Stingless bee

Stingless bees, sometimes called stingless honey bees or simply meliponines, are a large group of bees (about 500 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 'stingless' bee; all male bees and many female bees of several other families, such as Andrenidae, also cannot sting. 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. 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. 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. 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. Unlike true honey bees, whose female bees may become workers or queens strictly depending on what kind of food they receive as larvae (queens are fed royal jelly and workers are fed pollen), the caste system in meliponines is variable, and commonly based simply on the amount of pollen consumed; larger amounts of pollen yield queens in the genus Melipona. Also, a genetic component occurs, however, and as much as 25% (typically 5–14%) of the female brood may be queens. Queen cells in the former case can be distinguished from others by their larger size, as they are stocked with more pollen, but in the latter case, the cells are identical to worker cells, and scattered among the worker brood. When the new queens emerge, they typically leave to mate, and most die. New nests are not established by swarms, but by a procession of workers that gradually construct a new nest at a secondary location. The nest is then joined by a newly mated queen, at which point many workers take up permanent residence and help the new queen raise her own workers. If a ruling queen is herself weak or dying, then a new queen can replace her. For Plebeia quadripunctata, although fewer than 1% of female worker cells produce dwarf queens, they comprise six of seven queen bees, and one of five proceed to head colonies of their own. They are reproductively active, but less fecund than large queens. While the existence of a soldier caste is well known in ants and termites, the phenomenon was unknown among bees until 2012, when some stingless bees were found to have a similar caste of defensive specialists that help guard the nest entrance against intruders; to date, at least 10 species have been documented to possess such 'soldiers', including Tetragonisca angustula, T. fiebrigi, and Frieseomelitta longipes, with the guards not only larger, but also sometimes a different color from ordinary workers.