Invertebrates
Bee
Anthophila · also called bees
A bee is a wasp that stopped hunting. More than 100 million years ago, one lineage of predatory wasps began feeding its young on pollen instead of paralysed insects, grew branched hairs to carry the load, and became the group that now pollinates most of the flowering plants on Earth — and about a third of what humans eat.
Overview
Bees are the clade Anthophila, around 20,000 species, on every continent except Antarctica. All feed on pollen and nectar and take no animal food. Despite the popular image, the great majority are solitary — a single female provisioning a small nest — with the familiar social honeybees and bumblebees a small, unusual minority.
Solitary by default
A solitary mason, leafcutter, or mining bee female builds a few cells in a hollow stem or a burrow, stocks each with pollen and nectar, lays an egg, seals it, and moves on. No workers, no honey, no hive, and rarely any sting worth noticing. Only the honeybees and stingless bees store honey in quantity.
Senses and signals
Bees see ultraviolet, blue, and green but not red, and many flowers carry UV “nectar guides” invisible to us. A returning honeybee scout runs a waggle dance on the comb whose angle encodes the direction of food relative to the sun and whose length encodes the distance — a rare symbolic communication system.
The pollination service
Around 75 per cent of leading food crops benefit from animal pollination, most of it by bees — almonds, apples, blueberries, melons, coffee, cocoa — worth hundreds of billions of dollars a year.
Status
Bees as a group are Not Evaluated, with a decreasing trend. The honeybee is not endangered as a species, but managed hives suffer heavy losses to the varroa mite and its viruses, and many wild bumblebees and solitary bees are in long-term decline from lost flower-rich habitat, pesticides, and disease.
Bee: common questions
Do all bees make honey and live in hives?
No, and this is the biggest misunderstanding about bees. Only a small number of highly social species store honey in quantity, chiefly the handful of honeybee species and, in smaller amounts, the tropical stingless bees. Bumblebees keep only tiny nectar pots and colonies that last a single season. The vast majority of bee species, around 90 per cent, are solitary. A solitary female mason bee, leafcutter bee, or mining bee builds a nest of a few cells in a hollow stem, a beetle hole, or a burrow, stocks each cell with a lump of pollen and nectar, lays an egg, seals it, and moves on, with no colony, no honey, and no hive to defend.
What is the difference between a bee and a wasp?
Bees are a specialised branch of the wasps that switched to a plant diet, so the split is real but recent in evolutionary terms. The practical differences follow from that diet. Bees are usually hairier, often with branched hairs that trap pollen, and many have broad hind legs or a brush under the abdomen for carrying it, while wasps are typically more slender and smooth with a narrow waist. Bees feed their young pollen and nectar; most wasps feed theirs on insects or spiders. Bees are important pollinators, whereas wasps are mainly predators and scavengers that help control pest insects. Both can sting, but a bee gains nothing from stinging and most solitary bees rarely do.
Why are bees in trouble, and is it just honeybees?
The honeybee and the wild bees face overlapping but different problems. Managed honeybee colonies suffer heavy losses in many years, driven largely by the parasitic varroa mite and the viruses it spreads, alongside pesticide exposure and the poor nutrition of landscapes with few flowers. As a species, though, the honeybee is not endangered, since beekeepers can breed replacements. The deeper concern is wild bees, especially bumblebees and pollen-specialist solitary bees, which are declining across Europe and North America mainly because flower-rich grassland, hedgerows, and nesting habitat have been lost to intensive agriculture and development, with pesticides and disease from managed hives adding to the pressure.
How do bees help plants, and how do plants reward them?
It is a trade. A bee visits a flower to collect nectar, a sugar solution that fuels its flight, and pollen, which supplies protein for its larvae. As it moves over the flower, pollen grains stick to its branched body hairs, and some are brushed onto the female parts of the next flower of the same species the bee visits, fertilising it. The plant gets its pollen carried precisely to another plant of its kind, far more efficiently than by wind, and in return provides the food. Many flowers have evolved shapes, colours, ultraviolet patterns, and scents specifically to attract bees and to place pollen where it will contact them.