Stingless bees, sometimes called stingless honey bees or simply meliponines, are a large group of bees (about 550 described species), comprising the tribe Meliponini (or subtribe Meliponina according to other authors). They belong in the family Apidae, and are closely related to common honey bees, carpenter bees, orchid bees, and bumblebees. Meliponines have stingers, but they are highly reduced and cannot be used for defense, though these bees exhibit other defensive behaviors and mechanisms. Meliponines are not the only type of bee incapable of stinging: all male bees and many female bees of several other families, such as Andrenidae, also cannot sting. Some stingless bees have powerful mandibles and can inflict painful bites.
Geographical distribution
Stingless bees can be found in most tropical or subtropical regions of the world, such as Australia, Africa, Southeast Asia, and tropical America. The majority of native eusocial bees of Central and South America are stingless bees, although only a few of them produce honey on a scale such that they are farmed by humans. They are also quite diverse in Africa, including Madagascar, and are farmed there also; meliponine honey is prized as a medicine in many African communities, as well as in South America.
The evolutionary origin of the Meliponini is Neotropical. Observing contemporary species richness shows that it remains highest in the Neotropics.
Behaviour
Being tropical, stingless bees are active all year round, although they are less active in cooler weather, with some species presenting diapause. Unlike other eusocial bees, they do not sting, but will defend by biting if their nest is disturbed. In addition, a few (in the genus Oxytrigona) have mandibular secretions, including formic acid, that cause painful blisters. Despite their lack of a sting, stingless bees, being eusocial, may have very large colonies made formidable by the number of defenders.
Hives
Stingless bees usually nest in hollow trunks, tree branches, underground cavities, termite nests or rock crevices, but they have also been encountered in wall cavities, old rubbish bins, water meters, and storage drums. Many beekeepers keep the bees in their original log hive or transfer them to a wooden box, as this makes controlling the hive easier. Some beekeepers put them in bamboos, flowerpots, coconut shells, and other recycling containers such as a water jug, a broken guitar, and other safe and closed containers.
The bees store pollen and honey in large, egg-shaped pots made of beeswax (typically) mixed with various types of plant resin; this combination is sometimes referred to as "cerumen" (which is, incidentally, the medical term for earwax). These pots are often arranged around a central set of horizontal brood combs, wherein the larvae are housed. When the young worker bees emerge from their cells, they tend to initially remain inside the hive, performing different jobs. As workers age, they become guards or foragers. Unlike the larvae of honey bees and many social wasps, meliponine larvae are not actively fed by adults (progressive provisioning). Pollen and nectar are placed in a cell, within which an egg is laid, and the cell is sealed until the adult bee emerges after pupation (mass provisioning). At any one time, hives can contain 300–80,000 workers, depending on species.
The remainder of the nest cavity, including the entrance tubes, is generally lined with of a mixture of secreted wax, plant resins ("propolis"), and other substances such as animal feces.
Role differentiation
In a simplified sense, the sex of each bee depends on the number of chromosomes it receives. Female bees have two sets of chromosomes (diploid)—one set from the queen and another from one of the male bees or drones. Drones have only one set of chromosomes (haploid), and are the result of unfertilized eggs, though inbreeding can result in diploid drones.