The African Honey Bee - UNC Charlotte Pagestion, African honey bee genetics and biology. Deborah Smith received her PhD in Neurobiology and Behavior from Cornell University and post-doc-toral

1April 2006 BEE CULTURE

The African Honey BeeThe African Honey BeeA Case Study Of A Biological Invasion

Stan Schneider, Gloria DeGrandi-Hoffman, Deborah Smith, David Tarpy

One of the most amazing bio-logical phenomena that has oc-curred in our life time is the intro-duction and spread of the Africanhoney bee (AHB) in the westernhemisphere. Within 50 years of itsinitial introduction into Brazil, theAHB has colonized much of the NewWorld, giving rise to one of the mostrapid and spectacular biological in-vasions humans have ever wit-nessed. A remarkable feature of theAHB is its ability to displace resi-dent European honey bees (EHB).As the AHB migrated northwardfrom Brazil, it largely or entirely re-placed feral European honey beesin almost every area where it be-came established, often with dra-matic consequences for apiculture,agriculture, and public safety. In-deed, a project that began 50 yearsago as a means to improve honeyproduction in Brazil ultimatelychanged beekeeping in 17 countriesover two continents. The African beearrived in the U.S. in 1990. It is nowpermanently established through-out the southwestern states and

parts of California, where it is dis-placing feral EHB populations andcreating public safety concerns inmany regions. Recent reports of theAHB from Louisiana and Floridaraise the possibility that the south-eastern states will also be colo-nized by this highly invasive insect.

Learning to control and copewith the African bee (and with themedia attention that invariably fol-lows it) requires knowledge of itsbiology, history, how it interactswith European bees, and the effectsit is likely to have as it spreads inthe U.S. To this end, we present aseries of three articles that discussthe major aspects of the AHB in theAmericas. The first article comparesthe biology and survival strategiesof African and European bees andsummarizes the history of the AHBin the western hemisphere, begin-ning with the initial introductionsinto Brazil. The second article dis-cusses the different factors thatinfluence the AHB’s ability to dis-place European honey bees in thewestern hemisphere. In the finalarticle, we examine the spread andeconomic impacts of the AHB in theU.S. and speculate about its pos-sible future movements.

The Biology of African andEuropean Honey Bees

The honey bee, Apis mellifera, isnative to the Old World and occursnaturally from the southern tip ofAfrica to Russia. Within this enor-mous geographic range, populationshave adapted to different environ-mental conditions giving rise tomore than 20 different subspecies,or races. These races can be dividedinto two main groups, based on thetype of environment they haveevolved to inhabit. Temperate cli-mate races occur in Europe and arecollectively referred to as Europeanhoney bees. The primary factorshaping the survival strategy ofthese races is Winter. To surviveWinter, colonies must amass hugehoney stores, which require that

they occupy large, well insulatedcavities, build large amounts ofcomb, maintain large worker popu-lations and foraging forces, andemphasize nectar over pollen col-lection (Fig. 1).

European honey bees swarmprimarily in the Spring and earlySummer, to provide new colonieswith sufficient time to amass largefood reserves, and typically produceonly 1-3 swarms per year. In addi-tion, European colonies tend to“stay put.” They rarely abandon nest

Figure 1. Unlike European bees, whichmust occupy large, insulated nest cavitiesfor Winter survival, AHB colonies can oc-cupy smaller cavities and are more likelyto build exposed-comb nests.

sites and never migrate to escapeWinter conditions.

In contrast, tropical races ofhoney bees occur in Africa. They donot experience such cold Wintersand can often forage year round.This reduces the benefit of amass-ing large food reserves and allowscolonies to construct smalleramounts of comb and occupysmaller nest cavities. A major sur-

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Stan SchneiderStan SchneiderStan SchneiderStan SchneiderStan Schneider received his PhD in Animal Be-havior from the University of California at Davis andis now at the University of North Carolina at Char-lotte. His main areas of research are honey bee com-munication and the biology and behavior of the Afri-can honey bee.

Gloria DeGrandi-Hoffman Gloria DeGrandi-Hoffman Gloria DeGrandi-Hoffman Gloria DeGrandi-Hoffman Gloria DeGrandi-Hoffman received her PhD fromMichigan State and is now Research Leader at theUSDA Bee Lab in Tucson. Studies include pollina-tion, African honey bee genetics and biology.

Deborah Smith Deborah Smith Deborah Smith Deborah Smith Deborah Smith received her PhD in Neurobiologyand Behavior from Cornell University and post-doc-toral training in molecular biology at the Laboratory forMolecular Systematics at the University of Michigan.She is now at the University of Kansas, studyingmitochondrial DNA analysis, honey bee biogeogra-phy and honey bee population biology.

David David David David David TTTTTarpyarpyarpyarpyarpy received his PhD in Entomology fromthe University of California at Davis and is now theExtension Apiculturist in the Department of Entomol-ogy at North Carolina State University. His researchinterests address the biology and behavior of honeybee queens – using techniques including field ma-nipulations, behavioral observation, instrumental in-semination, and molecular genetics.

BEE CULTURE2 April 2006

vival challenge faced by Africanraces is a high level of predation,which selects for increased sting-ing responses and high rates ofcolony reproduction. African racesare often more defensive than Eu-ropean races (Fig. 2). Also, they typi-cally produce three to four times asmany swarms (3-12 per year) and,because of the prolonged foragingseason, often have several swarm-ing periods throughout the year.High rates of swarming require in-creased brood production. African

bees devote two to four times morecomb space to brood rearing thanEuropean bees and emphasize pol-len over nectar collection to providethe proteins needed for increasedbrood production. Also, AHB work-ers have a shorter development timethan EHB workers (18.5 versus 21days, respectively), which furtherpromotes the rapid build up ofcolony size and frequent swarming.Another challenge facing Africancolonies is the shifting pattern offloral resources that arises from theshifting, and often unpredictablepatterns of rainfall of the Africancontinent. Rather than hoard largeamounts of food to survive dearthperiods, African colonies often mi-grate long distances to follow sea-sonal changes in forage availability.African colonies will also readilyabscond in response to disturbanceand predation. As a result, Africanbees are much more mobile andmore inclined to abandon nest cavi-ties than are European honey bees.

Thus, even though Europeanand African honey bees belong tothe same species, look virtuallyidentical (Fig. 3), and have the samesocial structure, they have empha-sized different aspects of their nest-ing biology, comb usage, foragingbehavior, reproduction and move-ment patterns to adapt to their dif-ferent environments.

The European races of honeybees are the most familiar to us.Their large population sizes, alongwith their emphasis on honey pro-duction, low swarming rates and re-luctance to abscond make themideal for beekeeping and agriculture.Starting in the 1600s or earlier,European honey bees were intro-duced repeatedly into NorthAmerica by the first settlers thatcame from Europe. The bees thrivedand quickly established large wildpopulations throughout the coun-try.

European races were also con-tinually introduced into Central andSouth America. Although somecountries developed sizable bee-keeping industries, European beesdid not thrive in tropical habitats.They required extensive humanmanagement and never establishedlarge feral populations. Some na-

tions therefore began to explore thepossibility of importing African racesof honey bees. Although the in-creased defensiveness, highswarming rates, absconding andmigration behavior of African beeswere recognized as detriments tobeekeeping, it was thought that se-lective breeding could modify theseundesirable traits, resulting in agentle, tropically-adapted bee thatwould improve beekeeping andhoney production in the Neotropics.

The differences in the biology ofAfrican and European bees thatevolved over millennia therefore setthe stage for the AHB invasion, andno one could have foreseen theenormous consequences that wouldarise from the subtle behavioral dif-ferences between these subspeciesof honey bees.

The History of the AHB in theAmericas

The story of African honey beesin the New World begins in Brazil(Fig. 4). From 1954-1955, beekeep-ing agencies, government depart-ments and private beekeeping co-operatives initiated projects in Bra-zil to increase the low honey pro-duction of the European colonieskept by commercial beekeepers. Thebest subspecies to introduce intoBrazil was determined to be A. m.adansonii from southern Africa, apopulation now re-classified as A.m. scutellata. In 1956, Dr. W. E. Kerrtraveled to Africa to select queensof the best stocks. Queens wereselected from Angola, Mozambiqueand Bloemfontein, and Republic ofSouth Africa, but none survived. Sixqueens were collected inTanganyika, of which one survivedintroduction to Brazil. Of 132queens collected from Pretoria,South Africa, 46 survived introduc-tion into Brazil. These few surviv-ing colonies are often viewed as theonly colonies that gave rise to theAfrican population in the NewWorld. However, we now know thatthere were other introductions ofAHB into South America, as well ashuman-assisted distributions ofAHB queens to beekeepers. In com-bination, these colonies and queensformed the nucleus of the Africanpopulation that would eventuallycolonize much of the western hemi-sphere.

Initially, it was thought thatinterbreeding between African andEuropean bees would geneticallydilute the undesirable AHB traits.

Figure 2. The African honey bee race,Apis mellifera scutellata, is well knownfor its high degree of nest defense. Hereare data comparing the number of beescaptured while defending their colony inthe first 30 seconds after a disturbance.About five times more African bees leavethe colony than European bees in thesame time interval. AHB workers also pro-duce more alarm pheromone than EHBworkers, which excites other workers tosting, and further contributes to greatercolony defensiveness.

Figure 3. An AHB worker (left) and EHBworker (right). African and European beeslook virtually identical, although Africanworkers develop faster in the larval stage.AHBs sometimes have a darker color thanEHBs, but color is too variable in bothraces to be used as a reliable identifica-tion mechanism. The two races differ morein how they behave rather than how theylook.

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Although the EHB had never estab-lished wild populations in theNeotropics, many countries main-tained large (sometimes enormous)populations of managed colonies.As the comparatively small Africanpopulation interacted with the muchlarger managed EHB populations, itseemed logical that the AHB wouldbecome less-and-less “African like”as it spread northward. Early in theinvasion process, it was widely be-lieved that there was unrestrictedmating and genetic exchange be-tween the EHB and AHB popula-

tions. As a result, the feral bee inthe Neotropics was given the com-mon name, the Africanized honeybee, because it was thought to be ahybrid that arose largely from Euro-pean queens mating with Africandrones. The population advancingnorthward was considered to be a“hybrid swarm” that consisted pri-marily of swarms escaping frommanaged European apiaries inwhich the queens had mated tosome extent with African drones.

The development of moleculartechniques allowed for increasingly

detailed studies of the genetic struc-ture of the African population. Asthese studies progressed, it becameclear that the hybrid-swarm andgenetic dilution concepts were in-correct. Studies of mitochondrialDNA were particularly important inthis research. Unlike the DNA inthe nucleus of cells, which is in-herited 50/50 from the mother andfather, mitochondrial DNA is inher-ited solely from the mother. Thus,if the feral honey bees in theNeotropics were Africanized (hy-brids of European queens and Afri-

TOOLS OF THE TRADE Deborah Smith

Genetic Genetic Genetic Genetic Genetic TTTTTools Used to Study Honey Beesools Used to Study Honey Beesools Used to Study Honey Beesools Used to Study Honey Beesools Used to Study Honey BeesAllozymesAllozymesAllozymesAllozymesAllozymes are slightly different forms of the same protein, caused

by mutations in the genes that produce them. This technique, the firstused in honey bee genetic studies, is relatively cheap and provideshigh quality information: it is possible to detect whether individuals haveinherited the same form of a protein gene from each parent (in whichcase they are called “homozygotes”), or a different one from eachparent (“heterozygotes”). Unfortunately, honey bees show very littlevariation in allozymes. Just two, called MDH and HK for short, showpronounced differences between African and European honey bees.For more than 20 years, these have been the “work horses” of honeybee population genetic studies. However, proteins are relatively deli-cate molecules, so it is necessary to use fresh or well frozen tissues.This means that samples collected into alcohol and samples in poorcondition cannot be analyzed, and dry ice, liquid nitrogen and -80°Cfreezers are not always easy to come by.

The DNA molecule is tougher than protein, so useable DNA canbe extracted from samples that have been frozen, stored in alcohol, orfreeze dried, making collection of samples much easier, and a variety ofrapid and simple methods to extract DNA from tissues are available.Many genetic techniques detect differences in DNA sequence directly.These techniques reveal much more detail about the genome thanallozymes can, but require specialized, and sometimes expensive, chemi-cals and equipment.

Restriction enzymesRestriction enzymesRestriction enzymesRestriction enzymesRestriction enzymes: Many different restriction enzymes arecommercially available, each recognizing a different sequence of 4, 5or 6 nucleotides in a strand of DNA. A DNA sample is incubated with arestriction enzyme; if the restriction enzyme detects its specific recogni-tion sequence of 4-6 nucleotides, it will bind to the DNA strand and cut itin two at that point. If samples of DNA from two individuals are com-pared, one may possess a recognition sequence (e.g., GAATTC) andthe other may have a different sequence not recognized by the enzyme(e.g., GGATTC). If these samples are incubated with the restrictionenzyme, fragments of different length will be produced: restrictionrestrictionrestrictionrestrictionrestrictionfragment length polymorphisms, fragment length polymorphisms, fragment length polymorphisms, fragment length polymorphisms, fragment length polymorphisms, or RFLPs RFLPs RFLPs RFLPs RFLPs.

RFLPs are used extensively to compare and classify honey beemitochondrial DNAs, which are relatively small. African, west Europeanand east European mitochondrial DNA are each characterized by uniquepatterns of presence or absence of particular restriction enzyme recog-nition sites.

Microsatellites Microsatellites Microsatellites Microsatellites Microsatellites are a form of what is loosely called junk DNA. Amicrosatellite “gene” contains many repeats of short, simple sequences,such as AATAATAAT, or GCGCGC. These repeats are a sort of “tongue-

twister” for the cellular machinery that replicates DNA in the living cell—it is easy to accidentally delete or duplicate copies. Thus, different indi-viduals in a population may have, for example, 90, 100, 101, 102 ormore copies of a short sequence strung end to end. Although they donot code for any product, microsatellites are useful to a population biolo-gist because they are abundant, highly variable, and rapidly evolving,and can be used as markers to distinguish populations or even indi-viduals. A typical animal genome may contain thousands or even mil-lions of microsatellites “genes” scattered around the chromosomes. In apopulation of organisms, there may be dozens or more variants oralleles for each microsatellite “gene,” each consisting of different num-bers of repeats (a microsatellite “gene” is more properly called a locus,or place, on the chromosome, since genes code for a product or func-tion; each copy number variant is a different allele). Unlike allozymes,with only two genes loci that show differences between African andEuropean bees, hundreds of microsatellite loci have been identified inhoney bees, many of which show differences between African andEuropean populations in the type and frequency of alleles. It is expen-sive and time consuming to develop a system to detect microsatellite lociin a new study organism, but once developed they are relatively quickand cheap to use (assuming one has invested in the appropriate labequipment).

DNA sequencingDNA sequencingDNA sequencingDNA sequencingDNA sequencing determines the actual sequence of nucleotidesin a particular gene or other piece of DNA. This provides the mostdetailed information, but within a single species most nucleotides in agene will be the same and differences will be few. It is also too expen-sive and time consuming to carry out on the large numbers of individu-als typically used in population studies. However, a new technique is onthe horizon that will make it possible to screen large numbers of indi-viduals for a polymorphism revealed by sequencing studies.

Single nucleotide polymorphisms, or SNPs.Single nucleotide polymorphisms, or SNPs.Single nucleotide polymorphisms, or SNPs.Single nucleotide polymorphisms, or SNPs.Single nucleotide polymorphisms, or SNPs. The recentlycompleted Honey Bee Genome Project (HBGP, carried out at BaylorCollege of Medicine) sequenced the entire genome of a U.S. “Italian”honey bee. Parts of the genome of the European bee were comparedwith DNA sequences from Africanized honey bees from Texas, andmore than 1500 places were found where the European and Africansequences differed by a single nucleotide – SNPs (pronounced”Snips”).Thus SNPs represent just variable nucleotides, distillated out of the vastvolume of DNA sequence data generated by the HBGP. These mark-ers will provide a valuable set of markers for analysis of the Africanizationprocess, detecting genes associated with desirable traits, and manyother studies.

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can drones), then their cells shouldcontain only European mitochon-drial DNA. However, in the late1980s Dr. Deborah Smith of theUniversity of Kansas and Dr. H.Glenn Hall of the University ofFlorida independently discoveredthat 97% of all colonies sampled inmany regions of Latin America con-tained only African mitochondrialDNA. There was only one possibleexplanation: Rather than expand-ing northward as European-matriline hybrids, the feral honeybees in Central and South Americawere composed almost entirely ofcolonies that arose from Africanqueens. Colonies arising from Eu-ropean queens were virtually ab-sent. Although EHB queens in man-aged colonies were mating with Af-rican drones, European-matriline(Africanized) swarms escaping fromapiaries were clearly not survivingin the wild.

This phenomenon is particularlystriking in areas such as theYucatán, Mexico and southernTexas, where the invading front en-countered huge populations of Eu-ropean colonies. When the AHB ar-rived in Mexico in 1985-86, theYucatán Peninsula supported oneof the highest densities of Euro-pean apiaries in the world. Yet,within 12 years, only about 20% ofthe managed colonies were stillEuropean and today wild European-matriline colonies are virtually non-existent in the area. Recently, Dr.Alice Pinto, working at Texas A&MUniversity, found a similar situa-tion in southern Texas. When theAHB arrived in 1990, southern Texascontained large populations of bothmanaged and feral European honeybee colonies. But, by 2001 only about10% of feral colonies were of Euro-

pean maternity, suggesting thatcolonies arising from AHB queenshad displaced most of the wild Eu-ropean population. Interpreting theresults from Texas is complicated,because at the time of the AHB’sarrival Varroa mites and trachealmites had eliminated much of theferal European population. Thus, itis difficult to know the extent towhich the loss of EHB colonies re-sulted from parasitic mites or dis-placement by African bees. Dr.Pinto’s work also revealed thatabout 30% of newly establishedcolonies in southern Texas are ofEuropean maternity, suggesting thatmanaged European colonies are pro-ducing a sizable number of swarmsthat move into the wild. However,the evidence suggests that thesecolonies do not survive over time,resulting in a largely African popu-lation.

Although studies of mitochon-drial DNA have taught us a greatdeal about the genetics of the Afri-can honey bee, they do not give usa complete picture. Because mito-chondrial DNA is inherited solelyfrom the mother, it can only tell usabout the contributions of Africanand European queens to a honeybee population. To fully understandthe genetic structure of a popula-tion, we must also examine the DNAof the nucleus of cells, which con-tains genetic material from both thequeen and drones. A large numberof genetic techniques have beenused to determine the degree towhich honey bee populations con-tain African and European nucleargenes (see Box). Each approach pro-vides slightly different information,but all have revealed a consistentpattern: relatively little EHB ge-netic material moves into the Afri-

can population and even less per-sists over time. Throughout LatinAmerica and southern Texas, EHBnuclear genes rarely account formore than 30-35% of the genome(i.e. the bee’s set of chromosomescontaining all of its genes) of wildcolonies, and the percentage is typi-cally far less. Furthermore, the fre-quencies of these genes decline overtime. After several decades, EHBgenes usually account for only 10-20% of the feral genome, suggest-ing that hybrid colonies do not sur-vive in the wild. Thus, feral honeybee populations in invaded areas arecomposed almost entirely of AHBmatrilines, with predominantly Af-rican nuclear genomes.

African and European honeybees do hybridize and some Euro-pean genes have become incorpo-rated into the feral AHB population.It is now unarguable that the intro-duced bee in the western hemi-sphere is no longer genetically iden-tical to the ancestral Apis melliferascutellata population in Africa fromwhich is was derived. The fact thatAHB will interbreed with the EHBand produce hybrid colonies is notsurprising, because they are racesof the same species. What is muchmore surprising is how little Euro-pean genetic material has becomepermanently incorporated into theAfrican population, given the ini-tially small size of the introducedAfrican population, the large Euro-pean population, and nearly 50years of interbreeding.

Thus, studies of both mitochon-drial and nuclear DNA have giventhe same results: The AHB has re-tained a largely African genome asit colonized the western hemi-sphere, despite continued inter-breeding with European bees. In-deed, throughout much of its rangein the New World, the invadinghoney bee has remained essentiallyAfrican in its nesting biology, for-aging, swarming and absconding be-havior. For these reasons, we referto the descendents of Apis melliferascutellata in the Americas as Afri-can bees. We reserve the terms“Africanized bee” and the“Africanization process” to refer spe-cifically to colonies that arise fromEuropean queens mated with Afri-can drones. The ability of the AHBto retain its African nature and dis-place European honey bees is oneof the most amazing and mysteri-ous aspects of the invasion process.In the next article, we explore avariety of factors that may contrib-ute to this phenomenon.

Figure 4. Introduction of Apismellifera scutellata into Bra-zil began in 1956. Within 50years this tropically adaptedrace of bee colonized most ofSouth America and all of Cen-tral America. It entered the U.S.in 1990 through south Texasand is now permanently estab-lished throughout the south-western states and southernCalifornia. Throughout itsrange in the New World, theAHB shows a remarkable abil-ity to displace resident EHBcolonies.

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The African Honey Bee IIThe African Honey Bee IIThe Displacement Of European Honey

Bees by African Bees In The New WorldStan Schneider, Gloria DeGrandi-Hoffman, Deborah Smith, David Tarpy

Stan SchneiderStan SchneiderStan SchneiderStan SchneiderStan Schneider received his PhD in Animal Be-havior from the University of California at Davis andis now at the University of North Carolina at Char-lotte. His main areas of research are honey beecommunication and the biology and behavior of theAfrican honey bee.


Deborah Smith Deborah Smith Deborah Smith Deborah Smith Deborah Smith received her PhD in Neurobiologyand Behavior from Cornell University and post-doc-toral training in molecular biology at the Laboratoryfor Molecular Systematics at the University of Michi-gan. She is now at the University of Kansas, study-ing mitochondrial DNA analysis, honey bee biogeog-raphy and honey bee population biology.


In our first article on the Afri-can honey bee (AHB), we explainedhow differences in the behavior andnesting biology of A. m. scutellataallowed it to thrive and spread at aphenomenal rate throughout LatinAmerica, largely displacing Euro-pean honey bees in all colonizedregions. In addition, despite re-peated interbreeding between Afri-can and European bees, in mostareas the AHB has not blended withthe EHB. Rather, it has largely re-tained its African genetic make up.This means that European traitsbrought into the African populationthrough matings with Europeanbees are being lost from the popu-lation. The failure to incorporateEuropean characteristics is at theheart of the success of the AHB inthe Americas and the biological andeconomic impacts it creates. Thus,to fully understand the African beeinvasion and the effects it may have

in the U. S., it is essential to un-derstand how it interacts with andreplaces European bees.

There is no single factor respon-sible for the displacement of Euro-pean colonies and the loss of Euro-pean characteristics in areas whereAfrican bees immigrate. Rather, atleast six different mechanisms con-tribute to varying extents to the lossof European patrilines (lineages ofthe drones) and matrilines (lineagesof the queens). Some of these fac-tors may be of greater importancein managed apiaries, whereas oth-ers play a stronger role in feral honeybee populations.

Swarming BehaviorOne of the major differences

between European and Africanhoney bees is the rate of colonypopulation growth. While Europeanbees have been selected primarilyfor honey production and storage tosurvive longer, colder winters, Afri-can colonies have a greater empha-sis on pollen collection and a morerapid conversion of pollen intobrood. African bees devote two tofour times as much comb area tobrood rearing compared with Euro-pean bees. The resulting highergrowth rates allow for increased Af-rican swarm production (Fig. 1). Inthe Neotropics, African colonies canincrease 16-fold per year, whilemaximum increases in wild Euro-pean colonies in temperate areasare only three- to six-fold. Conse-quently, the density of African colo-nies can increase quickly in thewild, especially in regions withsmall populations of Europeanhoney bees. This in turn gives theAHB a numerical advantage thathelps it out compete and displaceEHB colonies.

Negative Heterosis in HybridBees

A factor that has been proposedrepeatedly to explain the loss ofEuropean traits from African popu-lations is reduced fitness and sur-vival of hybrid bees (Fig. 2). Severalresearchers have proposed thatthere may be incompatibilities be-tween European and African genesthat make it difficult for hybrid colo-nies to persist unless they aremanaged by humans. In particular,it is thought that European mater-nal and African paternal genes maybe especially incompatible. Thiswould help to explain the drasticloss of European matrilines in feral

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Figure 1. A swarm of African bees. Afri-can colonies swarm more often than Euro-pean colonies and quickly establish largewild populations, which helps them outcompete European colonies. African colo-nies are also much more likely to abscond(abandon a nest site) and migrate duringdearth periods. This increased colonymobility further helps to spread the AHBquickly throughout a colonized region.


honey bee populations, despiterepeated opportunities for“Africanized” European swarms tomove from commercial apiaries intothe wild. The reduced fitness in hy-brids (referred to as negative het-erosis) is a controversial topicamong honey bee researchers, butthere are two main lines of evidenceto suggest that it occurs.

First, European/African hybridshave lower metabolic rates than“pure” African or European bees.This was first demonstrated for hy-brid workers in 1993 by Dr. JonHarrison of Arizona State Universityand Dr. H. Glenn Hall of the Uni-versity of Florida. More recently, Dr.Harrison’s lab has shown that hy-brid queens also have lower meta-bolic capacities. The lower meta-bolic rates could reduce flying abil-ity, which in turn could negativelyaffect foraging, swarming, and mat-ing flights.

A second line of evidence forreduced fitness in hybrid beescomes from studies of the shape ofthe honey bee wing. Dr. StanSchneider of the University of NorthCarolina at Charlotte and Dr. GloriaDegrandi-Hoffman of the USDA CarlHayden Bee Research Center inTuscon, AZ used instrumental in-semination to create crosses be-tween European queens and Africandrones (i.e. EHB/AHB hybrid work-ers), “pure” African workers (African

queens mated with African drones),and “pure” European workers (Eu-ropean queens mated with Europeandrones) and then raised them in thesame colony. On the day that theworkers emerged as adults, theywere collected and the shape of theleft and right forewing of each beewas compared using a mathemati-cal process. The wings of hybridworkers were slightly less sym-metrical that those of the pure Af-rican workers. The ability to buildleft- and right-side structures dur-ing an animal’s embryonic develop-ment is genetically controlled. If thegenetic programs for developmentare stable, then the two sides of ananimal’s body are more symmetri-cal. Conversely, if the genetic pro-grams have less stability, then theanimal often has more asymmetri-cal structures. Thus, the greaterasymmetry in the wings of hybridworkers suggests that they havelower developmental stability than“pure” African bees, which may fur-ther indicate incompatibilities be-tween European and African genes.In combination, the lower metabolicrates, possible developmental prob-lems, and greater asymmetry of hy-brid workers would contribute to theloss of European characteristicsand might help to explain why hy-brid colonies do not persist over timein the wild.

Mating Advantages for AfricanDrones

When African bees colonize ar-eas with resident European popu-lations, queens will mate with bothEuropean and African drones (Fig.3). However, matings with Europeandrones decline over time resultingin a reduction of Europeanpatrilines in managed and wild colo-nies. There are several factors thatmay contribute to an African dronemating advantage in invaded areas.First, AHB colonies produce moredrones than EHB colonies of thesame size. Second, the more nu-merous AHB drones will drift intoEuropean colonies, which sup-presses the production of EHBdrones. Third, AHB colonies expe-rience high rates of queen loss andthe resulting queenless coloniesrear large numbers of worker-pro-duced drones. Fourth, there may bedifferences in mating-flight timesthat increase the chance of EHB

queens mating with African drones,but decrease the chance of AHBqueens mating with Europeandrones. Finally, in a recent study,Dr. Gloria DeGrandi-Hoffman, Dr.Stan Schneider and Dr. David Tarpyof the North Carolina State Univer-sity instrumentally inseminatedqueens with semen from an equalnumber of African and Europeandrones and then monitored thenumber of AHB and EHB workersproduced for six months. They foundthat significantly more AHB work-ers than expected were produced,which suggests that African spermmay have an advantage over Euro-pean sperm, even if queens matewith the same numbers of dronesof both types. An African drone mat-ing advantage would result in therapid loss of European paternalgenes and may be an important fac-tor in the AHB’s ability to displaceEuropean bees.

African-patriline AdvantagesDuring Queen Replacement

European genes are also lostwhen colonies in invaded regionsraise new queens. When a colonyswarms or supersedes its queen,workers rear up to a dozen or morevirgin queens (VQs) in specially con-structed cells. Virgin queens arehighly aggressive toward one an-other and battle to the death untilthere is a sole survivor, who thenbecomes the new laying queen ofthe colony. A virgin queen can elimi-nate her “rival” sister queens in two

Figure 2. Worker, drone and queen honeybee. AHB/EHB hybrid workers andqueens have lower metabolic rates thanAfrican bees. Also, the left and right forewings of EHB/AHB hybrid workers areless symmetrical when compared to oneanother than are the wings of African work-ers. This may further reflect incompatibili-ties between African and European genesthat negatively affect larval development.In combination, the physiological and de-velopmental differences might make hy-brid bees less competitive and less effi-cient at foraging, swarming and mating.As a result, hybrid colonies may not sur-vive well in the wild, which would contrib-ute to the loss of European traits.

Figure 3. AHB drones may have a mat-ing advantage over EHB drones. Africandrones are more abundant, take matingflights at times that may increase theirchances of mating with European queens,and will drift into EHB colonies and sup-press the rearing of European drones.Also, even if queens mate with an equalnumber of AHB and EHB drones, they maypreferentially use African sperm to fertil-ize their eggs. AHB drone mating advan-tages result in the rapid spread of Africangenes and the loss of European genes.


ways. First, she will attack queencells and sting her rivals to deathbefore they emerge. Second,emerged VQs seek out each otherand attempt to sting one another.Workers often attempt to influencethe interactions of virgin queens andmay play a major role in determin-ing which VQ will “win” the elimi-nation process.

In colonies where queens matewith a combination of African andEuropean drones, the colony popu-lation is made up of African- andEuropean-patriline bees. Duringqueen replacement, these “mixed”colonies will rear VQs from bothpatrilines. Recent research con-ducted by Dr. Gloria DeGrandi-Hoffman and Dr. Stan Schneiderhas shown that African-patrilineVQs have a strong advantage dur-ing queen elimination.

Workers in mixed colonies raisesimilar numbers of African- andEuropean-paternity queen larvaeand devote equal care to both queentypes. However, African-patrilineVQs develop faster and emergesooner, which may give them moreopportunities to eliminate rivalsconfined in queen cells. In 70% ofthe mixed colonies studied, an Af-rican-patriline VQ was the firstqueen to emerge, and the first-emerging queen usually became thenew laying queen of the colony.

African-patriline VQs also ap-pear to be better fighters than theirEuropean-paternity sister queens(Fig. 4). African VQs kill significantlymore of their emerged rivals thendo the European VQs. African-pa-

ternity VQs also produce morebouts of “piping” (a high-pitched,pulsed sound) than European-pater-nity queens. The function of pipingis unclear, but it is somehow re-lated to fighting ability. VQs thatpipe more survive longer, kill agreater number of rivals and aremore likely to become the new lay-ing queen. Workers in mixed colo-nies also interact with African-patriline VQs more often than theydo with European-patriline VQs. Inparticular, workers perform more“vibration signals” on African VQs(Fig. 4). The vibration signal may pro-mote queen fighting success, be-cause queens that receive more sig-nals kill more rivals and are morelikely to survive the queen elimina-tion process. In combination, be-cause of their earlier emergence,greater fighting ability, piping activ-ity and vibration signals received,African-patriline VQs are five timesmore likely to survive the queen-elimination process than are theirEuropean-paternity sister queens.When the African-paternity queenstake mating flights in invaded ar-eas, they will mate largely or en-tirely with AHB drones, resulting in

increasing Africanization with eachsuccessive queen replacementevent. A survival advantage for Afri-can-patriline virgin queens maytherefore play a major role in therapid loss of EHB characteristics ininvaded regions.

Dominance of African GenesIn invaded areas, European

colonies headed by open-matedqueens often exhibit African behav-ioral traits, even if they mate witha relatively high proportion of Euro-pean drones. African genes maytherefore be dominant for somecharacteristics. Dominance of Afri-can genes has been most thoroughlystudied for defensive behavior. Af-rican honey bees exhibit a more in-tense nest defense behavior thanEuropean bees. Colonies composedof workers that are crosses betweenEuropean queens and Africandrones show levels of defensivenessthat do not differ from those of ‘pure’African bees (i.e., workers having anAfrican matriline and patriline).These findings suggest that Africandefensive behavior may be geneti-cally dominant. Because a honey beequeen mates with an average of 12drones, the level of defensivenessexhibited by a colony will dependupon the number of workers siredby African drones. As explainedabove, queens in invaded areasmate disproportionately with Africandrones and may preferentially useAfrican sperm to fertilize their eggs,which can increase the level of de-fensiveness in a relatively shortperiod of time. In addition to geneticdominance, colony defense behav-ior also is affected by alarm phero-mone. When African-patriline work-ers defend their colony, they releasemore alarm pheromone and thiscould stimulate European-paternityworkers that otherwise would notrespond to the initial disturbanceto exhibit defensive behavior. Thus,the presence of African-patrilines in

“To fully understand the African beeinvasion and the effects it may have inthe U.S., it is essential to understand

how it interacts with and replacesEuropean bees.”

Figure 4. Two virgin queens fighting to the death (photo courtesy of Ken Lorenzen).When African and European-paternity VQs are present in the same colony, the Africanqueens kill more of their rivals and produce more bouts of “piping” (a sound signal thatmay promote fighting success). African VQs also receive more “vibration signals,” whichconsist of workers grabbing a VQ and rapidly vibrating their bodies up and down forone to two seconds (see drawing). Queens can be vibrated hundreds of times an hourand VQs that receive more signals survive longer and kill more rivals. In combination,the greater fighting ability, piping activity and vibration signals received results inAfrican-patriline queens winning the rival elimination process and becoming the newlaying queens of their colonies. This in turn results in the rapid loss of EHB character-istics.

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a colony could increase its defen-sive response even if many of theworkers have European paternity.

Nest UsurpationOne of the most unique behav-

iors of African honey bees is theirability to usurp European colonies.Nest usurpation is a form of socialparasitism where small Africanswarms invade European coloniesand replace the resident queens(Fig. 5). Nest usurpation results inthe complete and instantaneousloss of European matrilines andmay partially explain the rapid lossof European characteristics in re-gions where African bees are estab-lished. Dr. Stan Schneider, Dr.Gloria DeGrandi-Hoffman and Dr.David Gilley of the Carl Hayden BeeResearch Center in Tucson studiednest usurpation in southern Ari-zona and found that annual usur-pation rates can reach 20-30%.Furthermore, there are strong sea-sonal patterns for nest usurpation.A minor peak of usurpation activityoccurs during the spring-summermonths, which corresponds with thereproductive swarming season forhoney bees in southern Arizona.However, the greatest usurpationactivity occurs during the fall-win-ter months, which corresponds tothe period of seasonal abscondingwhen African colonies in southernArizona abandon their nests tosearch for better foraging condi-

tions. Usurpation swarms may bereproductive or absconding swarmsthat are too small to successfullyestablish a nest, and instead adopta strategy of invasion and parasit-ism. Nest usurpation may be animportant part of the annual colonycycle in southern Arizona, and playan important, although seasonallyand regionally variable role in thespread of African bees.

How African swarms find andinvade host colonies is unclear.Pheromone cues associated withthe presence and condition of aqueen may be involved in the loca-tion of susceptible hosts. We havefound that queenless colonies andthose with a caged queen are par-ticularly susceptible to invasion.This raises important concernsabout the manner in which Euro-pean colonies are maintained inAfricanized areas. The most com-monly used method to maintainEuropean characteristics is to an-nually requeen colonies with newEuropean queens. The old Europeanqueen is removed and the newqueen is confined in small cage forseveral days and then released. Wehave found that if requeening isconducted during the swarming orabsconding season, it may actuallyincrease the chance of colonies be-coming African, rather than help toretain European characteristics.

Queenless and caged-queenconditions are not the only factorsthat make colonies susceptible tousurpation. Queenright coloniescan also be invaded, suggesting thatcues other than those emanating

Figure 5. An African swarm usurping aEuropean colony. Usurpation swarms aresmall reproductive or absconding swarmsthat invade an EHB nest, replace the Eu-ropean queen, and take over the colony.Queenless EHB colonies and those with acaged queen are particularly susceptibleto usurpation. In southern Arizona, an-nual usurpation rates can reach 20-30%,suggesting that usurpation is an impor-tant factor in the displacement of Euro-pean in parts of the southwestern U.S. Insouthern Arizona, peak usurpation activ-ity occurs from October - December, whichcorresponds to the absconding season forAfrican bees in the Tucson basin.

from the state of a colony’s queenare involved in host location. Whilesome overt aggression occurs dur-ing the invasion process, phero-mone signals may also help usur-pation swarms gain entry into EHBcolonies. Invading African swarmsmay produce pheromone signalsthat circumvent the defensive re-sponses of EHB colonies and alterworker-queen interactions in a man-ner that contributes to the loss ofEHB queens. However, the mecha-nisms that regulate nest usurpationrepresent one of the least under-stood aspects of the African bee in-vasion process.

ConclusionsIn summary, there is an array

of behavioral, physiological and ge-netic factors that contribute to theAHB’s ability to displace Europeanhoney bee colonies in invaded ar-eas. Throughout much of LatinAmerica, these factors have helpedto preserve the genetic structure ofthe African honey bee populationdespite repeated interbreeding withEuropean bees. The available evi-dence also suggests that thesesame factors are contributing to thespread and success of the AHB inthe southwestern U.S. However,what the African bee will do in theU. S. in the future is far from clear.In the final article of this series,we explore the past and possiblefuture spread of the AHB through-out the U.S., the factors that maycontribute to its distribution andthe impacts it is likely to have onbeekeeping and agriculture. B CB CB CB CB C


The African Honey Bee IIIThe African Honey Bee IIIThe African Honey Bee Has Arrived – So Where

Do We Go From Here?Gloria DeGrandi-Hoffman, Mona Chambers, Stan Schneider, David Tarpy, Deborah Smith

Stan SchneiderStan SchneiderStan SchneiderStan SchneiderStan Schneider received his PhD in Animal Be-havior from the University of California at Davis andis now at the University of North Carolina at Char-lotte. His main areas of research are honey beecommunication and the biology and behavior of theAfrican honey bee.


Deborah Smith Deborah Smith Deborah Smith Deborah Smith Deborah Smith received her PhD in Neurobiologyand Behavior from Cornell University and post-doc-toral training in molecular biology at the Laboratoryfor Molecular Systematics at the University of Michi-gan. She is now at the University of Kansas, study-ing mitochondrial DNA analysis, honey bee biogeog-raphy and honey bee population biology.


Mona Chambers Mona Chambers Mona Chambers Mona Chambers Mona Chambers is a Research Technician at theCarl Hayden Bee Research Center in Tucson, Ari-zona, and Coordinator of the Honey BeeMorphometrics Laboratory. She received her Bach-elors degree from the University of Arizona.

In the first two parts of thisseries, we discussed the history ofAfrican honey bees (AHB) in the NewWorld and the biological and behav-ioral bases for their successful es-tablishment. In this third and finalpart of the series, we address thepractical aspects of the AHB migra-tion into the U.S. We begin with abrief overview of the history of AHBin the U.S. and then discuss somebehavioral features that might in-dicate that a colony is in the earlystages of Africanization. We thenreview the current methods of de-termining whether or not a sampleof bees is AHB. We also discuss thepotential future range of AHB andhow they might spread throughoutthe U.S., as well as address publicperceptions of AHB, beekeepers andwhite boxes, and the role of themedia. Finally, we provide some ad-vice on what to do if you suspect

that a colony is Africanized, includ-ing some guidelines concerning whatbeekeepers can do to prevent or re-verse Africanization.

The AHB in the U.S.The African honey bee was first

detected in the U.S. in 1990 in southTexas (Fig. 1). For the next threeyears, their population was confinedto southern Texas. In 1993,however, the AHB was detected inArizona when a dog was severelystung by honey bees. Over thefollowing year, feral honey beeswere sampled in the southernregion of Arizona, and AHB werefound across the state. In 1995,AHB were detected for the first timein New Mexico and southernCalifornia. AHB then spreadnorthward in Arizona and NewMexico and, by 1998, they weredetected in Nevada. The beescontinued their migration northwardin every state where they becameestablished. By 2004, the bees hadmigrated through Texas and weredetected in the southern mostcounties of Oklahoma.

For reasons that are yet unclear,the spread of AHB eastward out ofTexas stalled in the Houston regionfor several years. One explanationfor why the population did notexpand east was that areas withmore than 55 inches of yearlyrainfall could not support AHBpopulations. The reasoning for thiswas that the higher humidity mightenable Varroa mites to have greatersurvival rates in colonies so that

most feral AHB would succumb toVarroa infestations. The propensityof AHB colonies to increase broodproduction in response to rainfallalso was given as a possibleexplanation for the failure of AHBto expand eastward. Since Winterrains in east Texas are not followedby blooms on flowering plants, itwas assumed that the AHB colonieswould starve.

Despite their temporaryinability to spread east of Texas, by2005 the AHB expanded eastwardfrom Houston. Most recently, theAHB has become established inFlorida, western Louisiana, and inthe southwest region of Arkansas.It remains unclear how Floridabecame populated, but it seemslikely that the bees entered on cargoships through commercial shippingports.

How do I know if my bees areAfricanized? Behavioral At-tributes

Extreme nest defense has beenthe calling card of AHB; a stingingincident usually is the first indica-tion that AHB are present. In suchcases, an inordinate number of bees– usually from a colony in a struc-ture like a shed or garage ratherthan a managed hive – sting an un-suspecting person or pet that inad-vertently disturbed their nest.Stinging incidents from confirmedAHB colonies tell us several thingsabout the local feral honey beepopulation. First, the colony is prob-ably not the only AHB nest in the

Figure 2.Comparison of

European (left) andAfrican bees (right)

on a brood frame.Notice how theEuropean bees

cover the brood,while the African

bees leave itexposed.


area. The drones that matedwith the queen likely derived fromother AHB colonies. The stinging in-cident also indicates that coloniesof AHB in the area are numerousand successful enough to reardrones. Finally, there are sufficientnumbers of AHB colonies so thatqueens are mating with enoughdrones that workers are expressingnest defense characteristics thatare unlike those of EHB colonies.

While the general public mightnotice that a colony is Africanizedonly when a severe stinging incidentoccurs, beekeepers might noticemore subtle changes in colony be-haviors that could indicate lowerlevels of Africanization. First, AHBworkers may persistently fly into thehelmet or mesh of the bee veil whena colony is first opened. Second,AHB workers will move to the cor-ners of the comb and expose thebrood when a frame is removed froma hive (unlike EHB, which usuallyremain on the frames and cover thebrood) (Fig. 2). Populous AHB colo-nies will also form clumps of beeson the sides of frames and attachto surfaces against which the frameis set. Third, AHB colonies oftenconstruct a single queen cell on ahoney frame, particularly in popu-

lous colonies. Finally, beekeepersmight also see workers with shinyblack abdomens that look like smallvirgin queens (Fig. 3). Dr. GloriaDeGrandi-Hoffman of the USDA CarlHayden Bee Research Center inTucson has recently demonstratedthat these shiny black bees are“intermorphs” that have character-istics of both workers and queens.How and why intermorphs arereared in colonies remains unclear,but they are signs that AHB colo-nies are in the area.

Perhaps one of the most ex-traordinary behavior exhibited byAfrican bees is invading and usurp-ing colonies of EHB (see Part 2: TheDisplacement of EuropeanHoney Bees by African Bees in theNew World). While the behaviorsdescribed above are characteristicof Africanized bees (i.e., those aris-ing from European matriline queensmated with African drones), nestusurpation behavior appears to beassociated with “pure” African bees(i.e., African matriline queensmated with African drones). Re-searchers have yet to collect aswarm that invaded an EHB colonythat does not have African mito-chondrial DNA, which means theworkers in the swarm were produced

by an African queen (see Part 1: TheAfrican Honey Bee: A Case Studyof a Biological Invasion). Usurpa-tion swarms can look like a clumpof bees hanging out at the entranceof a colony that is over crowded es-pecially during the warmest part ofthe day. However, upon closer ex-amination, bees might be seenfighting and dead bees might befound at the colony entrance or onthe ground around the hive. Thedefinitive characteristic of a usur-pation swarm is that one or morequeens are found in the center ofthe swarm (Fig. 4). Usurpationswarms can present serious prob-lems to managed colonies: if queensare not marked, and the swarm ismisdiagnosed as simply an over-crowded colony, an EHB colony willbe invaded and will immediatelybecome converted to an Africancolony.

Methods of IdentificationDespite behavioral differences,

the only way to be certain if beesare Africanized is to have them ana-lyzed by an objective test. There aretwo general categories of tests todetermine Africanization:morphometrics and DNA analysis.We have previously reviewed the

Figure 1. The current distribution of Africanized honey bees in the U.S. The map iscourtesy of the USDA-ARS and can be found at: www.ars.usda.gov//Research/

docs.htm?docid+11059&page+6


various DNA analyses that arecurrently available to distinguishAHB from EHB (see Part 1: The Af-rican Honey Bee: A Case Study ofa Biological Invasion). Here, webriefly describe the morphometricanalyses that are commonly usedto detect AHB.

Any analysis that differentiatesgroups of bees based upon theirmorphology is called morphometrics.Morphometric analysis uses a sys-tem of measuring morphologicalcharacteristics to determine honeybee type by a statistical techniquecalled discriminant analysis. Thetechnique determines whether beesare EHB or AHB based on body mea-surements. While they are difficultto distinguish with the naked eye,AHB workers are, on average,smaller than EHB workers. By care-fully and accurately measuring dif-ferent body parts, researchers candetermine the likelihood that a par-ticular sample of bees are AHB orEHB (see box on next page).

The benefit of morphometricanalyses is that they are relativelyinexpensive and can be accom-plished fairly rapidly (particularly byusing a protocol called FABIS thatmeasures only the wings). A limita-tion of morphometrics, however, isthat it does not provide information

on whether Africanized traits arederived from the queen (matriline),the drones she mated with(patriline), or both. Knowingwhether a colony has Africanmatrilines or patrilines providesinsights into the state of the AHBpopulation in the area. If the beeshave EHB matrilines and Africanpatrilines, the invasion is probablyin the early stages, but if Africanmatrilines are detected, the inva-sion probably has been ongoing forsome time. While DNA analyses canprovide this valuable genetic infor-mation, they can be relatively ex-pensive and time-consuming com-pared with morphometric tests.

Many states now perform mor-phometric or genetic analyses of

bee samples. In addition, the USDAAfricanized Honey Bee Identifica-tion Laboratory housed in the CarlHayden Bee Research Center(CHBRC) in Tucson, Arizona willanalyze honey bee samples for stateapiary inspectors, maritime portauthorities, and other USDA agen-cies such as Animal Plant andHealth Inspection Service (APHIS)and Plant Protection and Quaran-tine (PPQ). Samples for morphomet-ric analysis should be collected byplacing 30 to 50 adult honey beesin a small container or vial contain-ing just enough 70% ethyl alcoholto cover the bees. The name of thecollector, collection date, and loca-tion need to be included with thesample.

Intermediate Morph European Worker

Figure 3. Examples of worker bees,intermorphs from African colonies and anAfrican queen; note the differences be-tween the abdomens of a Europeanworker and an intermediate morph. Noticethe differences in the amount of branchedhairs on the worker abdomen, and theabsence of them on the intermorph.

Be vigilant1. Mark all queens; no exceptions.2. Regularly check hives for un-

usual external clumping ofbees, as these may be parasiticAHB swarms.

3. Requeen any colony that isunacceptably defensive or con-tains an unmarked queen; useonly queens from a known EHBsource.

4. Inspect hives for behavioralsigns of AHB, particularly afterthey are transported in and outof known AHB areas.

5. Send suspect samples to au-thorities for morphometric orgenetic testing; place 30 to 50adult bees in a small container,fill with enough 70% ethyl alco-hol to cover the bees, and labelwith contact information, col-lection date, and location.

6. In an Africanized area, attemptto make all potential AHB nest-ing sites “bee tight”; avoid stor-ing empty beehives outdoors.

Be responsive1. Keep AHB incidents in an ap-

propriate context during mediainterviews. DO NOT includebox hives in filming about sting-ing incidents, as this promotesa negative perception of allhoney bees. DO include man-aged hives in filming about thebenefits of beekeeping.

2. Avoid speculation and answeronly those questions to which

What beekeepers can do to minimize theAfricanization process

you know the answer. Parts 1& 2 of this series of articles weredesigned to provide the back-ground information necessaryfor explaining the AHB to themedia and public.

3. Don’t sensationalize defen-sive behavior by using terms like“aggressive” or “vicious.”

4. Make clear the relative risk ofthe AHB; the number of deathseach year from stinging inci-dents are far fewer than dog at-tacks, food allergies, even light-ening strikes.

Be proactive1. Emphasize that beekeepers are

on the front lines of defense—beekeepers are part of the so-lution, not the problem.

2. Be a good neighbor and informanyone who may be in closeproximity to your hives; educat-ing them about the benefits ofhoney bees and the relativerisks of AHB should lessentheir fears.

3. Establish and maintain lines ofcommunication between localbeekeepers, first responders,and local officials.

4. Make people aware of the dis-tinction between yellow jacketsand bees, as many people mis-take wasps for honey bees. In-creased public awareness of thedifferent types of stinging in-sects will reduce the number oferroneous AHB reports.


the AHB cannot survive a pro-longed Winter, which will slow orprevent its movement into northernstates. However, we now know thatferal AHB populations are estab-lished in areas above 5000 ft in Ari-zona and New Mexico and can sur-vive through the Winter. Thus, atthis point we do not know the ex-tent to which the AHB will spreadin the U.S. or how quickly the inva-sion process will proceed. Further-more, we cannot predict in whichregions the AHB will become per-manently established or be a “sea-sonal visitor,” in which colonies maymigrate in during Spring and Sum-mer but die out during the Winter.The ultimate distribution of the Af-rican bee in the U.S. will depend ona combination of its inherent abil-ity to spread and survive in new ar-eas and human assisted move-ments that might transport the beepast barriers that otherwise wouldhalt its progression.

What should beekeepers do tominimize Africanization?

The first step in minimizingAfricanization is for beekeepers tobe vigilant. Queens in colonies thatare transported into or reside inAfricanized areas should be markedand their hives should be inspectedon a regular basis (see Box 2). Anyhive that contains an unmarkedqueen should be requeened with anew queen of known European de-scent. The new queen should beintroduced behind a push-in cageover emerging brood (Fig. 5). AHBworkers often kill EHB queens in-troduced in shipping cages. Thepush-in cage should be moved ev-ery two to three days, and thisshould be repeated at least threetimes before releasing the queen.After the queen is released, thecolony should be examined every 10-14 days for six weeks to ensure that

the introduced queen has been ac-cepted, and to destroy any super-sedure queen cells that the work-ers may construct.

Another important way thatbeekeepers can minimize the impactof the AHB is to respond to reportsof AHB in an appropriate and timelymanner. In many areas of the U.S.where AHB have already becomeestablished, the initial detectionoccurred from a stinging incident.It is likely that the same will hap-pen in newly established areas.These events are sure to make thelocal TV news and grace the frontpages of local newspapers. Suchincidents are indeed serious, butthey can be easily sensationalized.If they are, the public may becomefearful of all bees and the beekeepermight be perceived as part of theproblem. To mitigate the damagefrom sensationalized news reports,beekeepers and beekeeping organi-zations need to have sound and co-herent information concerning theAHB. They must also adopt strate-gies to work effectively with themedia. After a stinging incident, areporter might want to interview alocal beekeeper. If this occurs, avoidconducting interviews with man-aged beehives in the background,because the image conveys to thepublic that all managed coloniescontain AHB. Instead, the back-ground for news stories about AHBshould have a structure, such as acarport or shed, where an AHBcolony is or can become established.Also, avoid having reporters filmbees on frames, as a large numberof bees may be taken out of contextwhen the story appears. Instead,emphasize the importance of honeybees to U.S. agriculture, the ben-efits of local honey and pollination,and the relative risks of bee stings.

Finally, beekeepers can help bybeing proactive. The main message

that beekeepers need to communi-cate to the public is that managedcolonies are part of the solution andnot part of the problem. Becausebeekeepers manage the genetics oftheir colonies, they are ensuringthat genes associated with reducednest defense behavior remain in thehoney bee population. Thus, man-aged colonies are the genetic bufferbetween the public and the feralAHB population. By projecting theAHB issue in an accurate and ra-tional manner, beekeepers will beable to adjust to the changing land-scape of beekeeping in the countryand address the AHB in the comingyears.

General ConclusionsIn closing, the goal of this se-

ries of three articles was to providebeekeepers with the backgroundinformation and management tac-tics necessary for coping with theAHB, and for handling the media andpublic attention it invariably gener-ates. The African honey bee is nowa permanent resident throughoutthe southwestern states and Cali-fornia, and seems destined to be-come part of the landscape in thesoutheastern states as well. As hasoccurred throughout Latin America,the AHB is likely to displace feralEHB colonies and have a substan-tial impact on the management ofEuropean colonies throughout thesouthern tier of the U.S. The ulti-mate distribution of this highly in-vasive honey bee cannot be pre-dicted at present, and only time willtell the economic and public welfareimpacts that it will have in ourcountry. The only certainty is thatthe AHB is now a feature of U.S.beekeeping. But, just as we havelearned to cope with introducedmites and beetles, we will also learnto cope with this latest challengeto beekeeping – and perhaps in thelong run we will realize benefits fromdoing so. Studies in Mexico andCentral and South America havesuggested that under some condi-tions the AHB is a highly efficientpollinator, and might be more resis-tant to Varroa mites than the EHB.Whether these benefits will be re-alized in the U.S. remains to beseen. Nevertheless, by being pre-pared and managing our colonieseffectively, we can ensure the con-tinuation of a viable beekeeping in-dustry in the U.S. that controls, andperhaps some day incorporates,this new arrival.

Figure 5. Europeanqueen introduced in anAfricanized colonybehind a push-in cage.The arrow is pointing tothe marked queen.

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Documents

The African Honey Bee - UNC Charlotte Pagestion, African honey bee genetics and biology. Deborah Smith received her PhD in Neurobiology and Behavior from Cornell University and post-doc-toral