Bees (Apiformes) represent a very important element influencing biodiversity; as active pollinators. They play a key role in maintaining the species richness of many plants [Jennersten et al., 1991; Kearns et al., 1998; Williams et al., 2001; Cussans et al., 2010]. These insects belong to specialised phytophages, pollinating over 70% of plant species [Richards, 1986]. They appeared in Earth’s history in the Cretaceous period along with angiosperm plants, and thus, are considered a relatively young insect group. They visit flowers for the collection of nectar and pollen, which they consume. So far, the occurrence of almost 16,000 bees has been determined worldwide. However, most scientists, including Michener [2007], assume that this number must be much higher, even above 30,000 species. Bees are a monophyletic group, which evolved from flower-visiting wasps, most probably the ancestors of the Sphecoidea. For example, Brothers (1975) and others link the Sphecoidea and bees in the Superfamily Apoidea, distinguishing two sections: the Spheciformes and the proper bees, also known as the Apiformes.
Michener [2007] distinguished 10 families within the Apiformes. Families occurring outside Europe include bees, whose dwelling is restricted to specific regions, for example, Australian (family Stenotritidae), Neoarctic (family Oxaeidae) and tropical areas (families Fidellidae and Ctenoplectridae). Similarly, as in Europe, representatives of 6 families occur in Poland: Colletidae, Andrenidae, Halictidae, Melittidae, Megachilidae and Apidae; the latter includes the Anthophoridae. The most well-known family is the Apidae, to which belongs the most ‘popular’ bee
Apiologists present a view that the oldest bees appeared in the early mid-Cretaceous, that is, about 125 million years ago. From that time onwards, they co-evolved with angiosperms. Till recently, it was considered that the oldest (preserved in amber) species is the worker
It is commonly considered that stingless bees (Meliponini) are derived from Africa. However, Kerr and Maule [1964] evidence a much higher diversity of this group in South and Central America; their wide distribution in the Miocene points to the origin of these bees in South America prior to the drowning of the Panama Isthmus in the early Eocene. Meliponini are a large group comprising about 500 species; in many tropical areas, these are the most common bees, playing the main role in pollinating native plants. According to Kerr and Maule [1964], the tropical areas of the New World contain 183 species, Africa – 32 species, Asia – 42, and Australia and New Guinea – 20 species of these insects. Due to the behavioural complexity, diversity and abundance, the Meliponini are presently the most commonly studied group in America. Results of these investigations are presented each year in seminars in Brazil, during which 40% from about 260 reports are focused on the Meliponini [Garófalo and Freitas, 2002].
Fifty-six genera were distinguished within the Meliponini, among which, three are most common. They include:
The common name of these insects – stingless bees – comes from the fact that bees of this group have highly reduced stingers, which are not used for defence. The workers of most species of stingless bees effectively defend themselves against enemies by roaming around the attacker’s body, stinging it with mandibles, pulling hair and clasping the mandibles within it. Release of this clutch requires detaching of the head from the insect’s body. The tropical
The size of these insects varies from 16 mm (in a worker of the genus
The superfamily Apoidea includes solitary, pre-social, properly social and parasite bees. All the stingless bees (Meliponini) belong to properly social bees, characterised by the following features: representatives of one species jointly nurse the offspring; there is a reproduction work subdivision, that is, a caste system; and at least two generations are capable of work for the whole family, that is, the offspring help the parents in raising their own siblings.
Meliponini usually form large families, reaching over 10,000 to even 100,000 or more individuals in number, and according to Michener [Michener,2007]are the most social bees. Similarly, as the honey bee
Similarly, as honey bees, Meliponini are characterised by stable polymorphism. Apart from a typical female form, the queen and a worker, which is a female with reduced reproductive organs, there is also a male drone. The social organisation within a single family includes one queen, several hundred drones and several thousand workers. The weight of the Meliponini queen is similar to that of a worker, but its thorax and cephalon are smaller, being equalized by the large abdomen. During its life, the queen feeds, copulates and lays eggs, never helping the workers in their everyday work with nest construction, raising the offspring and getting food [Kwapong et al., 2010].
Stingless bees are characterised by age polyethism. It is partly related with the activity of external glands. Division of labour among the workers depends on organised behaviour change taking place during the bee’s life [Sakagami, 1982]. Stingless bees possess an advanced system of chemical alarming and informing, enhanced by a modulated sound signal, that is, buzzing. The length of sound oscillations increases with the covered distance. Upon finding food, workers of Meliponini alarm the remaining bees very fast by smell traces [Lindauer and Kerr, 1960].This is a very effective method of information in tropical forests. After collecting food, on its way to the nest, the bee stops every few meters on plants or on the ground, leaving a drop of secretion from its mandible glands. The smell traces of stingless bees are polarised so that larger amounts of the smelling substance are located closer to the food source. Smell traces of the Meliponini are far more advanced than the honeybee’s dance (
Families of stingless bees can live perennially and reproduce by swarming. The life cycle begins when scout bees, probably aroused by high density in the old nest, begin to find a locality for a new nest. When the new locality is chosen, the workers seal all openings around the fracture in the ground and construct a nest entrance. At first, the building material is taken from the old nest. The workers collect beeswax in baskets located on the third pair of legs, and carry honey and pollen as fluid suspension in their goitres. At the same time, groups of males gather around the new nest. The new queen raised by the workers lives in the old nest for some time with the mother queen. Next, the new queen flies to the new nest alone or surrounded by a group of bees; soon, it performs the mating dance, which, for example, in
When comparing the reproduction of stingless bees (Meliponini) and honeybees (
The nest construction in the Meliponini is complex, characterised by a variable structure, and thus, suitable for evolutionary interpretation. Most species nest in various natural cavities in the ground, hollow trunks and tree branches, dead wood, abandoned ant and termite nests, and animal burrows, fractures in stone walls or caves. The species
In Meliponini, the construction of nest entrances also depends on the species. Some stingless bees construct simple nest entrances, whereas other build copula-like entrances in the form of rosettes (e.g.,
In the simplest case, the nest of stingless bees resembles the nest of bumblebees (
In a
Larval cells in which single individuals develop are surrounded by a soft beeswax cover (involucrum). Its role is to maintain a stable temperature in the nest. The involucrum is composed of several sheets and the bees move around in free spaces.
Larval cells and pots with honey and pollen are protected by an external, very thick and hard cover (bitumen) composed of propolis, hard beeswax, often plant substances, mud and so on. The cover may be multi-layered, with the bees moving around in the free spaces.
In underground nests, for example,
The ability of settling of some wild bees in artificial nests, that is, nest traps, was used in artificial cultivation for economic use. Clay and wooden traps are usually situated near human dwellings and are found in many parts of the worlds, for example, Borneo, Mexico or Indonesia.
Plant reproduction by pollination, including crops, forest trees, bushes and herbs is indispensable for further existence of an ecosystem; bees of various species play a crucial role in this process, which results in the quantity and quality of fruit and seeds in over 70% of flowering plants. Stingless bees play a key role in pollinating native flora in tropical areas. A plant species from the orchid group – vanilla (the most valuable spice after saffron) – is pollinated in Mexico exclusively by stingless bees from the genera
Honey produced by stingless bees is aromatic, sweet-sour in taste with a fruity tint. It contains more water (about 20-35%) and is more liquid than the honey produced by honeybees [Vit et al., 2004].In the Yucatan Peninsula lives the bee
propolis, which has been examined and proven to be effective in the treatment of many health problems, that is, infections and wound healing, and has antibiotic properties;
pollen, which is rich in vitamins, proteins and mineral components, and is used in the production of many cosmetics;
beeswax is used in the production of numerous industrial products and in pharmaceutics.
All the presented specific features of the behaviour of bees from the tribe Meliponini clearly indicate that these represent insects at the highest level of social evolution, even exceeding that of honeybees. It is commonly assumed that the social organisation of these insects developed after the separation of the ancestors of the present-day tribes of Meliponini and Apini. Their role in plant pollination indicates high economic significance of these tropical insects.