Bees belong to the order Hymenoptera, along with other insects such as ants and wasps. Currently, around 20,000 species of bees have been described worldwide.
Characteristics of bees
The close kinship between bees and wasps sometimes makes it difficult to tell them apart. There are bees such as those of the genus Nomada, which are virtually hairless, slender and have wasp-like colour patterns.
The main characteristic that distinguishes bees is the presence of branched hairs. Although wasps can also have hairs, they are simple. This difference is difficult to see with the naked eye and usually requires a microscope or a magnifying glass to observe it.
Other characteristic features of bees, although shared with other hymenopterans, are the presence of stinger and the haplodiploidy. The sting of bees evolved from the ovipositor, an organ used by the females of many insects to lay eggs. Through evolution, this organ transformed into a sharp structure for defence, capable of injecting venom. However, some bees, known as stingless bees, have this organ so reduced that they cannot use it for defence.
On the other hand, haplodiploidy is a sex determination system based on the number of copies of each chromosome. Female bees have two copies of each chromosome (like humans), while males have only one. This means that females hatch from fertilised eggs, with one copy of the chromosome from each parent, whereas males hatch from unfertilised eggsand only have the mother's genetic material.
In terms of their life cycle, bees are holometabolous,insects, i.e. they are born as larvae and undergo a complete metamorphosis to become adults.
Although we tend to associate bees with the best known species, Apis mellifera, most species do not produce honey and are solitary. In these species, each female builds her own nest in which she lays her eggs and stores food for her brood. There are also cuckoo bees, which do not collect food for their offspring. Instead, they invade the nests of other bees and lay their eggs inside. Their larvae then consume the food that the host female or females collect for the offspring of their own nest.
Where do they live?
The greatest diversity of bee species can be found in dry areas with high solar radiation. The regions with the highest species richness are southwestern United States, the Mediterranean Basin, Nepal, some areas of the Andes, the southern Amazon Basin and South Africa.
Bees can live in many different environments as long as they have access to floral resources and nesting sites. They are found in a variety of natural, semi-natural and urban habitats, such as grasslands, woodland margins and clearings, roadsides, crops, gardens, scrubland and wetlands.
What do they eat?
Bees feed mainly on pollen and nectarduring both their larval and adult stages. This is one of the most notable differences with wasps, which are primarily carnivorous.
Some species also collect floral oils to feed their larvae. In addition, within the Meliponini group of tropical bees (the so-called stingless bees), there are a few species known as "vulture bees", which can consume pollen and nectar, but prefer to feed on rotting meat of animals such as snakes and lizards.
Ecological importance
Bees play a fundamental role in ecosystems as pollinators,They are considered to be the most efficient group of animals for this purpose. However, their ecological importance is not limited to pollination.
Most bees nest in the soil, which contributes to increasing soil porosity, improving aeration, infiltration of water and facilitating the root growth of plants. In addition, bees bring into their nests materials such as pollen, resins, leaf fragments and their own waste (faeces and corpses), which provide organic matter to the ground.
Finally, scavenger bee species help in the decomposition of animal remains by facilitating nutrient recycling in ecosystems.
If you want to learn more about bees or get started with the challenge of identifying bee species, visit our section on bee bibliography.
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