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| The cat'" ("Felis catus"), also known as the domestic cat'" or "'house cat'" to distinguish it from other felines and felids, is a small predatory carnivorous species of crepuscular mammal that is valued by humans for its companionship and its ability to hunt vermin, snakes, scorpions, and other unwanted household pests. It has been associated with humans for at least 9,500 years. A skilled predator, the cat is known to hunt over 1,000 species for food. It can be trained to obey simple commands. Individual cats have also been known to learn on their own to manipulate simple mechanisms, such as doorknobs. Cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Cats may be the most popular pet in the world, with over 600 million in homes all over the world. They are also bred and shown as registered pedigree pets. This hobby is known as the "cat fancy." Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal. However a 2007 study found that the lines of descent of all house cats probably run through as few as five self-domesticating African Wildcats "(Felis silvestris lybica)" circa 8000 BC, in the Near East. Size. Cats typically weigh between 2.5 and 7 kg (5.5–16 pounds); however, some, such as the Maine Coon, can exceed. Some have been known to reach up to due to overfeeding. Conversely, very small cats (less than) have been reported. The largest cat ever was officially reported to have weighed in at about (46 lb 15.25 oz). The smallest cat ever officially recorded weighed around 3 lbs (1.36 kg). Cats average about in height and in head body length (males being larger than females), with tails averaging in length. Skeleton. Cats have 7 cervical vertebrae like almost all mammals, 13 thoracic vertebrae (humans have 12), 7 lumbar vertebrae (humans have 5), 3 sacral vertebrae like most mammals (humans have 5 because of their bipedal posture), and, except for Manx cats, 22 or 23 caudal vertebrae (humans have 3 to 5, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared with humans. The caudal vertebrae form the tail, used by the cat as a counterbalance to the body during quick movements. Cats also have free-floating clavicle bones, which allows them to pass their body through any space into which they can fit their heads. Mouth. Cats have highly specialized teeth for the killing of prey and the tearing of meat. The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently functions to shear meat like a pair of scissors. While this is present in canids, it is highly developed in felines. The cat's tongue has sharp spines, or papillae, useful for retaining and ripping flesh from a carcass. These papillae are small backward-facing hooks that contain keratin which also assist in their grooming. As facilitated by their oral structure, cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Ears. Thirty-two individual muscles in each ear allow for a manner of directional hearing: a cat can move each ear independently of the other. Because of this mobility, a cat can move its body in one direction and point its ears in another direction. Most cats have straight ears pointing upward. Unlike dogs, flap-eared breeds are extremely rare (Scottish Folds are one such exceptional mutation.) When angry or frightened, a cat will lay back its ears, to accompany the growling or hissing sounds it makes. Cats also turn their ears back when they are playing, or to listen to a sound coming from behind them. The angle of cats' ears is an important clue to their mood. Legs. Cats, like dogs, are digitigrades. They walk directly on their toes, with the bones of their feet making up the lower part of the visible leg. Cats are capable of walking very precisely, because like all felines they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain. Claws. Like nearly all members of family Felidae, cats have protractable claws. In their normal, relaxed position the claws are sheathed with the skin and fur around the toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hind feet. Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces (bedspreads, thick rugs, etc.). It is also possible to make a cooperative cat extend its claws by carefully pressing both the top and bottom of the paw. The curved claws may become entangled in carpet or thick fabric, which may cause injury if the cat is unable to free itself. Most cats have five claws on their front paws, and four or five on their rear paws. Because of an ancient mutation, however, domestic and feral cats are prone to polydactylyism, (particularly in the east coast of Canada and north east coast of the United States) and may have six or seven toes. The fifth front claw (the dewclaw) is proximal to the other claws. More proximally, there is a protrusion which appears to be a sixth "finger". This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of big cats and dogs. It has no function in normal walking, but is thought to be an anti-skidding device used while jumping. Skin. Cats possess rather loose skin; this allows them to turn and confront a predator or another cat in a fight, even when it has a grip on them. This is also an advantage for veterinary purposes, as it simplifies injections. In fact, the lives of cats with kidney failure can sometimes be extended for years by the regular injection of large volumes of fluid subcutaneously, which serves as an alternative to dialysis. The particularly loose skin at the back of the neck is known as the "scruff", and is the area by which a mother cat grips her kittens to carry them. As a result, cats tend to become quiet and passive when gripped there. This behavior also extends into adulthood, when a male will grab the female by the scruff to immobilize her while he mounts, and to prevent her from running away as the mating process takes place. This technique can be useful when attempting to treat or move an uncooperative cat. However, since an adult cat is heavier than a kitten, a pet cat should never be carried by the scruff, but should instead have its weight supported at the rump and hind legs, and at the chest and front paws. Often (much like a small child) a cat will lie with its head and front paws over a person's shoulder, and its back legs and rump supported under the person's arm. Senses. Cat senses are attuned for hunting. Cats have highly advanced hearing, eyesight, taste, and touch receptors, making the cat extremely sensitive among mammals. Cats' night vision is superior to humans although their vision in daylight is inferior. Cat eyes have a tapetum lucidum and cat eyes that are blue typically lack melanin and hence can show the red-eye effect (see odd-eyed cat). Humans and cats have a similar range of hearing on the low end of the scale, but cats can hear much higher-pitched sounds, up to 64 kHz, which is 1.6 octaves above the range of a human, and even one octave above the range of a dog. A domestic cat's sense of smell is about fourteen times as strong as a human's. Due to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness may have been lost by the cat family. To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face. Metabolism. Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term "cat nap" refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon – someone who nods off for a few minutes is said to be "taking a cat nap". Due to their crepuscular nature, cats are often known to enter a period of increased activity and playfulness during the evening and early morning, dubbed the "evening crazies", "night crazies", "elevenses", or "mad half-hour" by some. The temperament of a cat can vary depending on the breed and socialization. Cats with oriental body types tend to be thinner and more active, while cats that have a cobby body type tend to be heavier and less active. The normal body temperature of a cat is between 38 and 39 °C (101 and 102.2 °F). A cat is considered febrile (hyperthermic) if it has a temperature of 39.5 °C (103 °F) or greater, or hypothermic if less than 37.5 °C (100 °F). For comparison, humans have a normal temperature of approximately 36.8 °C (98.6 °F). A domestic cat's normal heart rate ranges from 140 to 220 beats per minute, and is largely dependent on how excited the cat is. For a cat at rest, the average heart rate usually is between 150 and 180 bpm, about twice that of a human (average 80 bpm). Genetics. A 2007 study published in the journal "Science" asserts that all house cats are descended from a group of self-domesticating desert wildcats "Felis silvestris lybica" circa 10,000 years ago, in the Near East. The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes, in which over 200 heritable genetic defects have been identified, many homologous to human inborn errors. Specific metabolic defects have been identified underlying many of these feline diseases. There are several genes responsible for the hair color identified. The combination of them gives different phenotypes. Features like hair length, lack of tail, or presence of a very short tail (bobtail cat) are also determined by single alleles and modified by polygenes. The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, focuses on the development of the cat as an animal model for human hereditary disease, infectious disease, genome evolution, comparative research initiatives within the family Felidae, and forensic potential. All felines, including the big cats, have a genetic anomaly that may prevent them from tasting sweetness, which is a likely factor for their indifference to or avoidance of fruits, berries, and other sugary foods. Feeding and diet. Cats feed on small prey such as insects, birds, and rodents. Feral cats, or house cats who are free-fed, consume about 8 to 16 small meals in a single day. Despite this, adult cats can adapt to being fed once a day. Cats are classified as obligate carnivores, because their physiology is geared toward efficient processing of meat, and lacks efficient processes for digesting plant matter. The cat cannot produce its own taurine (an essential organic acid), and, as it is contained in flesh, the cat must eat flesh to survive (see Taurine and cats). Similarly as with its teeth, a cat's digestive tract has become specialized over time to suit meat eating, having shortened in length only to those segments of intestine best able to break down proteins and fats from animal flesh. This trait severely limits the cat's ability to properly digest, metabolize, and absorb plant-derived nutrients, as well as certain fatty acids. For example, taurine is scarce in plants but abundant in meats. It is a key amino sulfonic acid for eye health in cats. Taurine deficiency can cause a condition called macular degeneration wherein the cat's retina slowly degenerates, eventually causing irreversible blindness. Despite the cat's meat-oriented physiology, it is still quite common for a cat to supplement its carnivorous diet with small amounts of grass, leaves, shrubs, houseplants, or other plant matter. One theory suggests this behavior helps cats regurgitate if their digestion is upset; another is that it introduces fiber or trace minerals into the diet. In this context, caution is recommended for cat owners because some houseplants are harmful to cats. For example, the leaves of the Easter Lily can cause permanent and life-threatening kidney damage to cats, and Philodendron are also poisonous to cats. The Cat Fanciers' Association has a full list of plants harmful to cats. There are several vegetarian or vegan commercially available cat foods supplemented with chemically synthesized taurine and other added nutrients that attempt to address nutritional shortfalls. Cats can be selective eaters (which may be due in some way to the aforementioned mutation which caused their species to lose sugar-tasting ability). However, cats generally cannot tolerate lack of food for more than 36 hours without risking liver damage. Cats have a fondness for catnip, which is sensed by their olfactory systems. Many enjoy consuming catnip, and most will often roll in it, paw at it, and occasionally chew on it. Cats also can also develop odd eating habits. Some cats like to eat or chew on other things like plastic, paper, string, wool, or even coal. This condition is called pica and can threaten the cat's health depending on the amount and toxicity of the non-food items eaten. The condition's name comes from the Latin word for magpie, a bird which is reputed to eat almost anything. Toxic sensitivity. The liver of a cat is less effective at detoxification than those of other animals, including humans and dogs; therefore exposure to many common substances considered safe for households may be dangerous to them. In general, the cat's environment should be examined for the presence of such toxins and the problem corrected or alleviated as much as possible; in addition, where sudden or prolonged serious illness without obvious cause is observed, the possibility of toxicity must be considered, and the veterinarian informed of any such substances to which the cat may have had access. For instance, the common painkiller paracetamol or acetaminophen, sold under brand names such as Tylenol and Panadol, is extremely toxic to cats; because they naturally lack enzymes needed to digest it, even minute portions of doses safe for humans can be fatal and any suspected ingestion warrants immediate veterinary attention. Even aspirin, which is sometimes used to treat arthritis in cats, is much more toxic to them than to humans and must be administered cautiously. Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidental or by well-meaning owners attempting to counter loss of fur, has sometimes proved fatal. In addition to such obvious dangers as insecticides and weed killers, other common household substances that should be used with caution in areas where cats may be exposed to them include mothballs and other naphthalene products, as well as phenol based products often used for cleaning and disinfecting near cats' feeding areas or litter boxes, such as Pine-Sol, Dettol (Lysol), hexachlorophene, "etc." which, although they are widely used without problem, have been sometimes seen to be fatal. Ethylene glycol, often used as an automotive antifreeze, is particularly appealing to cats, and as little as a teaspoonful can be fatal. Essential oils are toxic to cats and there have been reported cases of serious illnesses caused by tea tree oil, and tea tree oil-based flea treatments and shampoos. Many human foods are somewhat toxic to cats; theobromine in chocolate can cause theobromine poisoning, for instance, although few cats will eat chocolate. Toxicity in cats ingesting relatively large amounts of onions or garlic has also been reported. Even such seemingly safe items as cat food packaged in pull tab tin cans have been statistically linked to hyperthyroidism; although the connection is far from proven, suspicion has fallen on the use of bisphenol A-based plastics, another phenol based product as discussed above, to seal such cans. Many houseplants are at least somewhat toxic to many species, cats included and the consumption of such plants by cats is to be avoided. Sociability. For cats, life in close proximity with humans (and other animals kept by humans) amounts to a "symbiotic social adaptation" which has developed over thousands of years. It has been suggested that, ethologically, the human keeper of a cat functions as a sort of surrogate for the cat's mother, and that adult domestic cats live their lives in a kind of extended kittenhood, a form of behavioral neoteny. Cats may express affection towards their human companions, especially if they imprint on them at a very young age and are treated with consistent affection. Regardless of the average sociability of any given cat or of cats in general, there are still any number of cats who meet or exceed the negative feline stereotype insofar as being poorly socialized. Older cats have also been reported to sometimes develop aggressiveness towards kittens, which may include biting and scratching; this type of behavior is known as Feline Asocial Aggression. Cohabitation. One may see natural house cat behavior by observing feral domestic cats, which are social enough to form colonies. Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, and neutered cats having the smallest. Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually aggressively chase away stranger cats, at first by staring, hissing, and growling, and if that does not work, by short but noisy and violent attacks. Despite cohabitation in colonies, cats do not have a social survival strategy, or a pack mentality. This mainly means that an individual cat takes care of all basic needs on its own (e.g., finding food, and defending itself), and thus cats are always lone hunters; they do not hunt in groups as dogs or lions do. Cats frequently tonguebathe themselves (see hygiene). The chemistry of their saliva, expended during their frequent grooming, appears to be a natural deodorant. Thus, a cat's cleanliness would aid in decreasing the chance a prey animal could notice the cat's presence. By contrast, dog odor is an advantage in hunting, for a dog is a pack hunter; part of the pack stations itself upwind, and its odor drives prey towards the rest of the pack stationed downwind. This requires a cooperative effort, which in turn requires communication skills. No such communication skills are required of a lone hunter. Fighting. When engaged in feline-to-feline combat for self-defense, territory, reproduction, or dominance, fighting cats make themselves appear more impressive and threatening by raising their fur and arching their backs, thus increasing their apparent size. Cats also behave this | Bees'" are flying insects closely related to wasps and ants. Bees are a monophyletic lineage within the superfamily "'Apoidea'", presently classified by the unranked taxon name "'Anthophila'". There are nearly 20,000 known species of bee, in nine recognized families, though many are undescribed and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. Introduction. Bees are adapted for feeding on nectar and pollen, the former primarily as an energy source, and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae. Bees have a long proboscis (a complex "tongue") that enables them to obtain the nectar from flowers. They have antennae almost universally made up of 13 segments in males and 12 in females, as is typical for the superfamily. Bees all have two pairs of wings, the hind pair being the smaller of the two; in a very few species, one sex or caste has relatively short wings that make flight difficult or impossible, but none is wingless. The smallest bee is "Trigona minima", a stingless bee whose workers are about 2.1 mm (5 64") long. The largest bee in the world is "Megachile pluto", a leafcutter bee whose females can attain a length of 39 mm (1.5"). Members of the family Halictidae, or sweat bees, are the most common type of bee in the Northern Hemisphere, though they are small and often mistaken for wasps or flies. The best-known bee species is the European honey bee, which, as its name suggests, produces honey, as do a few other types of bee. Human management of this species is known as beekeeping or apiculture. Bees are the favorite meal of "Merops apiaster", the bee-eater bird. Other common predators are kingbirds, mockingbirds, bee wolves, and dragonflies. Pollination. Bees play an important role in pollinating flowering plants, and are the major type of pollinator in ecosystems that contain flowering plants. Bees either focus on gathering nectar or on gathering pollen depending on demand, especially in social species. Bees gathering nectar may accomplish pollination, but bees that are deliberately gathering pollen are more efficient pollinators. It is estimated that one third of the human food supply depends on insect pollination, most of which is accomplished by bees, especially the domesticated European honey bee. Contract pollination has overtaken the role of honey production for beekeepers in many countries. Monoculture and the massive decline of many bee species (both wild and domesticated) have increasingly caused honey bee keepers to become migratory so that bees can be concentrated in seasonally-varying high-demand areas of pollination. Most bees are fuzzy and carry an electrostatic charge, which aids in the adherence of pollen. Female bees periodically stop foraging and groom themselves to pack the pollen into the scopa, which is on the legs in most bees, and on the ventral abdomen on others, and modified into specialized pollen baskets on the legs of honey bees and their relatives. Many bees are opportunistic foragers, and will gather pollen from a variety of plants, while others are oligolectic, gathering pollen from only one or a few types of plant. A small number of plants produce nutritious floral oils rather than pollen, which are gathered and used by oligolectic bees. One small subgroup of stingless bees, called "vulture bees," is specialized to feed on carrion, and these are the only bees that do not use plant products as food. Pollen and nectar are usually combined together to form a "provision mass", which is often soupy, but can be firm. It is formed into various shapes (typically spheroid), and stored in a small chamber (a "cell"), with the egg deposited on the mass. The cell is typically sealed after the egg is laid, and the adult and larva never interact directly (a system called "mass provisioning"). Visiting flowers can be a dangerous occupation. Many assassin bugs and crab spiders hide in flowers to capture unwary bees. Other bees are lost to birds in flight. Insecticides used on blooming plants kill many bees, both by direct poisoning and by contamination of their food supply. A honey bee queen may lay 2000 eggs per day during spring buildup, but she also must lay 1000 to 1500 eggs per day during the foraging season, mostly to replace daily casualties, most of which are workers dying of old age. Among solitary and primitively social bees, however, lifetime reproduction is among the lowest of all insects, as it is common for females of such species to produce fewer than 25 offspring. The population value of bees depends partly on the individual efficiency of the bees, but also on the population itself. Thus, while bumblebees have been found to be about ten times more efficient pollinators on cucurbits, the total efficiency of a colony of honey bees is much greater, due to greater numbers. Likewise, during early spring orchard blossoms, bumblebee populations are limited to only a few queens, and thus are not significant pollinators of early fruit. Depopulation. Recently, managed populations of European honey bees have experienced substantial declines. This has prompted investigations into the phenomenon amidst great concern over the nature and extent of the losses. One aspect of the problem is believed to be "Colony Collapse Disorder" but many of the losses outside the US are attributed to other causes. Pesticides used to treat seeds, such as Clothianidin and Imidacloprid, may also negatively impact honey bee populations. Other species of bees such as mason bees are increasingly cultured and used to meet the agricultural pollination need. Most native pollinators are solitary bees, which often survive in refuge in wild areas away from agricultural spraying, but may still be poisoned in massive spray programs for mosquitoes, gypsy moths, or other insect pests. Evolution. Bees, like ants, are a specialized form of wasp. The ancestors of bees were wasps in the family Crabronidae, and therefore predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of prey insects that were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario has also occurred within the vespoid wasps, where the group known as "pollen wasps" also evolved from predatory ancestors. Up until recently the oldest non-compression bee fossil had been "Cretotrigona prisca" in New Jersey amber and of Cretaceous age, a meliponine. A recently reported bee fossil, of the genus "Melittosphex", is considered "an extinct lineage of pollen-collecting Apoidea sister to the modern bees", and dates from the early Cretaceous (~100 mya). Derived features of its morphology ("apomorphies") place it clearly within the bees, but it retains two unmodified ancestral traits ("plesiomorphies") of the legs (two mid-tibial spurs, and a slender hind basitarsus), indicative of its transitional status. The earliest animal-pollinated flowers were pollinated by insects such as beetles, so the syndrome of insect pollination was well established before bees first appeared. The novelty is that bees are "specialized" as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are generally more efficient at the task than beetles, flies, butterflies, pollen wasps, or any other pollinating insect. The appearance of such floral specialists is believed to have driven the adaptive radiation of the angiosperms, and, in turn, the bees themselves. Among living bee groups, the Dasypodaidae are now considered to be the most "primitive", and sister taxon to the remainder of the bees, contrary to earlier hypotheses that the "short-tongued" bee family Colletidae was the basal group of bees; the short, wasp-like mouthparts of colletids are the result of convergent evolution, rather than indicative of a plesiomorphic condition. Eusocial and semisocial bees. Bees may be solitary or may live in various types of communities. The most advanced of these are eusocial colonies found among the honey bees, bumblebees, and stingless bees. Sociality, of several different types, is believed to have evolved separately many times within the bees. In some species, groups of cohabiting females may be sisters, and if there is a division of labor within the group, then they are considered semisocial. If, in addition to a division of labor, the group consists of a mother and her daughters, then the group is called eusocial. The mother is considered the "queen" and the daughters are "workers". These castes may be purely behavioral alternatives, in which case the system is considered "primitively eusocial" (similar to many paper wasps), and if the castes are morphologically discrete, then the system is "highly eusocial". There are many more species of primitively eusocial bees than highly eusocial bees, but they have rarely been studied. The biology of most such species is almost completely unknown. The vast majority are in the family Halictidae, or "sweat bees". Colonies are typically small, with a dozen or fewer workers, on average. The only physical difference between queens and workers is average size, if they differ at all. Most species have a single season colony cycle, even in the tropics, and only mated females (future queens, or "gynes") hibernate (called diapause). A few species have long active seasons and attain colony sizes in the hundreds. The orchid bees include a number of primitively eusocial species with similar biology. Certain species of allodapine bees (relatives of carpenter bees) also have primitively eusocial colonies, with unusual levels of interaction between the adult bees and the developing brood. This is "progressive provisioning"; a larva's food is supplied gradually as it develops. This system is also seen in honey bees and some bumblebees. Highly eusocial bees live in colonies. Each colony has a single queen, many workers and, at certain stages in the colony cycle, drones. When humans provide the nest, it is called a hive. A honey bee hive can contain up to 40,000 bees at their annual peak, which occurs in the spring, but usually have fewer. Bumblebees. Bumblebees ("Bombus terrestris", "B. pratorum", et al.) are eusocial in a manner quite similar to the eusocial Vespidae such as hornets. The queen initiates a nest on her own (unlike queens of honey bees and stingless bees which start nests via swarms in the company of a large worker force). Bumblebee colonies typically have from 50 to 200 bees at peak population, which occurs in mid to late summer. Nest architecture is simple, limited by the size of the nest cavity (pre-existing), and colonies are rarely perennial. Bumblebee queens sometimes seek winter safety in honey bee hives, where they are sometimes found dead in the spring by beekeepers, presumably stung to death by the honey bees. It is unknown whether any survive winter in such an environment. Stingless bees. Stingless bees are very diverse in behavior, but all are highly eusocial. They practice mass provisioning, complex nest architecture, and perennial colonies. Honey bees. The true honey bees (genus "Apis") have arguably the most complex social behavior among the bees. The European (or Western) honey bee, "Apis mellifera", is the best known bee species and one of the best known of all insects. Africanized honey bee. Africanized bees, also called killer bees, are a hybrid strain of "Apis mellifera" derived from experiments to cross European and African honey bees by Warwick Estevam Kerr. Several queen bees escaped his laboratory in South America and have spread throughout the Americas. Africanized honey bees are more defensive than European honey bees. Solitary and communal bees. Most other bees, including familiar species of bee such as the Eastern carpenter bee ("Xylocopa virginica"), alfalfa leafcutter bee ("Megachile rotundata"), orchard mason bee ("Osmia lignaria") and the hornfaced bee ("Osmia cornifrons") are solitary in the sense that every female is fertile, and typically inhabits a nest she constructs herself. There are no "worker" bees for these species. Solitary bees typically produce neither honey nor beeswax. They are immune from acarine and "Varroa" mites (see diseases of the honey bee), but have their own unique parasites, pests and diseases. Solitary bees are important pollinators, and pollen is gathered for provisioning the nest with food for their brood. Often it is mixed with nectar to form a paste-like consistency. Some solitary bees have very advanced types of pollen carrying structures on their bodies. A very few species of solitary bees are being increasingly cultured for commercial pollination. Solitary bees are often oligoleges, in that they only gather pollen from one or a few species genera of plants (unlike honey bees and bumblebees which are generalists). No known bees are nectar specialists; many oligolectic bees will visit multiple plants for nectar, but there are no bees which visit only one plant for nectar while also gathering pollen from many different sources. Specialist pollinators also include bee species that gather floral oils instead of pollen, and male orchid bees, which gather aromatic compounds from orchids (one of the only cases where male bees are effective pollinators). In a very few cases only one species of bee can effectively pollinate a plant species, and some plants are endangered at least in part because their pollinator is dying off. There is, however, a pronounced tendency for oligolectic bees to be associated with common, widespread plants which are visited by multiple pollinators (e.g., there are some 40 oligoleges associated with creosotebush in the US desert southwest, and a similar pattern is seen in sunflowers, asters, mesquite, etc.) Solitary bees create nests in hollow reeds or twigs, holes in wood, or, most commonly, in tunnels in the ground. The female typically creates a compartment (a "cell") with an egg and some provisions for the resulting larva, then seals it off. A nest may consist of numerous cells. When the nest is in wood, usually the last (those closer to the entrance) contain eggs that will become males. The adult does not provide care for the brood once the egg is laid, and usually dies after making one or more nests. The males typically emerge first and are ready for mating when the females emerge. Providing nest boxes for solitary bees is increasingly popular for gardeners. Solitary bees are either stingless or very unlikely to sting (only in self defense, if ever). While solitary females each make individual nests, some species are gregarious, preferring to make nests near others of the same species, giving the appearance to the casual observer that they are social. Large groups of solitary bee nests are called "aggregations", to distinguish them from colonies. In some species, multiple females share a common nest, but each makes and provisions her own cells independently. This type of group is called "communal" and is not uncommon. The primary advantage appears to be that a nest entrance is easier to defend from predators and parasites when there are multiple females using that same entrance on a regular basis. Cleptoparasitic bees. Cleptoparasitic bees, commonly called "cuckoo bees" because their behavior is similar to cuckoo birds, occur in several bee families, though the name is technically best applied to the apid subfamily Nomadinae. Females of these bees lack pollen collecting structures (the scopa) and do not construct their own nests. They typically enter the nests of pollen collecting species, and lay their eggs in cells provisioned by the host bee. When the cuckoo bee larva hatches it consumes the host larva's pollen ball, and if the female cleptoparasite has not already done so, kills and eats the host larva. In a few cases where the hosts are social species, the cleptoparasite remains in the host nest and lays many eggs, sometimes even killing the host queen and replacing her. Many cleptoparasitic bees are closely related to, and resemble, their hosts in looks and size, (i.e., the "Bombus" subgenus "Psithyrus", which are parasitic bumblebees that infiltrate nests of species in other subgenera of "Bombus"). This common pattern gave rise to the ecological principle known as "Emery's Rule". Others parasitize bees in different families, like "Townsendiella", a nomadine apid, one species of which is a cleptoparasite of the dasypodaid genus "Hesperapis", while the other species in the same genus attack halictid bees. Nocturnal bees. Four bee families (Andrenidae, Colletidae, Halictidae, and Apidae) contain some species that are crepuscular (these may be either the vespertine or matinal type). These bees have greatly enlarged ocelli, which are extremely sensitive to light and dark, though incapable of forming images. Many are pollinators of flowers that themselves are crepuscular, such as evening primroses, and some live in desert habitats where daytime temperatures are extremely high. Bee flight. In his 1934 French book "Le vol des insectes", M. Magnan wrote that he and a Mr. Saint-Lague had applied the equations of air resistance to bumblebees and found that their flight could not be explained by fixed-wing calculations, but that "One shouldn't be surprised that the results of the calculations don't square with reality". This has led to a common misconception that bees "violate aerodynamic theory", but in fact it merely confirms that bees do not engage in fixed-wing flight, and that their flight is explained by other mechanics. In 1996 Charlie Ellington at Cambridge University showed that vortices created by many insects’ wings and non-linear effects were a vital source of lift; vortices and non-linear phenomena are notoriously difficult areas of hydrodynamics, which has made for slow progress in theoretical understanding of insect flight. In 2005 Michael Dickinson and his Caltech colleagues studied honey bee flight with the assistance of high-speed cinematography and a giant robotic mock-up of a bee wing. Their analysis revealed sufficient lift was generated by "the unconventional combination of short, choppy wing strokes, a rapid rotation of the wing as it flops over and reverses direction, and a very fast wing-beat frequency". Wing beat frequency normally increases as size decreases, but as the bee's wing beat covers such a small arc, it flaps approximately 230 times per second, faster than a fruitfly (200 times per second) which is 80 times smaller. In 2008 Barbara Shipman discovered a mathematical connection between the dance of bees and the Flag manifold. Bees and humans. Bees figure prominently in mythology (See Bee (mythology)) and have been used by political theorists as a model for human society. Journalist Bee Wilson states that the image of a community of honey bees "occurs from ancient to modern times, in Aristotle and Plato; in Virgil and Seneca; in Erasmus and Shakespeare; Tolstoy, as well as by social theorists Bernard Mandeville and Karl Marx." Despite the honey bee's painful sting and the stereotype of insects as pests, bees are generally held in high regard. This is most likely due to their usefulness as pollinators and as producers of honey, their social nature, and their reputation for diligence. Bees are one of the few insects regularly used on advertisements, being used to illustrate honey and foods made with honey (such as Honey Nut Cheerios). In North America, yellowjackets and hornets, especially when encountered as flying pests, are often misidentified as bees, despite numerous differences between them; see Characteristics of common wasps and bees. Although a bee sting can be deadly to those with allergies, virtually all bee species are non-aggressive if undisturbed and many cannot sting at all. Humans are often a greater danger to bees, as bees can be affected or even harmed by encounters with toxic chemicals in the environment; see Bees and toxic chemicals. |