OUTLOOK BEES MEET OUR PRIME POLLINATORS Bees do far more than just make honey. Globally, the 25,000 or so bee species play a crucial part in crop production and in promoting biodiversity. By Julie Gould. TYPES OF BEE The honeybee (Apis mellifera) is the most widely studied bee, yet the approximately 10 species of honeybee comprise less than 0.05% of all known bee species. Apidae family: 5,811 species Includes honeybees, bumblebees, stingless bees, orchid bees, carpenter bees and many cuckoo bees. Halictidae: 4,401 species Includes many primitively social species as well as sweat bees, which suck perspiration from the skin of humans and animals. Megachilidae: 4,111 species Solitary bees, including leaf-cutter and mason bees (the females of which collect pollen with their abdomen instead of their legs). Andrenidae: 2,952 species Mining bees that are particularly common in temperate climates. 5,000 Colletidae: 2,595 species Estimated number of Mining and cavity-nesting bees, including plasterer and yellow-faced bees. unknown, undescribed Melittidae: 201 species bee species. The total A small family of mining bees, most of which visit particular owers. number of species is Stenotritidae: 21 species thought to be about A small family of mining bees endemic to Australia. 25,000. BIOLOGY Bees, a major group in the order Hymenoptera, evolved The largest known bee: In many species, males often have from wasps and have adapted to take advantage of the females of the Indonesian more colouration on their face than energy available from feeding on pollen and nectar. 50 Chalicodoma pluto can be do females, but there is little up to 39 mm long. dierence on the rest of their bodies. Honey stomach: stores nectar 40 A species of the during ight. Simple eyes: 63 MM WINGSPAN stingless vulture bee used to orientate (Trigona hyalinata) is bees towards almost all black. the Sun. 30 A worker honeybee is The North American The smallest about 14 mm Agapostemon splendens Millimetres 20 known bee is in length. is green and blue. the Australian Pollen comb: used by Quasihesma bees to brush pollen bee, which is Male valley carpenter 10 from their bodies. only 1.8 mm bees (Xylocopa long. varipuncta), found in Pollen basket: used by North America, are bright yellow all over. bees to transport pollen 0 Mediterranean basin This is a particularly rich area for bees. Spain alone has more than 1,000 species. DISTIBUTION Six global hotspots, all of which have a Mediterranean-style climate, are home to the greatest variety of bee species. Bee hotspots Central Asia Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan and Tajikistan have 1,924 recorded species, but the total is thought to be much higher. Humans have valued the Bee-lite zones West coast of the honeybee for millennia Only a few bee species live United States Chile for its honey and its in the tropics because the California contains 183 species have pollination of crops. climate does not support the many climatic and been described in Greater Cape region ora on which bees forage. oral zones, which the climatically At least 645 dierent Southern Australia Despite a wealth of owers, are home to nearly Mediterranean species of bee are 1,647 bees have been bees are rare in the Arctic. 2,000 species from areas of Chile, and found here, including described here, but MUSEUM, LONDON HISTORY MAP SOURCE: M KUHLMANN/NATURAL Antarctica is the only region many dierent 176 species in the many of the most 300–400 bee species in which there are no bees. families. deserts. primitive species. remain unnamed. S48 | NATURE | VOL 521 | 21 MAY 2015 © 2015 Macmillan Publishers Limited. All rights reserved BEES OUTLOOK FOM THE BEGINNING … For their rst few days, all larvae The number of eggs laid per lifetime varies from eight feed on royal jelly (a substance (or fewer) for some solitary species to more than one made in glands on the heads of Queens million for queens of some social species. worker bees). Future queens pupate for 12 days; In two to three continue to be fed royal jelly; Honeybees are social drones and weeks, bees worker bees and drones consume insects with dened Eggs hatch workers for metamorphose. bee bread, which is a mixture of castes: workers (sterile after 3 days. around 7. honey, pollen and water. females), drones (fertile males) and queens (fertile females). Pollen is produced on the anther DAY 4 DAYS 8 DAYS 2–3 WEEKS and transfers to bees. DEATH HATCHING Bees rub pollen from In a colony, 1–2% of Young bees emerge every other owers onto the honeybees specialize in year during the spring. female part of the removing dead bees, Bright ower to facilitate which keeps the colony petal reproduction. clean and healthy within colours the enclosed nests. attract bees and Some plants have other oil-producing glands The age of pollinators. called elaiophores, the oldest and specialized bees reported have evolved to 8 YEAS honeybees. collect oil instead BEE LIFE of pollen. FOAGING STOY Flowers are the main source of food for bees. DECLINE The domesticated honeybee is the Reliable data are scarce — but archetypal bee. Here, we outline the they point to a bleak future for honeybee’s life history and highlight some other species of wild bee. Three species many bees worldwide. of the stingless Trigona, which The global The decrease2 live in South increase in in domesticated America, obtain agriculture honeybee protein from that depends colonies in rotting meat. on animal central Europe Most species of bee are pollination in the between 1985 vegetarian. Bees rely on past 50 years1. and 2005. 300% 25% pollen for protein, and on nectar for sugar. The decrease in The proportion NESTING Some bees, such as the domesticated of wild bee species Hives are not the only Macropis, collect oils from honeybee that became extinct homes for bees. the plants to line the cells in colonies over a 120-year their nests and make food between 1947 period to 2010 for the larvae. Adult bees and 2005 in the in Chicago, rarely ingest the oils. 60% United States2. 50% Illinois3. US$70 billion The estimated global economic value of bee pollination to agriculture per year4. Honeybees are cavity nesters. Some species build hives that Mining bees lay eggs in are suspended, for example on underground tunnels that Honeybee workers live on average tree branches or gutters. Other they dig themselves. At the for three to six weeks between wild honeybee species build end of each tunnel is a cell spring and summer. Queen bees nests in hollow spaces such in which the eggs are laid. can live for up to ve years, as holes in fallen logs. Each cell hosts one egg, but hibernating through the winters. some species have nests containing up to 60 cells. Cuckoo bees behave in the same way as cuckoo birds and put their eggs into the nests of other bees. Mining-bee cell References: 1. Aizen, M. A. & Harder, L. D. Curr. Biol. 19, 915–918 (2009); 2. Potts, S. G. et al. Trends Ecol. Evol. 25, 345–353 (2010); 3. Burkle, L. A., Marlin, J. C. & Knight, T. M. Science 339, 1611–1615 (2013); 4. Kuhlmann, M. S. Afr. J. Bot. 75, 726–738 (2009). 21 MAY 2015 | VOL 521 | NATURE | S49 © 2015 Macmillan Publishers Limited. All rights reserved.