Adult bees are short stout insects. They are fuzzier than their relatives the wasps and the ants. They have chewing mouthparts, four wings, and straight antennae. Most of them have yellow and black stripes, but some are bright green, and some are all black. Most bees can give a painful sting. Bee larvae and pupae are never found outside their nest. Bee larvae look like grubs, with soft white bodies, no legs and brown heads. Honey bee queens are larger than other members of their colony, with workers being the smallest and male drones ranging in the middle.
There are thousands of species of Bees all around the world. Bees can and do live in almost kind of climate. The only places bees do not live are in places with extreme cold all year round. In Michigan there are probably nearly 200 species.
Apidae species live anywhere there are flowers to feed from. Some bumble bees can tolerate very cold temperatures and live in the far north and high in the mountains.
Bees are holometabulous insects. This means that they undergo complete metamorphosis, passing through egg, larval, and pupal stages before emerging as an adult.
Eggs are elongate, white, gently curved, and have a soft membranous shell. In social species, eggs are not laid with any food as workers begin to feed larvae as soon as they hatch. In solitary species, eggs are laid upon or near a food source enclosed in a cell with the larvae.
Larvae are soft, whitish and grublike. They grow quickly, molting about four times as they mature. The honeybee has 5 larval instars (molts). Cleptoparasitic taxa hatch from the egg with a large sclerotized head and long curved mandibles, which they use to kill the host larvae or egg. They then begin to eat the hosts’ food source, and after the first molt take on the normal grublike appearance of other bee larvae. Apidae larvae are unable to defecate as there is no connection between the midgut and hindgut. In solitary bees, after the larval food source is gone the bee will defecate, and then almost immediately pupate. Many bee larvae spin silken cocoons for themselves.
Fertalized eggs develop into females while unfertalized eggs develop into males. After mating, the female stores the sperm in her spermatheca. Mating only one time will give her enough sperm for the rest of her life. As an egg pass down her oviduct, she controls whether it gets fertilized, by allowing whether or not sperm can exit the spermatheca as the egg passes.
Some males fly over or around flowers, literally pouncing on females in order to mate with them. Copulation lasts from a few seconds to a few minutes at most. A male will grasp the female with his legs and sometimes his mandibles in order to hold on while they copulate.
Many female bees only mate once, and males compete to get at them first. Some males even dig down into the soil to encounter a virgin female as she emerges from her larval cell. Most males bees are able to mate multiple times, although Meliponini and Apini male genitalia is torn away during copulation, after which the male soon dies. Some females that regularly mate more than once are found in the genus Panurgus. (Michener, 2000; Ramel, 2005; Michener, 2000; Ramel, 2005)
Most bee species are solitary nesters. The female makes a tiny bee-sized chamber for each of her offspring, lays one egg, and supplies the chamber with a ball of pollen and nectar for the baby bee to eat. Then she seals up the chamber and builds another one. Some bees, like bumble bees and honey bees, are more social and build nests or hives. In social bee species, a single queen lays the eggs, while most of her daughters don't reproduce but stay with their mother and help take care of more and more sisters (on average, 60 thousand). Some of the sisters are raised to be new queens, and they and their brothers fly away in the summer to mate and start new nests. (von Frisch, 1950)
Most bees are solitary nesters. Solitary bees construct their own nests, stocking each brood cell with a ball of pollen and nectar before laying one egg, sealing the cell, and building another. Solitary bees generally dye or leave before their offspring mature. When solitary bees do not leave before their offspring mature, but continue to feed and care for them, they are called subsocial bees.
A colony is made up of 2 or more adult females, regardless of their social relationship. We usually think of a colony in terms of having many workers (all sisters), which do all of the foraging, brood care, guarding, and building, and one queen who is responsible for all egg laying. This is in fact the life of many honeybees (Apis, Trigona, Melipona), and they are considered to be highly eusocial. The queen is completely dependant on her workers, and new colonies are started by social swarms, which fly as a group to a new area never leaving a queen by herself.
Other bees live in much smaller colonies such as bumblebees (Bombini), sweat bees (Halictidae) and carpenter bees (Xylocopinae). Their colonies begin with a single reproductive female who carries out all tasks of nest maintenance including foraging, brood care, and egg laying. After the emergence of daughters, colonial life and a division of labor between the foundress (queen) and her daughters may arise. These colonies are called primitively eusocial colonies. Often, the queen is larger than her workers, but this is not a constant rule.
Bee nests are made up of brood cells, usually with one egg laid in each cell. Most Bombus species however, lay a cluster of eggs together in a wax cell. Cells are made of wax, or dug into wood, soil, plant stems, or mortar. The most complex bee nests are made by Meliponini species, where clusters (combs) of wax brood cells are surrounded by layers of wax or resin food storage chambers, which are further surrounded by layers of wax mixed with resin or mud to protect the colony inside.
Other types of colonies include 2 or more reproductive females who each provision their own egg cells. This is called communal nesting. Most species that make communal nests also have individuals who nest alone. Communal nests can be made up of many species. It is not uncommon to find both solitary bees and wasps nesting communally together. This is especially common in areas where suitable nesting habitat is difficult to find, so individuals nest together in the only suitable areas available. The largest recorded communal nest aggregation was 423,000 bees covering 1300m squared.
Solitary bees tend to line their brood cells with a waterproofing material to protect developing offspring. This material can be wax, pieces of leaves and petals, or varnish-like and made from saliva. (Gauld and Bolton, 1988; Michener, 2000; Ramel, 2005; von Frisch, 1950)
Solitary female bees don't tend their babies after they close up their chamber. Bee species that form nests don't seal up the larvae, instead they feed and take care of them as they grow. Male bees never take care of offspring and do very little work.
Solitary bees hatch in the summer or fall and spend the winter in their nest. They emerge in the spring or summer to reproduce and then die. Among social bees, queen bees can live for several years. The workers usually live just a few weeks or months, although some live through the winter. Male bees usually live a few months at most, and often die shortly after mating. (Michener, 2000)
Many bee species (called robber bees) are parasitic upon other bee species. These bees eat the stored food meant for the host larvae, starving or even directly killing the host.
Most bees forage during the day, whenever it is warm enough. Honeybees build large hives out of wax, high up in trees or cliffs. Bumblebees make smaller nests in holes underground, usually abandoned mammal burrows. Almost any kind of protected niche can be used by bees as a nesting site, such as beetle bored cavities in timber, holes in walls or hollow trees, snail shells, or under rocks. Some use abandoned bird nests, dead plant stems, or may tunnel into the mortar of houses and walls.
A few bees are nocturnal, and specialize on collecting pollen from certain night blooming flowers. Perdita species collect pollen only from evening primroses and their close relatives, and members of the cucumber family are frequented by Xenoglossa. In order to see better at night, nocturnal bees tend to have larger eyes and darker coloring. (Gauld and Bolton, 1988; Michener, 2000; Ramel, 2005)
Social bees communicate a lot, using chemicals, visual signals, the vibrations of their wings, and touch. They exchange information that helps them know what's going on in the hive and what they should do.
Adult bees drink nectar and eat pollen, while larvae eat pollen, nectar, honey, and pollen or floral oils.
Pollen is collected by the female parent in solitary species, or by the foundress and or workers in colonies. Females collect pollen on branched body hairs, which are later transferred to the scopa (carrying structure), generally located on the hind legs. An exception to this are the Hylaeus, which are hairless and lack scopa, instead transporting pollen in their crops.
Bees normally collect dry pollen which is naturally sticky, but some bees mix pollen with regurgitated nectar to maximize its sticky qualities. In taxa that have scopa to carry the pollen, nectar is carried in the crop, and is then refined to make honey. Some bees collect floral oils instead of nectar. When a female returns to her nest she regurgitates her crop full of nectar or oil into a honey pot or preconstructed cell for storage. (Gauld and Bolton, 1988)
Many bees have a venomous stinger that they can use to attack creatures that threaten them or their nest. They also generally nest in places that are hard to reach, or they protect their nest by digging it out of dead wood, soil, or other material.
Bees are essential to the survival of many ecosystems, as without them many plants could not reproduce. Bees pollinate more plants than any other insect. They are so important, that many species of solitary bees in the family Megachile are farmed and cared for because of their importance in pollinating commercial crops.
Some plants have developed clever ways to trick bees into pollinating them. Certain orchids (Ophrys) emit pheromones similar to those of female Andrea, Anthophora, Colletes, Eucera, Tetralonia, and other bees. Males smell the pheromones and are attracted to the flowers thinking that they are female bees. As the male tries to mate with the flower, he pollinates it at the same time. (Ramel, 2005; Gauld and Bolton, 1988; Ramel, 2005)
Bees sting to protect themselves. They usually aren't dangerous, but large hives might sting a person enough times to endanger them, and some people are so allergic to bee stings that they can die from just one or a few stings.
Bees are very important to the production of fruits and vegetables, and other crops such as flax, cotton, alfalfa and clover. Without bees, most crops could not be grown. The pollination industry is worth millions every year.
Varroa mites are reducing bee populations throughout Europe and the Americas. Many bees are specialists, and the destruction of habitat coupled with the introduction of foreign honeybees is negatively effecting the polination of many plant species. Most bee species however, are not in danger.
Gordons Solitary Bee Page http://www.earthlife.net/insects/solbees.html has great links to beautiful color plates of bees from the turn of the century.
George Hammond (author), Animal Diversity Web.
Sara Diamond (author), Animal Diversity Web.
Gauld, I., B. Bolton. 1988. The Hymenoptera. New York, New York: Oxford University Press.
Ito, Y. 1993. Behavior and Social Evolution of Wasps. New York, New York: Oxford University Press.
Michener, C. 2000. The Bees of the World. Baltimore, Maryland, USA: The Johns Hopkins University Press.
Ramel, G. 2005. "Gordons Solitary Bee Page" (On-line). Accessed July 05, 2005 at http://www.earthlife.net/insects/solbees.html.
von Frisch, C. 1950. Bees: Their Vision, Chemical Senses, and Language. Ithica, New York: Cornell University Press.