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and no bees from absconding colonies added to defensive behavior and it takes some of the fun out of beekeeping and our historical reference point using manageable EHB as we know them.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.