Distribution

1. Apis mellifera throughout the world. Apis cerana, dorsata and florea in southern Asia and Southeast Asia. Apis labriosae in Nepal, northern India and Yunnan. 
2. Most widespread in temperate and cool zones of Europe, North America and Asia; a few species in South America, north Africa and in mountainous regions in India and Southeast Asia.

Biology

Over 27,000 species of bees (Apoidea) have been described so far. As they are members of the Aculeata all of them possess a sting apparatus associated with venom glands (see General information on hymenopterans: Morphological characteristics and venom apparatus). In stingless bees (Meliponini) the sting has regressed, but the glands are still viable; like stingless ants they bite fiercely when threatened and smear secretion from the abdominal glands into the wound. The sting of honey bees (Apis spp.) has a distinctive feature, in that the lancets (Fig. 4.45) have comparatively large barbs that project beyond the edge of the sting. This means that the sting cannot be drawn out of the elastic skin of mammals and humans. When the bee flies away the whole venom apparatus is torn out of its abdomen and the bee dies as a consequence. Venom continues to be reflexively pumped out into the skin from the venom apparatus left behind. Such a phenomenon, which is highly unfavourable for the individual animal, is only conceivable in the context of the extremely high degree of socialisation among honey bees, where protection of the colony is far more important than the individual animal.

Following honey bee stings, the sting should be carefully removed from the skin – if possible using tweezers – to avoid squeezing more venom from the attached venom sac into the wound.

In contrast to the predatory, social wasps, bees and their offspring feed only from pollen and nectar. Their body and legs are usually covered in dense hairs to facilitate pollen collection. As pollinators of many flowering plants the Apidae in particular play an extremely important role in agriculture. Cultivation of a considerable number of fruits, vegetables and forage crops would be inconceivable without bees.

Most species are solitary and build their nests on the ground or in fallen trees. Honey bees, stingless bees and, to a lesser extent, also bumble bees build complex social (eusocial) colonies (see General information on hymenopterans: Social organisation).

Bombus spp.: bumble bee colonies are generally small, usually consisting of only several dozen individuals. The queen is only slightly different in appearance from the workers, and the domestic organisation is less clearly defined than it is in honey bees or stingless bees. Only the queen hibernates, and in spring she establishes a new colony on her own, after finding a suitable place in or on the ground (often in abandoned rodent burrows).

Apis spp.: honey bee colonies consist of several thousand individuals, some of which hibernate with the queen, who is considerably larger than the other bees. The highly complex organisation and communication within the colony are regulated via specific pheromones (chemical messenger substances) or behavioural patterns. These interactions become obvious if a victim is stung close to a bee colony, as the stings of a few bees release alarm pheromones that rapidly attract other bees and induce defensive behaviour.

Only A. mellifera and A. cerana build their nests in the dark and can thus be kept in beehives for making honey or for pollination of fruit trees and other crops. In the course of domestication of bees in Europe, various races of A. mellifera were bred, which were then introduced to almost all countries throughout the world.

Fig. 4.46 Apis mellifera

Risk

See also General information on hymenopterans: Epidemiology.

In contrast to wasps, bees only use their stings for defence. However, many of the solitary bees are very reluctant to use their stings even when greatly provoked.

Halictidae, which are attracted by human sweat, or the tropical Mellitidae can be very persistent, and multiple stings or bites are not uncommon. However, the results are more unpleasant than dangerous. Envenoming caused by bumble bees, which are reluctant to sting, only rarely takes a dangerous course.

Among the Apoidea, the honey bees possess by far the greatest significance for humans and animals. Most important of all are the cosmopolitan A. mellifera, which, because of their domestication, often live in close proximity to humans.

The Africanised honey bee A. mellifera scutellata is considered particularly aggressive. They were introduced to Brazil in 1956 from where escaped colonies spread extremely rapidly throughout South America and moved closer and closer to the USA, reaching Mexico and southwest USA not long ago. Nonetheless their spread is limited by climatic factors, as they cannot hibernate in colder zones.

In South America A. m. scutellata represents a serious problem for humans and livestock. Even slight disturbances close to a nest can put the bees on alert and trigger an explosive chain reaction, so that sometimes animals and humans will be stung by hundreds or even thousands of bees. Intruders may be pursued for a distance of 200–1,000 m, and the average time it takes for an angry colony to settle again is approx. 30 min. In comparison, Italian honey bees will pursue an invader over a radius of only about 20 m and take only around 3 min to settle again after going on the alert (Michener 1975).

Literature (biological)

Akre and Reed 1984, Fletcher 1978, Gould and Gould 1988, Michener 1975, 2000, O'Toole and Raw 1991, Taylor 1977, Winston 1994, Brothers 1999

Tree of life web project

Bee Phylogeny at Cornell University