The Africanized Honey

Although the African honey bee (above left) is slightly smaller than its European counterpart (right), the two belong to the same species, and only a highly skilled expert using sophisticated techniques can tell them apart. Africanired colonies are easily aroused, a trait that has given them a reputation as “killer bees.” (Photos by E.S. Ross) The Af ricanized honey bee: ahead of schedule Norman E. Gary 13 Howell V. Daly 0 Sarah Locke 0 Margaret Race The bee’s early arrival added urgency to efforts to devise effective controls Theaccidental discovery in June 1985 struction of any wild honey bee colonies Across this range, the races differ little in of a wild colony of Africanized honey bees found in the area. Agency officials and appearance or structure, but do differ sig- in Lost Hills, near Bakersfield, was un- scientists are cautiously optimistic that nificantly in behavior. Over the years, the welcome news for California apiculturists their actions, combined with genetic dilu- relatively gentle European races were and growers. The bee’s appearance in tion, will prevent the further spread and taken to other continents for use by bee- California was not a complete surprise, premature establishment of the African- keepers. The honey bees in both North and but it was not expected to arrive until ized bee in the continental United States. South America originated from European sometime in the 1990s after gradual mi- At the time this article was written, five sources, with the Italian race, Apis melli- gration and spread from its present north- commercial and three wild colonies of fera ligustica, the most favored by com- ernmost location in Honduras, Central Africanized bees had been found and de- mercial beekeepers. America. The bee’s early arrival was stroyed, but additional finds were expect- A race of African bees, Apis mellifera probably caused by the unintentional im- ed. All finds to date are of mixed parent- scutellata, was introduced into Brazil in portation of a wild colony inside drilling age, indicating that the common 1956 in an effort to breed a bee that would equipment shipped from South America European bee in California is interbreed- produce more honey in the tropics. Euro- to the oil fields in Kern County, or from a ing with the introduced Africanized bee, pean bees are adapted to temperate cli- truckload of imported cargo. and suggesting that genetic dilution is oc- mates and do not perform well in tropical As additional colonies were found dur- curring. and subtropical climates, especially in the ing the summer, California’s Department lowlands. As part of a breeding program of Food and Agriculture intensified its History to eliminate or minimize the African bee’s monitoring and eradication efforts, im- The honey bee, Apis mellifera, ranges undesirable characteristics while retain- posed a holding action on the movement from northern Europe to the southern tip ing its honey-producing traits, Brazilian of commercial hives, and ordered the de- of Africa, and eastward into western Asia. researchers brought 47 queens from Afri- 4 CALIFORNIA AGRICULTURE, NOVEMBER-DECEMBER 1985 ca to Rio Claro in the state of SoPaulo, Brazil. The bees were introduced into colonies equipped with double queen excluders covering the entrances to prevent their escape. In 1957, a visiting beekeep- er, not understanding the strict precau- tions against the escape of queens and drones, removed the queen excluders from 35 hives when he noticed an accu- mulation of pollen at the entrances. Be- fore his action was discovered, 26 colonies had swarmed or absconded. After several years, it became appar- ent that the strain of African bees was not being diluted by the established European bee population but that European colonies were becoming Africanized. The African bee apparently hybridized to a limited degree with European stock, leading to a strain that genetically is still almost iden- tical to the original African bee but is re- ferred to as the Africanized or “killer” bee. Various Brazilian attempts between 1963 and 1972 to dilute the Africanized bees by requeening the most aggressive colonies with Italian bees had only limited success. Africanized bees quickly supplanted European stock, expanding their range 200 to 300 miles a year from the original epicenter in Brazil, and now have reached Honduras. Studies in Venezuela, Colom- bia, and Central America found the bee has retained virtually all of its African The combs distinguish the Africanized from the European bee; Africanired worker Cells characteristics as it has spread. in natural comb (bottom) are smaller than the comb cells of European honey bees. The bees are expected to arrive in Tex- Africanized bees develop faster and live shorter lives than European bees. Some as around 1988-90 and to become estab- apiculturists believe the Africanired bee is a better honey producer. lished from Florida to California in areas with adequate nectar, pollen, and nest Africanized bees reportedly have a longer rather than walking in as European bees sites, and suitable winter conditions. life expectancy than those of European do. When compared with European honey bees, suggesting that they may be more bees, African bees in Africa foraged at Biology/natural history successful at replacing queens than are lower temperatures and light intensities, No single structure distinguishes Afri- European colonies. foraged in the rain, and foraged earlier can or Africanized bees from European Africanized bees nest in cavities found and later during the day. bees. Differences are a matter of degree in the ground, in termite mounds, under In some areas, Africanized bees reput- and not of kind. buildings, in barrels, and in old cars. edly produce more honey per colony than Africanized worker and queen bees on Sometimes they even construct combs in European bees, although there is conflict- average are slightly smaller than workers open exposed nests. They appear to prefer ing information on the subject. Commer- and queens of the European races. Afri- somewhat larger cavities for their nests cial honey production in northern Brazil canized worker cells in natural comb are than European bees do, even though they dropped dramatically after many bee- also smaller in average diameter. Color is may only partially fill them with comb. keepers were forced out of business by the highly variable, but most Africanized European honey bees select smaller cav- bees’ temperament, but efforts to im- workers have yellow abdominal bands. ities that are large enough to store winter prove beekeeping techniques have Development time from egg to adult is food reserves. Both races maintain simi- changed this. shorter for Africanized than European lar brood nest temperatures. The best known characteristic of Afri- workers (18 to 20 days versus 21 days). Originally it was assumed that Afri- canized bees is their extreme defensive- During the tropical dry season when flo- canized bees were unable to overwinter in ness, usually misinterpreted as aggres- ral sources are abundant and colonies be- cold climates, but recent studies in Argen- siveness. Colonies are extremely sensitive gin a rapid population increase before tina, as yet unpublished, indicate that they to disturbances, such as vibration, foreign swarming, Africanized workers live 12 to may be able to overwinter much farther odors, and movements, and the bees re- 18 days compared with 32 to 35 days for north in the United States than was pre- spond faster, in much greater numbers, European worker bees. viously supposed. and with more stinging than European Colony growth of Africanized bees is Africanized bees are more excitable bees. When disturbed, they follow and per- reported to be rapid, and the annual egg- and active than European bees, flying in sistently sting animals and people hun- laying rate is approximately double that quicker and more erratic patterns and of- dreds of yards from their colony. Recov- of European bees. Individual colonies of ten flying directly into the hive entrance ery time after disturbance is about 30 CALIFORNIA AGRICULTURE, NOVEMBER-DECEMBER 1985 5 Africanired bees show little discriminationin where they build their nests: in the ground, in termite mounds, under buildings, in exposed areas, even in old cars. Norman Gary, UC bee researcher, checks the nest of the first Africanired bee colony discovered in the United States, near Lost Hills, California, in June 1985. The well-established nest contained approximately 20 combs. minutes for Africanized bees compared ter. Absconding differs from reproductive with 3 minutes for European bees. Re- swarming in that the colony produces no Identification searchers concluded that Africanized bees new queens, and all the workers and There are two levels of identification are up to ten times more active in sting- drones leave the nest with the mated of Africanized honey bees, one for detect- ing than European bees. queen. European colonies rarely abscond; ing their presence, and the other for de- Individual Africanized bee stings are Africanized bees do so regularly. Ab- tecting varying degrees of hybridization no different from European stings. No sconding rates for honey bees in tropical between Africanized and European bees, significant chemical differences between Africa are 15 to 30 percent a year, but can once they coexist. Because African and venoms of Africanized and European bees be up to 100 percent in some areas. European honey bees are two races of the are known. The difference in stinging epi- In Brazil, wild Africanized bees are same species, the differences between sodes is due to the sheer number of sting- abundant. In one study, an average of 107 them and their hybrids are quantitative ing Africanized bees. A substantial num- colonies per square kilometer were found rather than qualitative. The problem of ber of cases have been reported in which in a savanna region.

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