized bee research, and the current study was funded by the National Institutes of Health.

Killer bees are known to swarm in larger numbers than typical honey bees, releasing a pheromone odor that stimulates the rest of the colony. The odor comes from the stinger itself, which dislodges from the insect’s abdomen upon stinging.

Swarms of killer bees are 20 times more likely to sting than normal honey bees, and leave eight times as many stingers in a victim in the first 30 seconds, researchers say.

The first fatality attributed to killer bees in this country happened in July 1993, when 82-year-old Lino Lopez was stung at his ranch near Rio Grande City, Texas. In October of that year, a swarm of 30,000 killer bees terrorized a neighborhood in Peoria, Arizona, for nine hours, with three people injured from stings and three dogs killed. Authorities in Mexico, where killer bees concentrate, have reported roughly 20 deaths a year since 1986, mostly in areas with poor medical care.

Killer bees were imported to Brazil from Africa more than 40 years ago. The idea was to crossbreed African and South American species to produce a gentle bee with high honey production. African bee colonies can produce five times as much honey as their South American cousins. As a result, Brazil rose from 27th to fourth in the world’s honey production, according to the U.S. Department of Agriculture.

Unfortunately, a Brazilian scientist accidentally released some of the captive insects from Africa. The mean bees soon mated with indigenous colonies and their aggressive behavior spread.

They moved into Central America and were documented in Mexico in 1988. Within three years, scientists think, most wild bees in Mexico contained DNA from the African species, and killers were found in California, Texas, New Mexico and Arizona.

Bee stings aren’t so much “aggressive” behavior as defensive says Greg Hunt, an entomologist at Purdue University in Indiana. “Different insects use various methods to protect themselves from predators. Bee stings are a response to predation by mammals – bee venom is specialized for causing pain.”