IMPORTANT DIFFERENCES BETWEEN AFRICANIZED AND EUROPEAN HONEY BEES

Africanized and European honey bees are members of the same species, Apis mellifera. They represent populations that have evolved under different environmental conditions. The same basic behavior, biochemistry, and structure are expressed by all members of the species. However, there are differences in their range, size, or frequency of expression of some characteristics. The differences that do exist have led to our concerns about thespread of the AHB into the United States; however, they have allowed us to distinguish them from European honey bees.

Defensive Behavior

The single characteristic of Africanized honey bees (AHB)receiving the most public attention is their excessive level of colony defense. All honey bees respond to perceived threats tothe nest; however, AHB do so more readily and more vigorously than European honey bees (EHB). In studies with both types of colonies, the AHB responded to cues of disturbance, alarm pheromone, and moving targets much faster than the EHB. In addition, three to four times as many AHB worker bees reacted and left eight to ten times as many stings in 30 seconds in suedetest targets. A greater number of AHB will pursue intruders for a greater distance than EHB. Research has confirmed that there is a great deal of behavioral variation in both populations between colonies and from day to day. It is important to recognize that AHB colonies are unpredictable and have a greater potential for excessive stinging. Africanized honey bees have killed people and domestic animals. In Mexico over 1,000 stingings, which include 58 human deaths, have been reported between September 1986, and September1991. When an apiary is disturbed by a beekeeper or other intruder, AHB colonies remain aroused and defensive much longer. It may take a disturbed AHB apiary as long as a week to return to a quiet state.

The Technical Working Group of the USDA is recommending that beekeepers not attempt to manage Africanized colonies. They should requeen, move, or destroy such colonies. Even a few colonies of defensive bees in an apiary may cause problems. Weather, season, and food availability can affect the demeanor of any honey bee colony. Consequently, predicting times when a colony may become defensive is difficult. Assuredly, unprepared beekeepers are at risk of being seriously stung. The honey production potential of the Africanized honey bees is a characteristic that is often misunderstood. This trait is highly dependent on the quality and quantity of nectar available for collection by foraging bees. The differences in behavior that are seen in AHB are ones that make them more effective survivors in a tropical environment where nectar flows are often scattered, are of poor quality nectar and are irregular. It is rain that stimulates blooming, not the season. Those same characteristics make them unsuited as effective honey producers in temperate climates where the pattern is a seasonal one, nectar flows are intense, and there is a long period with no bloom(winter).

For the beekeeper, this means that for most areas with economically important nectar flows, the European varieties will out produce Africanized honey bees.

.Colony Reproduction

One survival adaptation of Africanized honey bees is to multiply quickly and then to swarm. The Africanized honey bee has the propensity to swarm more often than the European honeybee. Africanized honey bees have a shorter development time,emerging as adults approximately one day earlier. Another difference is in the brood pattern. The AHB brood is often in a wide pattern filling an entire frame. Beekeepers listed the characteristic full frames of brood as being the most significant visible difference between EHB and Africanized honey bees. All this brood may be maintained with little stored honey and pollen. As soon as nectar and pollen are brought into the hive, they are used to feed young larvae.

Body Size and Color

The expression of body size is the difference that is used for the official identification of the Africanized honey bees. The AHB is smaller than the EHB. A method called USDA-ID uses measurements of wings, wing angles, legs, and wax mirrors to predict the probability that a sample of ten bees from a colony is AHB or EHB. The procedure requires dissection of the bees and measurement with the aid of a computer. Body color is a very unreliable characteristic for identification of AHB. Although they tend to be dark and distinctively striped, there is considerable variation within theAHB population. Also, some European honey bees may show similar coloration. Another size measurement that has been used to make preliminary identifications in the field is the length of tencells of honey comb. This distance in EHB is usually greater than 5.0 cm and in AHB less than 4.9 cm. Several measurements must be made in areas of naturally drawn comb with no distortions.

Other Observable Differences

Africanized bees on the comb are nervous, or "runny." Often they will fly off a frame when it is handled, or may hang from the bottom edge in festoons. Since the queen frequently runs on the comb, she can be difficult to find within the hive. Additionally, mated and laying AHB queens have been observedto fly away from a colony as it is being examined. It is notunusual to have to remove all the frames from a hive to search for the queen. The AHB may also "parade" around the empty beehive in great swirls. Africanized honey bee colonies often show heavy propolizing,especially around the entrance. Their behavior in reducing the entrance area with large sheets of propolis may be a defense against ants or other predators. An invalid identification attribute is the quick, jerky flight attributed to the AHB. It has been incorrectly reported that only returning Africanized honey bee workers seem to fly directly into the entrance without landing on the landing board. European honey bees may also act this way during good nectar flows.