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Chapter 1 Honeybees of the Genus apis
A. The dwarf honeybee Apis florea
B. The giant honeybee Apis dorsata
C. The oriental honeybee Apis cerana
D. The common, or european, honeybee Apis
mellifera
E. Honeybee species kept by man
Bees are insects of the Order Hymenoptera which feed on pollen and nectar. They constitute a group of about 20 000 species throughout the world, known taxonomically as the Superfamily Apoidea. Honeybees of the genus Apis belong to the family Apidae, a sub-group of this superfamily. Although the question of how many honeybee species exist is still debated among taxonomists, at least four species are commonly recognized: the dwarf, or midget, bee Apis florea, the giant, or rock, bee Apis dorsata, the oriental (Indian, Chinese, Japanese, etc.) bee Apis cerana, and the common (European, African, etc.) honeybee Apis mellifera. The existence of another giant tree, Apis laboriosa, has recently been confirmed from Nepal, but little is known about its biology.
All honeybee species are eusocial insects, that is to say that they engage in favourable social activity. A colony of honeybees consists of a queen, several thousand workers, and at certain seasons of the year - a few hundred drones. Among the members of the colony there is division of labour and specialization in the performance of biological functions.
The architectural design of the comb of all honeybee species is essentially similar: it consists of adjoining hexagonal cells made of wax secreted by the workers' wax glands. The bees use these cells to rear their brood and to store their food. The general utilization of comb space is also similar among the species: honey is stored in the upper part of the comb, with, beneath it, rows of pollen-storage cells, worker-brood cells, and drone-brood cells, in that order. The groundnut-shaped queen cells are normally built at the lower edge of the comb.
As an inherited behaviour characteristic, all honeybee colonies tend to store a certain amount of honey and pollen as their food reserve. The quantity of food stored depends upon several factors, including the seasonal availability of forage, the worker population of the colony and its rate of reproduction, the capacity of the nest, etc. Another important inherited behaviour characteristic lies in the colony's natural site of comb construction: whereas some Apis species build singlecomb nests in the open, others build multiple-comb nests in dark cavities.
A. The dwarf honeybee Apis florea
The distribution area of A. florea is generally confined to warm climates. In the west, the species is present in the warmer parts of Oman, Iran and Pakistan, through the Indian sub-continent and Sri Lanka. It is found as far east as Indonesia, but its primary distribution centre is southeast Asia. Rarely found at altitudes above 1500 m, the bee is absent north of the Himalayas. It is frequently found in tropical forests, in woods and even in farming areas. In southeast Asia it is not rare to find a nest of A. florea in a village.
As its name implies, the dwarf honeybee is the smallest species of honeybee, troth In the body size of its workers and in the size of its nest. A nest of A. florea consists of a single comb, whose upper part expands to form a crest that surrounds the branch or other object from which the comb is suspended. Dwarf honeybees nest in the open, but not without camouflage: most nests are hung from slender branches of trees or shrubs covered with relatively dense foliage, usually from 1 to 8 metres above the ground. In Oman, where A. florea nests are frequently found in caves, such combs are without crests.
Combs of the dwarf honeybee are well covered with layers of workers clinging to each other' often three or four deep. About three quarters of the colony's worker population are employed in forming this living protective curtain of bees. When disturbed, this curtain shows a "shimmering" movement, the individual trees shaking their abdomens from side to side in a synchronous manner; at the same time, a hissing sound is released. If the colony is further disturbed, the worker trees raise their abdomens and take off from the curtain to attack the intruder.
The section of comb surrounding the support (in Fig. 1/1, a small tree branch) consists of adjoining honey-storage cells that form a crest, from whose inroad curved surface the trees take off and on which they land. The communication dance by scouts, announcing the discovery of a food source, also takes place on this platform. Adjacent to the rows of honey-storage cells is the section of comb which the workers use for storing pollen. Beneath this band of pollen-storage cells is the area where the worker brood is reared. Prior to the swarming season, drone-brood cells are added, adjoining the lower rows of the worker-brood cells. When a colony loses its queen, emergency queen-cells are built from normal cells containing young worker larvae.
To ward off ant attacks, the workers coat both ends of the nest support with sticky strips of propolis, or "plant gum", from 2.5 to 4 cm wide. A. florea is the only honeybee that uses this defensive technique.
During the season when there is an ample supply of nectar and honey, populous colonies of the dwarf honeybee send out multiple reproductive swarms. In addition, colonies of this tree have a high degree of mobility. Disturbance by natural enemies, exposure to inclement weather and scarcity of forage are among the major causes of colonies absconding.
In comparison with other honeybee species, the amount of honey that A. florea workers will store in their nests is small, usually not exceeding several hundred grams per colony. In some parts of Asla, the rural people have devised a scheme for harvesting this honey. First, nests or the bees are transferred from their natural sites to the village, and then, using twine and two short twigs, the nest is clamped and attached to a small branch of a tree. The upper part of the comb, containing the honey, is cut out, and the honey is squeezed out from it. A period of about six to eight weeks is allowed for the bees to repair the comb and replenish it with honey, and then it is harvested again. This method is not always reliable, however, because most colonies will abscond either shortly after their transfer to the new site or after the first or second harvest has taken place.
Where nests of A. florea are abundant, several rural families can subsist on the income generated from beehunting alone. Although the practice appears ecologically destructive, particularly insofar as it reduces a valuable population of natural pollinators, it does not always destroy the colony being hunted. Workers and laying queens of the dwarf honeybee are able to respond to nest predation quickly. The entire colony, accompanied by a laying queen, can fly several meters away to regroup, and later abscond. Some absconding colonies are able to survive to build their new combs in a nearby area.
B. The giant honeybee Apis dorsata
The distribution area of the giant honeybee is similar to that of the dwarf honeybee: it occurs from Pakistan (and, perhaps, parts of southern Afghanistan) in the west, through the Indian subcontinent and Sri Lanka to Indonesia and parts of the Philippines in the east. Its north-south distribution ranges from the southern part of China to Indonesia; it is found neither in New Guinea nor in Australia.
The giant honeybees of Nepal and the Himalayas have recently been reclassified as belonging to another species of Apis, A. laboriosa. It is not yet c]ear whether the giant honeybees of Sikkim and Assam in northern India, western Yunan Province in China, and northern Burma should he classified as A. dorsata or as A. laboriosa, but in the present state of our knowledge, it is safe to consider that all the giant trees constitute a single taxonomic identity. Although minor variations in anatomical, physiological and behavioral characteristics exist among the different geographical races of the giant honeybees, they are essentially similar in all their major biological attributes.
The giant honeybees are found predominantly in or near forests, although at times nests may be observed in towns near forest areas. The bee shares the openair, single-comb nesting habits of Apis florea, suspending its nest from the under surface of its support, such as a tree limb or cliff. In general, A. dorsata tends to nest high in the air, usually from 3 to 25 meters above the gound. In tropical forests in Thailand, many nests are suspended in Dipterocarpus trees from 12 to 25 meters high: this tree is probably preferred as a relatively safe nesting site because its smooth bark and its trunk rising for 4 to 5 meters before branching out make it very difficult of access to terrestrial predators. Nonetheless, about three-quarters of the worker population of a colony of giant honeybees is engaged in colony defence, forming a protective curtain three to four trees thick in the same way as Apis florea. While birds are common predators of A. dorsata, the workers' large body size protects them reasonably well against ant invasion, so that the sticky bands of propolis characterizing the nests of the dwarf honeybee are not found surrounding the nests of A. dorsata, nor are the nests hidden by dense foliage. Nests of A. dorsata may occur singly or in groups; it is not uncommon to find 10-20 nests in a single tall tree, known locally as a "bee tree". In India and Thailand, tree trees harbouring more than 100 nests are occasionally seen in or near the tropical forest.
The single-comb nest, which does not have the crest of honey-storage cells typical of A. florea nests, may at times be as much as one meter in width. The organization of the comb is similar to that in the other honeybee species: honey storage at the top, followed by pollen storage, worker brood and drone brood. At the lower part of the nest is the colony's active area, known as the "mouth", where workers take off and land, and where communication dances by scouts, announcing the discovery of food sources, take place. This dance takes place on the vertical surface of the comb, and during its progress, the bees must have a clear view of the sky to observe the exact location of the sun. Workers of A. dorsata are however able to fly at night, when the light of the moon is adequate.
In many places, the arrival of A. dorsata colonies is an annual event, occurring at the end of the rainy season or at the beginning of the dry season, when several species of nectaryielding plants are in bloom. This phenomenon leads to speculation that A. dorsata has a fixed pattern in its annual migratory route. Most professional bee-hunters know when and where the trees are to arrive, but they wait patiently until the end of the honey-flow period before taking down the nests. Observations in northern Thailand indicate that if the nests are left undisturbed, the colonies will eventually abscond or migrate when their food reserves have been depleted, usually at the end of the summer months. By the beginning of the rainy season, A. dorsata colonies are found deep in the lush jungles.
A. dorsata is well known for its viciousness when its nest is disturbed: the mass of defending workers can pursue attackers over long distances, sometimes more than 100 meters. Notwithstanding its ferocity, however, this tree's honey is highly prized locally, in some places commanding the best prices in local markets,
Nests of the giant honeybee have been hunted by man since antiquity, and today, organized bee hunting exists in many parts of Asia. In Thailand, bee-hunters must pay fees for permits to hunt the bee in state forests, and landowners possessing bee trees sell annual or biennial rights to hunt nests from such trees.
Some professional bee-hunters prefer to work at night. Smoke is used to pacify the bees, which are then scraped from the comb. The nest is cut and placed in a cloth bag, which is lowered to an assistant on the ground. This method does not result in all colonies being killed: about a fourth of the colonies in a bee tree that has been worked over are able to reconstruct their nests.
The recent intensification of bee hunting has caused an alarm in several Asian countries. There is general concern that the total number of A. dorsata nests all over Asia may be on the verge of declining, partly due to shrinking forest areas, the use of toxic pesticides in foraging farm lands, and bee hunting.
C. The oriental honeybee Apis cerana
For ages, colonies of the oriental honeybee Apis cerana have provided mankind with honey and beeswax, as well as furnishing invaluable service in the pollination of agricultural crops. This bee's range of distribution is far greater than those of A. florea and A. dorsata: it is found throughout the tropical, sub-tropical and temperate zones of Asia, occurring in the Indian sub-continent and Sri Lanka in the west, through southeast Asia, to Indonesia and the Philippines in the east. Further north, it is found in the southern USSR and China, through the Korean peninsula, to Japan. This wide range has led to important variations among the bee's geographical races: particularly between the tropical and temperate races, there are wide differences in workers' body size, nest size, colony population and swarming and absconding behaviour, The temperate and sub-tropical races appear to store greater quantities of food than the tropical races, which in turn are more mobile than the former, tending to swarm, abscond and migrate quite frequently.
In the wild, the oriental honeybees construct their multiple-comb nests in dark enclosures such as caves, rock cavities and hollow tree trunks. The normal nesting site is, in general, close to the ground, not more than 4-5 meters high. The bees' habit of nesting in the dark enables man to keep them in specially constructed vessels, and for thousands of years Apis cerana has been kept in various kinds of hives, i.e. clay pots, logs, boxes, wall openings, etc. Despite the relatively recent introduction of movable-frame hives, colonies of Apis cerana kept in traditional hives are still a common sight in the villages of most Asian countries. As a result, the feral nests of the oriental honeybee in tropical Asia sustain fewer casualities in being hunted by man than those of the dwarf and giant honeybees.
The several combs of an A. cerana colony are built parallel to each other, and a uniform distance known as the "bee space" is respected between them. The body size of the workers of this tree is much smaller than that of the A. dorsata workers, and its brood comb consists of cells of two sizes: smaller for the worker brood and larger for the drone brood. The queen cells are built on the lower edge of the comb. As in the other Apis species, honey is stored in the upper part of the combs, but also in the outer combs, adjacent to the hive walls.
Following the invention of the movable-frame hive for the European honeybee about a century ago, traditional beekeeping with A. cerana has been partially replaced by this modern method in several Asian countries, and at the same time attempts have been made - with varying degrees of success - to improve hiving techniques and colony management.
D. The common, or european, honeybee Apis mellifera
There are many geographical races of the common honeybee Apis mellifera, distributed widely throughout Europe, Africa, and parts of western Asia, as well as in the Americas. All these races display similarities in their basic biological attributes, e.g. the construction of multiple-comb nests in dark cavities, colony social organization and division of labour, etc,
In the wild, the natural nesting sites of A. mellifera are similar to those of A. cerana: caves, rock cavities and hollow trees. The nests are composed of multiple combs, parallel to each other, with a relatively uniform bee space. The nest usually has a single entrance. The temperate races prefer nest cavities of about 45 Litres in volume and avoid those smaller than 10, or larger than 100, litres. Colonies of the European races are composed of relatively large populations, usually between 15 000 and 60 000.
Many feral nests of A. mellifera in the northeastern forests of the United States have been reported to store 25 to 30 kg of honey per colony, and even more, during the nectar-flow spring season, and properly managed, commercially operated, colonies yield much more.
Anthropomorphically speaking, this behaviour of the temperate races is obviously an evolutionary advantage: without it, the colony faces starvation during the cold winter months, when food is not naturally available and the temperature is too low to permit flight activity. The shortage of natural forage and the cold temperatures prevailing from late autumn until early spring appear to play an important role in exercising rigid natural-selection pressures on the colonies. As a result, both feral and hived colonies of temperate-zone A. mellifera are less likely to abscond than the tropical races.
The past three centuries have seen the introduction of the common honeybee to all the habitable continents. Outside Asia, beekeeping with A. mellifera constitutes an integral part of modern agricultural systems, furnishing crop pollination services as well as honey and beeswax. Although this bee is one of the most studied animals, many aspects of its biology being fully known, efforts over the past few decades to introduce A. mellifera into Asia have encountered a number of problems, such as the inter-species transmission of bee pests and diseases.
But successes have been reported from several Asian countries as regards the commercial viability and the likelihood of a profitable economic return of beekeeping with A. mellifera. It appears that the adaptability of the bees, appropriate beekeeping technology, better understanding of forage ecology and socio-economic suitability are among the most important factors underlying the further development of beekeeping with the common honeybee in Asia.
E. Honeybee species kept by man
Among the four commonly-recognized species of Apis, only A. cerana and A. mellifera are kept commercially by man. Behavioural limitations of the dwarf and giant honeybees, particularly their practice of open-air nesting, prevents their being kept in man-made hives for reasonably long periods, while hiving colonies in specially-constructed containers is essential in that it enables the colonies to be manipulated.
In many parts of the world, including several countries in Asia, commercial beekeeping depends on moving the honeybee colonies to places where forage is abundant at certain periods of the year. Such migratory beekeeping often calls for the colonies to be moved several times a year, over distances which may range from a few kilometres to several hundred kilometres from the home base. This approach is practicable only when the colonies are in movable-frame hives, which can he transported without danger to the hives or the colonies. From the practical standpoint, therefore, beekeeping can he A dependable agricultural occupation only when the beekeeper can determine and control the number of hives he owns.
Generally speaking, there are two possible approaches to the development of commercial beekeeping in Asia: the introduction of modern beekeeping with A. mellifera or the improvement of existing techniques for using A. cerana. Notwithstanding the difficulties involved in establishing new apiaries of the introduced colonies and in developing colony management techniques suitable to local conditions, A. mellifera colonies are generally more productive than those of A. cerana where forage is abundant, and the development of beekeeping with A. mellifera in Japan, the Republic of Korea, China and northern Thailand is based on this finding.
On the other hand, where forage is available only marginally, colonies of A. cerana survive better and can produce with lower management inputs than colonies of A. mellifera. It is the absconding behaviour of most, if not all, tropical races of A. cerana that creates a major obstacle to the development of beekeeping with this bee in rural areas in southern Asia. Since this behaviour is apparently triggered, at least to some extent, by an unfavourable hive environment, proper colony management may be able to provide at least a partial solution to this problem.
Thus, only through systematic research and development activities carried out locally is it possible to judge which of the two approaches to apicultural development should be adopted to suit the socio-economic situation, the vegetation pattern and the climatic conditions of each locality.