Bees: A Complete Global Guide

There are approximately 20,000 described bee species worldwide, organised into seven families: Apidae, Halictidae, Andrenidae, Megachilidae, Colletidae, Melittidae, and Stenotritidae. Scientists estimate that undescribed species in tropical regions may push the true total significantly higher. They inhabit every continent except Antarctica.

The UK is home to approximately 270 native bee species. These include 24 bumblebee species, around 245 species of solitary bee (mining bees, mason bees, leafcutter bees, plasterer bees, and cuckoo bees), and a single managed honeybee species, Apis mellifera. Many solitary species are under-recorded, particularly outside southern England.

Bumblebees are larger, rounder, and heavily furred. They live in annual colonies of 50 to 400 individuals that die each winter, with only mated queens surviving. Honeybees are smaller and leaner, live in perennial colonies of 20,000 to 80,000, and survive winter as a full colony by consuming stored honey. Only honeybees produce honey in commercially significant quantities. Both are members of the family Apidae.

Bees are the world's primary pollinators. Around 75% of globally important food crop species depend on animal pollinators to produce fruit, seed, or viable harvest. Without bees, crops including almonds, tomatoes, strawberries, coffee, cocoa, avocados, blueberries, and courgettes would fail at scale. The economic value of insect pollination to global agriculture is estimated at over 150 billion euros annually.

Klein et al. (2007), the most comprehensive peer-reviewed assessment of crop-pollinator relationships, found that 87 of 115 globally important food crops benefit from animal pollination. This represents approximately 35% of global food production by volume and up to 75% of crop species. Calorie staples like wheat, rice, and maize are wind-pollinated and largely unaffected, but most fruits, vegetables, nuts, and flavouring crops depend on bees.

Wallace's Giant Bee, Megachile pluto, is the world's largest bee. Named after Alfred Russel Wallace, who discovered it in the Indonesian island of Bacan in 1858, females reach up to 38mm in length with a wingspan of 63mm. It was feared extinct for over a century before being rediscovered alive in North Maluku, Indonesia in 2019. It nests inside active termite mounds.

Perdita minima, a member of the family Andrenidae, is the world's smallest bee at approximately 2mm in length. It is native to the desert southwest of the United States. Despite its size, it is a functional pollinator, specialising on small desert flowers. It is so small it can be easily overlooked in field surveys.

Many bee species are threatened. The IUCN Red List classifies over 700 bee species as threatened or near-threatened globally. In the UK, two species have become extinct in the 20th century and several more are critically scarce. The Great Yellow Bumblebee (Bombus distinguendus) has lost over 80% of its former UK range. Globally, wild bee populations have declined an estimated 30% over the past three decades due to habitat loss, pesticide exposure, disease, and climate change.

Buzz-pollination, or sonication, is a technique used by bumblebees and certain solitary bees to extract pollen from flowers whose anthers resist simple contact transfer. The bee grips the anther and vibrates its flight muscles at around 400 Hz, shaking the pollen loose. Tomatoes, aubergines, blueberries, and courgettes all require this process. Honeybees cannot perform sonication. It is one reason why wild bumblebee populations are irreplaceable even when managed honeybees are present.

Bees feed on nectar and pollen. Nectar, a sugar-rich solution produced by plant nectaries, provides energy. Pollen provides protein, fats, vitamins, and minerals for developing larvae. Adult bees consume nectar for flight energy, while larvae are fed a mixture of pollen and nectar (or in the case of honeybees, royal jelly for queens). The transformation of nectar into honey involves the addition of enzymes and the evaporation of water from around 80% moisture content down to below 18%.

Lifespan varies significantly by species and caste. Honeybee worker bees live 6 to 8 weeks in summer, or up to 6 months overwintering. Honeybee queens can live 3 to 5 years. Bumblebee workers live 2 to 6 weeks; queens live around a year including hibernation. Most solitary bees live 4 to 8 weeks as adults. The larval and pupal stages, inside sealed nest cells, can last from weeks to years depending on species.

Forager honeybees collect nectar and store it in their honey stomach. Back at the hive, they transfer it to house bees who chew it, adding enzymes including invertase (which breaks sucrose into fructose and glucose) and glucose oxidase (which produces hydrogen peroxide, giving honey its antimicrobial properties). The nectar is then deposited into honeycomb cells and fanned by thousands of bees to evaporate water. When moisture falls below 18%, cells are capped with wax and the honey is stable indefinitely. Raw honey, like ours, is extracted without heating to preserve these enzymes intact.