Generally, Apis mellifera are red/brown with black bands and orange yellow rings on abdomen. They have hair on thorax and less hair on abdomen. They also have a pollen basket on their hind legs. Honeybee legs are mostly dark brown/black.
There are two castes of females, sterile workers are smaller (adults 10-15 mm long), fertile queens are larger (18-20 mm). Males, called drones, are 15-17 mm long at maturity. Though smaller, workers have longer wings than drones. Both castes of females have a stinger that is formed from modified ovipositor structures. In workers, the sting is barbed, and tears away from the body when used. In both castes, the stinger is supplied with venom from glands in the abdomen. Males have much larger eyes than females, probably to help locate flying queens during mating flights.
There are currently 26 recognized subspecies of Apis mellifera, with differences based on differences in morphology and molecular characteristics. The differences among the subspecies is usually discussed in terms of their agricultural output in particular environmental conditions. Some subspecies have the ability to tolerate warmer or colder climates. Subspecies may also vary in their defensive behavior, tongue length, wingspan, and coloration. Abdominal banding patterns also differ - some darker and some with more of a mix between darker and lighter banding patterns.
Honeybees are partially endothermic -- they can warm their bodies and the temperature in their hive by working their flight muscles. (Clarke, et al., 2002; Milne and Milne, 2000; Pinto, et al., 2004; Seeley, et al., 1982)
Apis mellifera is native to Europe, western Asia, and Africa. Human introduction of Apis mellifera to other continents started in the 17th century, and now they are found all around the world, including east Asia, Australia and North and South America. (Sammataro and Avitabile, 1998; Winston, et al., 1981)
European honeybees prefer habitats that have an abundant supply of suitable flowering plants, such as meadows, open wooded areas, and gardens. They can survive in grasslands, deserts, and wetlands if there is sufficient water, food, and shelter. They need cavities (e.g. in hollow trees) to nest in. (Milne and Milne, 2000; Winston, et al., 1981)
Honeybees build a hive out of wax secretions from their bodies, and queens lay their eggs in cells in the wax. The speed of subsequent development of the young is strongly affected by temperature, and is fastest at 33-36°C.
Honeybees are holometabolous insects, and have four stages in the life cycle: egg, larva, pupa, and adult.
A. mellifera eggs hatch in 28-144 hours, depending on their temperature. The larva that emerges is a small white grub. It stays in its wax cell, growing, and is fed and groomed by adult workers. The food that a female larva receives determines whether it will be a queen or worker. At 34°C, larvae feed and grow for 4-5 days, queens for 6 days, and males for 6-7 days. At the end of that period their cell is sealed by adult workers, and the larva molts, spins a silk cocoon, and transforms into the pupa stage. Pupae undergo a massive metamorphosis that takes about 7-8 days for queens, 12 days for workers, and 14-15 days for males. Once their final metamorphosis is complete, they chew their way out of the cell and begin their adult life. They will not grow or molt after emerging. Adult workers will live for 2-4 weeks in the summer, or as long as 11 months if they live through the winter. Males only survive for 4-8 weeks, and do not live through the winter. Queens live 2-5 years.
. The next stage is the larval stage where the larva is fed the royal jelly, pollen/nectar, and honey combination. Next the larva goes into the pupae stage where it caps itself into its cell to metamorphose into the mature stage.
The great majority of female A. mellifera in a hive are sterile workers. Only queens mate and lay eggs. Normally there is only a single reproductive queen in a hive.
During periods of suitably mild weather in spring and summer, males leave the hive and gather at "drone assembly areas" near the hive. Virgin queens will fly through these areas, attracting the males with pheromones. The males pursue, and attempt to mate with the queen in flight. Sometimes a "comet" forms, as a cluster of males forms around the female, with a string of other males trying to catch up. Each male who succeeds in mating drops away, and dies within a few hours or days. Males who do not mate will continue to loiter in the assembly areas until they mate or die trying. Queens will mate with up to 10 males in a single flight.
Queens may mate with males from their own hive, or from other hives in the area. The queen's mating behavior is centered around finding the best place to mate beforehand, by taking directional flights for a period of time, lasting no more than a couple of days. Afterward, she leaves the hive and flies to mate with drones in an assembly area. This normally starts to occur after their first week of birth. The queen does this up to four times. After this congregate of mating has occurred, she never mates again in her lifetime. (Adjare, 1990; Sammataro and Avitabile, 1998; Tarpy and Page Jr., 2000)
Apis mellifera queens are the primary reproducers of the nest and all of the activities of the colony are centered around their reproductive behaviors and their survival. The queen is the only fertile female in the colony. She lays eggs nearly continuously throughout the year, sometimes pausing in late fall in cold climates. A particularly fertile queen may lay as many as 1,000 eggs/day, and 200,000 eggs in her lifetime. It takes a queen about 16 days to reach adulthood, and another week or more to begin laying eggs. Males take about 24 days to emerge as adults, and begin leaving the nest for assembly areas a few days after that.
Queen honeybees can control whether or not an egg they lay is fertilized. Unfertilized eggs develop as males and are haploid (have only one set of chromosomes). Fertilized eggs are diploid (two sets of chromosomes) and develop as workers or new queens, depending on how they are fed as larvae. Queens may increase the ratio of male to female eggs they lay if they are diseased or injured, or in response to problems in the colony.
Healthy, well-fed honeybee colonies reproduce by "swarming." The workers in the colony begin by producing numerous queen larvae. Shortly before the new queens emerge, the resident, egg-laying queen leaves the hive, taking up to half the workers with her. This "swarm" forms a temporary group in a tree nearby, while workers scout for a suitable location for a new hive. Once they find one, the swarm moves into the space, and begins building comb and starting the process of food collection and reproduction again.
Meanwhile at the old hive, the new queens emerge from their cells. If the population of workers is large enough, and there are few queens emerging, then the first one or two may leave with "afterswarms" of workers. After the swarming is completed, any remaining new queens try to sting and kill each other, continuing to fight until all but one is dead. After her competition is removed, the surviving queen begins to lay eggs.
Normally the pheromones secreted by a healthy queen prevent workers from reproducing, but if a colony remains queenless for long, some workers will begin laying eggs. These eggs are unfertilized, and so develop as males. (Adjare, 1990; Milne and Milne, 2000; Sammataro and Avitabile, 1998; Tarpy and Page Jr., 2000)
As in most eusocial insects, the offspring of fertile females (queens) are cared for other members of the colony. In honeybees, the caretakers are sterile females, daughters of the queen, called workers.
Workers build and maintain the comb where young bees are raised, gather food (nectar and pollen) feed and tend larvae, and defend the hive and its young from predators and parasites.
Young queens inherit their hive from their mothers. Often several new queens emerge after the old queen leaves with a swarm to found a new colony. The new queens fight for control of the hive, and only one survives the conflict. (Adjare, 1990; Sammataro and Avitabile, 1998)
Apis mellifera queens usually live 2 to 3 years, but some have been known to last for 5 years. Workers typically only live for a few weeks, sometimes a few months if their hive becomes dormant in winter. Males live for 4-8 weeks at the most. (Tarpy and Page Jr., 2000)
European honeybees are eusocial insects. They live in colonies that contain one reproductive female (the queen) and her offspring. Sterile female offspring of the queen (the workers) perform all the work of the colony and are by far the most numerous caste in the hive. Males and queens spend all their effort on reproduction, see the Reproduction sections for information on mating behavior and egg production.
A. mellifera workers show what is called "age polyethism." Their behaviors change as they get older. Newly emerged workers clean cells, preparing them for a new egg or for food storage. After a few days they shift to other hive maintenance work, removing waste and debris, fanning to maintain air circulation and temperature, processing nectar brought by foragers, and feeding the queen and larvae from glands in their head and body. In their second week of adult life workers' wax glands become active and they help build and repair the comb, while continuing to tend the queen and feed workers. Apis mellifera workers build a "comb", a sheet of hexagonal cells made of waxes they secrete. Each cell can house one larval bee, and cells are also used as protected storage space for honey (processed nectar) and pollen.
Between 12 and 25 days, workers take a turn guarding the hive, inspecting any bees that try to enter the hive - driving off strangers and attacking any other creatures that try to enter. After about three weeks, the workers food and wax glands atrophy, and they shift to foraging duty.
Foraging only occurs during daylight, but bees are active in the hive continuously.
In temperate climates, colonies store honey and pollen to feed on during the winter. During cold temperatures the workers and queen form a tight ball or cluster, working their flight muscles to generate heat and keep themselves warm. In warmer tropical regions, honeybees maintain smaller stores of food.
If a colony's nest conditions become too poor, the entire colony may move to a new site. This is particularly common in tropical honeybees, that move in response to seasonal drought. Beekeepers call this "absconding", and work to prevent it in domesticated colonies.
Swarming is a behavior in a nest where a new queen is born that takes the place of the older one in that hive. The departing queen normally takes some of the workers with her. Swarming bees send out worker scouts to look for a suitable home to take the place of the one they left. The swarm of bees is just temporary. They normally swarm over a twig or branch of a tree or anywhere that can be used temporarily as an intermediate nest. (Adjare, 1990; Sammataro and Avitabile, 1998)
Honeybees forage as close to the hive as possible, usually within a 3 kilometer radius around the hive (i.e. an area of about about 2800 hectares). If necessary, they can fly as far as 8-13 km to reach food or water. (Percival, 1947; Sammataro and Avitabile, 1998)
Apis mellifera communication is based on chemical signals, and most of their communication and perception behaviors are centered around scent and taste. The members of the hive colony are bound chemically to each other. Each hive has a unique chemical signature that hivemates use to recognize each other and detect bees from other colonies.
Within the hive, bees are in constant chemical communication with each other. Workers feed and groom each other, as well as larvae, drones, and the queen. In the process they pass on pheromones, chemical signals that indicate information about the health of the queen and the state of the colony.
Chemicals not only help with detecting the right signature of hives but also with foraging. Honeybees use scent to locate flowers from a distance. When a successful forager returns to the hive, it passes the scent of the flowers to its nest mates, to help them find the same patch of flowers.
Bees also use chemicals to signal outside the hive. When a worker stings something, her stinger releases an alarm pheromone that causes other bees to become agitated, and helps them locate the enemy.
Thought it's always dark in the hive, vision is important to honeybees outside. They can see other animals, and recognize flowers. The eyes of Apis species can detect ultraviolet light wavelengths that are beyond the visible spectrum. This allows them to locate the sun on cloudy days, and see markings on flowers that are only visible in ultraviolet light. One portion of honeybee's eyes is sensitive to polarized light, and they use this to navigate.
Workers and queens can hear vibrations. New queens call to each other and workers when they first emerge. Workers hear the vibrations of the waggle dances made by returning foragers.
Apis species have a particularly notable form of communication called "dancing." Foragers that have located an abundant supply of food do a dance to communicate the location of the patch to other foragers. A "round dance" indicates food within about 300 meters of the hive, and only communicates the presence of the flowers, not the direction, though workers will also get the scent from the food the forager has brought back. The more complicated "waggle dance" indicates the direction and distance of food further away, using the location of the sun and the bee's memory of the distance it flew to return to the hive. Symbolic communication is quite unusual among invertebrates, and these honeybee "dances" have been intensively studied. (Breed, et al., 1985; Milne and Milne, 2000; Reinhard, et al., 2004; Roat and Landim, 2008; Sammataro and Avitabile, 1998; Sandoz, et al., 2002; Sherman and Visscher, 2002)
Apis mellifera feed on pollen and nectar collected from blooming flowers. They also eat honey (stored, concentrated nectar) and secretions produced by other members of their colony.
Workers forage for food (nectar and pollen) for the entire colony. They use their tongues to suck up nectar, and store it in the anterior section of the digestive tract, called the crop. They collect pollen by grooming it off the bodies and onto special structures on their hind legs called pollen baskets.
Returning foragers transfer the nectar they have collected to younger worker bees that in turn feed other members of the hive, or process it into honey for long-term storage. They add enzymes to the honey, and store it in open cells where the water can evaporate, concentrating the sugars.
Young workers eat pollen and nectar, and secrete food materials, called “royal jelly” and “worker jelly”, from glands in their heads. This material is fed to young larvae, and the amount and type they get determines if they will be queens or workers.
Honeybees forage during daylight hours, but are equally active on cloudy or sunny days. They will not fly in heavy rain or high winds, or if the temperature is too extreme (workers can't fly when they get below 10°C). During the warm, calm weather the honeybees collect the most pollen even if it is cloudy. If the light intensity changes rapidly, they immediately stop working and return to the hive. If it lightly rains, pollen collection stops, because moisture inhibits the bee’s ability to collect it. However, nectar collection is not inhibited by light rain. Wind also affects the rate of pollen collection.
Honeybee workers are opportunistic. They will steal from other hives if they can. Hive-robbing can be dangerous, but a weakened or damaged hive may be raided by workers from other hives, especially when nectar flows in flowers are not abundant. Honeybees will also collect “honeydew,” the sweet fluid excreted by sap-feeding insects like aphids. (Adjare, 1990; Gonzalez, et al., 1995; Percival, 1947; Sammataro and Avitabile, 1998)
Honeybees have many adaptations for defense: Adults have orange and black striping that acts as warning coloration. Predators can learn to associate that pattern with a painful sting, and avoid them. Honeybees prefer to build their hives in protected cavities (small caves or tree hollows). They seal small openings with a mix of wax and resins called propolis, leaving only one small opening. Worker bees guard the entrance of the hive. They are able to recognize members of their colony by scent, and will attack any non-members that try to enter the hive. Workers and queens have a venomous sting at the end of the abdomen. Unlike queens, and unusual among stinging insects, the stings of Apis workers are heavily barbed and the sting and venom glands tear out of the abdomen, remaining embedded in the target. This causes the death of the worker, but may also cause a more painful sting, and discourage the predator from attacking other bees or the hive. A stinging worker releases an alarm pheromone which causes other workers to become agitated and more likely to sting, and signals the location of the first sting.
Honeybees are subject to many types of predators, some attacking the bees themselves, others consuming the wax and stored food in the hive. Some predators are specialists on bees, including honeybees.
Important invertebrate enemies of adult bees include crab spiders and orb-weaver spiders, wasps in the genus Philanthus (called “beewolves”), and many species of social wasps in the family Vespidae. Vespid wasp colonies are known to attack honeybee colonies en masse, and can wipe out a hive in one attack. Many vertebrate insectivores also eat adult honeybees. Toads (Bufo) that can reach the entrance of hive will sit and eat many workers, as will opossums (Didelphis). Birds are an important threat – the Meropidae (bee-eaters) in particular in Africa and southern Europe, but also flycatchers around the world (Tyrranidae and Muscicapidae). Apis mellifera in Africa are also subject to attack by honeyguides. These birds eat hive comb, consuming bees, wax, and stored honey. At least one species, the greater honeyguide (Indicator indicator) will guide mammal hive predators to hives, and then feed on the hive after the mammal has opened it up.
The main vertebrate predators of hives are mammals. Bears frequently attack the nests of social bees and wasps, as do many mustelids such as the tayra in the Neotropics and especially the honey badger of Africa and southern and western Asia. In the Western Hemisphere skunks, armadillos and anteaters also raid hives, as do pangolins (Manis) in Africa. Large primates, including baboons, chimpanzees (<<g.Pan>>) and gorillas are reported to attack hives too. Smaller mammals such as mice (Mus) and rats (Rattus) will burrow into hives as well.
Some insects are predators in hives as well, including wax moth larvae (Galleria mellonella, Achroia grisella), and hive beetles (Hylostoma, Aethina), and some species of ants. In their native regions these tend not to be important enemies, but where honeybees have not co-evolved with these insects and have no defense, they can do great harm to hives.
Honeybees are very important pollinators, and are the primary pollinator for many plants. Without honeybees, these plants have greatly reduced fertility. In North America and Australia, where there are no native bee species with large colonies, honeybees can have especially strong effects on native flowers, and on other pollinators such as solitary bee species. Honeybees ability to recruit fellow workers by “dancing” allows them to be more efficient than other pollinators at exploiting patches of flowers. This can create strong impacts on their competitors, especially solitary bees.
Like all social insects, honeybees are hosts to a variety of parasites, commensal organisms, and pathogenic microbes. Some of these can be serious problems for apiculture, and have been studied intensively. At least 18 types of viruses have been found to cause disease in bees, including Sacbrood disease. Several of them (but not sacbrood virus) are associated with parasitic mites. Bacteria infect bees, notably Bacillus larvae, agent of American Foulbrood disease, and Melissococcus pluton, agent of European Foulbrood. Fungi grow in bee hives, and Ascosphaera apis can cause Chalkbrood disease. One of the most common diseases in domesticated hives is Nosema disease, caused by a protozoan, Nosema apis. An amoeba, Malphigamoeba mellificae, also causes disease in honeybees.
In recent decades, two mite species have spread through domesticated and feral honeybee populations around the world. Acarapis woodi is a small mite species that lives in the tracheae of adult bees and feeds on bee hemolymph. It was first discovered in Europe, but its origin is unknown. Infestations of these mites weaken bees, and in cold climates, whole colonies may fail when the bees are confined in the hive during the winter. A much worse threat is Varroa destructor. This might evolved on an Asian honeybee, Apis cerana, but switched on to Apis mellifera colonies that were set up in east Asia. It has since spread all around the world, except Australia. Juvenile mites feed on bee larvae and pupae, and adult female mites feed and disperse on adult workers. This mite is known to spread several viruses as well. Infestations of V. destructor often wipe out colonies. Nearly all the feral, untended honeybee colonies in North American are believed to have been wiped out by mite infestations, along with a large proportion of domesticated colonies. Other mite species are known from honeybee colonies, but they are not considered harmful.
Another commensal or parasitic species is Braula coeca, the bee louse. Despite the common name, this is actually a wingless fly, that apparently feeds by intercepting food being transferred from one bee to another.
Beetles in the genera Hylostoma and Aethina are found in African honeybee nests, where they seem to do little harm. However, the "small hive beetle", Aethina tumida, has become a significant problem in European and North American hives. The larvae eat all the contents of comb: honey, pollen, and bee eggs and larvae. (Adjare, 1990; Roubik, 1989; Sammataro and Avitabile, 1998)
Honeybee workers will sting humans and domesticated animals in defense of themselves or their hive. A single sting is painful but not dangerous unless the target is allergic to the venom, in which case it can be life threatening. Otherwise, it takes about 20 stings per kilogram of body weight to be life threatening.
Each subspecies of Apis mellifera has different behavioral patterns in regards to intruders near or around the hive. The African subspecies are particularly aggressive. One of them, Apis mellifera scutellata, was accidentally released in South America, and has spread north to the southern United States. This is the "killer bee." It is notable for having a much higher aggressive response to disturbance -- more workers attack than in other subspecies, and they pursue targets much longer than European bees do. The spread of these bees made beekeeping much more expensive and complicated, and the aggressive bees caused many deaths. (Adjare, 1990; Sammataro and Avitabile, 1998)
Honeybees pollinate billions of US dollars worth of commercial agricultural crops around the world every year. They are important pollinators for economically important wild plant populations as well.
Honeybee hives provide honey and wax, and pollen, propolis, and royal jelly that are sold for medicines and cosmetics.
Honeybees are important study organisms for research in the connections between nervous system structure and behavior.
While the species as a whole is still very numerous, there is concern in Europe that widespread commercialization of beekeeping is endangering locally-adapted populations and subspecies. This, combined with higher mortality of colonies due to Varroa mite and tracheal mite infestations, and the recent phenomenon of Colony Collapse Disorder in North America, has cause significant concern for the health of the population. Colony Collapse Disorder (CCD) is a condition of commercial beehives, where there are sudden massive waves of mortality among the workers. Beekeepers discover their hives simply empty of workers, with so few surviving that they cannot tend the queen and brood. This condition has occurred mainly in North America, and mainly in large commercial apiaries. No single cause has been identified yet. (Adjare, 1990; Sammataro and Avitabile, 1998)
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