Killer bees

If we are feeble or allergic, we can react very badly to a hymenopteran bite. Only one bite of a wasp or of a bee may kill a man, while it may not affect others. If one is attacked by a swarm, a disastrous result may well be imagined. One can become allergic later on, that is after a few bites, one may develop sensitivity to bee venom. So being careless about bee stinging may eventually prove fatal.

It has been said before that PJ was chased once in Ethiopia by a swarm of Apis mellifica adansoni, the Abyssinian variety, which were trying to bite the head, with only vestige of fur in the naked ape (see the chapter on "Interesting ways of bees and dung beetles"). In Africa monkeys, as well as the bears in other countries, are cunning honey robbers. Certain birds in Africa join small mammals in attacking wild hives. Hence bees in Africa have learnt how to protect themselves, and attack readily all furry and feathered animals with ferocity.

Most of African bees, all African races of A mellifera,, are ferocious, active throughout year, and build generally their hives in any available cavity. In Ethiopia, the man-made hives are very primitive and made of bundles of firewood suspended from trees. Once PJ travelled there in a DC3, and a co-passenger had inside a metal can full of bees with its top filled with grasses. Slowly the bees escaped one by one, and the cabin was full of buzzing insects. The poor bees were more afraid than we and did not try to bite. It is not rare in Sudan to see the bees installed at the entrance of a swimming pool. This they do to repel potential bathers, when the pool is not to be used. In Dakar, often the bees try to establish themselves on lamp posts. African bees get disturbed easily, and very often in the evening, when the lamps are turned on, the bees, disturbed by the light and the heat, become furious and try to bite. It was the South African variety, which was introduced in Brazil in 1957, Apis melllifera scuteRata, and its crossing with Apis melllifera mellifera which produced a ferocious hybrid, nearly a semi-species, named the Africanized bee.

Bees can be dangerous also due to toxicity of their honey. Recently in France a bee-keeper praised his Rhododendron honey. It was forgotten by him that honey collected on Rhododendron is toxic for man, but not to the bee. Numerous cases of honey poisoning are known, specially in Asia.

There were in past cases of group poisoning through consumption of Rhododendron honey. Xenophon, in 401 BC, has described in the Anabasis that, when the Greeks once camped in Anatolia, the ones who ate local honey lost their mind, vomited and were victims of a terrible diarrhoea. The soldiers who ate only a little honey seemed completely drunk, but recuperated the next day. Rhododendron, an Ericaceae, is not the only plant to yield poisonous honey. Toxic honeys result from the bee foraging also on Aconit, Colchica, Jusquiame, and Kalmia, a North-American Ericaceae, often cultivated in our gardens. The anthers of that plant are programmed to dust with pollen an eventual pollinator. The toxin of Kalmia is a glycoside, the andrometoxin, and its action can be easily neutralized by simple heating at 40-50 °C.

A poisonous honey may be toxic to man, but does not affect the bee, though the insect can be sensitive to certain pollens, such as Ranunculus and certain tree pollens. Normally bees avoid those plants, but it so happens that they collect pollen from such plants in case of scarcity or drought, and the toxic pollen poisons the honey both for man as well as for bees.

That the bees can produce in certain parts of the world toxic honey is already worrying people. Besides, a badly controlled and untested hybridisation may become a catastrophe at the continental scale, and that is much worse. It was this that happened when an imprudent apiculturist introduced in Brazil, in 1956, a South African race of Apis mellifera, A. m. scutellata. The foreign bee crossing with A. mellifera mellifera has transformed the latter sweet bee of Mount Hymette, praised in the past by Virgil, into an uncontrollable and aggressive bee, ready to rush against any imprudent visitor. In 1957, one year after the introduction, there were 17.39 % cases of bee stinging among Brazilian beekeepers. In 1969 this figure reached 60.69%, and there were many deaths among humans and domestic animals. Since then, the ferocious bee has invaded Amazonia, tropical parts of South and Central America and has reached California and the South West zone of the US below the overwintering line (Jolivet, 1991).

That bee introduction was made in Iracicaba, in Sao Paulo state, in Brazil, by Warwick Kerr who wanted to produce by hybridisation a new race, better adapted to tropics. In Africa, local races of Apis mellifera are more active, and produce, under poor conditions, much more honey. The hives, in Brazil, were equipped with screens allowing exit of honey gathering bees, but not of the queen and the males, which were too big for the size of the openings available. That was the catastrophe. During the absence of the experimenter, a local beekeeper judging the openings in the screens too narrow for the workers coming back with their load of pollen, widened the gaps in the screens. In the following ten days, the colonies swarmed repeatedly and we could count 26 new swarms leaving the hives. The African bees swarmed everywhere, probably by hybridisation with the Italian form (A. m. ligustica), and started a new and more vigorous race, almost a new species, more dynamic, more ferocious, and it started the conquest of the New World. Bees, resulting from hybridisation with the African race, established large feral populations and were replacing resident honey bees. Transvaal genes in the hybrid bees dominated the Italian race, and we reached a complete disappearance of European traits (Taylor, in Resh and Carde, 2003).

These new bees killed beasts and humans (in average 50 men per year) through all Brazil, and there are no years without new cases. In Africa, this insect, though normally aggressive, can be controlled in apiaries. It was not the same in Brazil. Hybridization produced a bee more vicious than the African race itself. The Africanized bees in the New World could be a complex hybrid of A. mellifera (Germany), A. mellifera ligustica (Italy) and A. mellifera scutellata (Transvaal), but certain authors believe that it is only A. m. scutellata at the pure stage, probably due to a possible incompatibility of the nuclear and mitochondrial genomes of the remaining three races.

The eventual spread limits of the killer bees in America are difficult to evaluate. All depends on their adaptability to cold. After the accidental introductions in California in 1985, it seems that the Africanized bees will establish in the US in the southwestern states, and eventually in Florida. Due to stinging incidents, American beekeepers will hesitate to accept the bee for local apiculture. The new bee has penetrated in Argentina and a hybrid zone reaches the northern parts of the country.

Economically the Brazilians are rather satisfied with the new bee, which produces twice as much honey as A. m. Hgustica and four times more than A. mellifera s. str. Only many more precautions have to be taken when approaching the hives, and all beekeeper equipment must be used, when collecting honey. The behaviour of these bees is really dreadful, because, when they are disturbed just by someone approaching, it takes one hour before they calm down. In European farms disturbed bees quieten down in five minutes. The movement of Africanized bee swarm covers at least 100 meters, while European bees swarms stop generally after only 10 meters.

In 1988, microprocessors were fixed on the pronotum of the killer bees, to follow their migrations. Solar cells charge the device, which send infrared signals captured by a scanner. That way the wing beatings were measured, and it was noted that the movements were obviously quicker in the African than in the European race. A m. scutellata lives in a more dangerous surrounding than A. m. ligustica.. Aggressiveness is an answer to the natural aggressions faced by the insect in its original surroundings.

The Africanized bee produces more honey, and it can probably be genetically improved by new crossings. However, so dominant are the African characters that so far all attempts have been futile. As it reproduces in the wild state too, their eradication is impossible. If a well equipped honey keeper can control it, it is not the same with an imprudent walker approaching the hive. It attacks suddenly and stings without pity like all animals, which live normally facing danger to their existence.


Jolivet, P. 1991. Curiosités Entomologiques. Chabaud publs., Paris. Taylor, O. R. 2003. Neotropical African Bees. In Resh, V H. and Cardé, R. T. (eds.). Encyclopedia of Insects. Academic Press. Elsevier: 776-778.

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