Organismal close-up: Introduction to the Honeybee. Origins. Honeybees are eusocial. This means that they have the highest level of sociality in animals. When it comes to the structure of the bee: there is the queen who lays eggs and then the worker bees ( lifetime fitness:0, they dont reproduce) Sociality issue: why are they doing what theyre doing? If they dont reproduce Same mother not the same father Eusocial definition: defined by cooperative brood care (including care of offspring from other individuals), overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. They evolved from wasp-like ancestors ( predetory/carvineous hymenopteras) ( sting to paralize) in the Cretaceous period, about 145-65 million years ago. Also, during this period, flowering plants became dominant in the world’s flora. Therefore, bees and flowers have been coevolving for over 100 million years. Most wasps are solitary Some are social wasps/bees Wasps parallel bees Ants: hypersocial From their wasp-like ancestors, bees inherited their narrow waist, a stinger, and the ability to build nests. The narrow waist permits the abdomen to be pointed in many directions for stinging and laying eggs. Not their abdomen Thorax= first segment of the abdomen Use the narrow poriton of the “abdomen” to be more mobile To sting To lay eggs The stinger, used in wasps to kill or paralyze prey, is used by bees to defend the colony from robbers. However, wasps are predators, whereas bees feed almost exclusively on nectar and pollen gathered from flowers. Flowers provide the complete diet for the bee colony. Evolution of social structure. Most bees and wasps are solitary species in that individual females lay eggs in either burrows or wood crevices. They provision each egg with pollen and nectar (bees) or prey (wasps). Usually each egg with its food is placed in its own “cell”, which is walled off from the adjoining cell. In these solitary species, the bee/wasp mother never meets her children (she leaves them after provisioning the nest). No colony, all individual bees doing their own thing ( solitary species) Early social species. A few burrowing species are social, where the mother waits for the daughters to be born, and then these daughters help the mother forage and dig or form extra cells for her to lay eggs in. These working daughters are the beginning of the “worker caste”. Social→ female will hang out with the mother after being hatched and then work together to do thing like build nests and find food More advanced species, like bumblebees and yellow-jacket wasps: Here the workers are far more numerous (hundreds in bumblebees and thousands in yellow-jackets). The workers are smaller than the mother “queen” (queen caste), and often have different color patterns. Behavior has been partitioned too. Workers forage, build the nest, and defend it. The queen never leaves the nest and only lays eggs. Annual vs. perennial. In the previous examples, the colony is annual, that is, the foundress queen creates workers (and males), and the colony grows until the end of the growing season, when all bees die except new queens that have been inseminated. ( everyone dies except the new queen burried in the soil→ foundress quen) These new foundress queens will overwinter in a burrow or crevice, and in the spring, start feeding and building a new colony. The colony lasts only ONE YEAR If you see a bee fling around in december= that is a queen bee Only in honeybees (Genus Apis) is the colony perennial, potentially living forever. ( 1 colony= 50/80, 000 bees) Two adaptations have permitted this: Honey storage away from the brood combs (developing offspring). Allows honeybees to survive periods of harsh environmental conditions, like winter and droughts. Supplies the energy to heat the colony during winter. Honeybees use the honey to shiver, which creates heat. During drought, nectar flow (flower availability) may stop (called a “dearth”), but the stored honey can be used until nectar flow resumes. What if it gets warm and then cold all of the sudden→ die HONEY→ colony species fully rely on this to get through harsh environmental conditions Colony formation by swarming. In the late spring, large honeybee colonies reproduce by swarming, which splits the colony. Split into 2 in april The other half leaves and gets their own queen The new colony has a mated queen and a lot of workers and is “ready to go”. This is a big advantage over solitary or more primitive social species that must start each spring with a single foundress queen. Bees use honey to get through winter Bee species. Honeybees are members of the genus Apis. This genus is native to Europe, Asia, and Africa (not the Americas). The number of Apis species is debatable, the number varying from 4 to 15 depending on the taxonomic treatment. There are basically 4 distinct honeybee groups: Dwarf Honeybee: Apis florea & other. Only ¼ inch long. Native from Iran through SE Asia. The comb of the nest is small and only contains a few ounces of honey. Open nest The comb is a single small plate. The nest is usually concealed under leaves or in a cave. People do cut these nests down to harvest the honey, but little honey harvest is achieved. Couple ounces of honey Giant Honeybee: A. dorsata. Large bees about 0.7 inches long. Geographical distribution similar to Dwarf Honeybee. In Nepal, Tibet, and India. The comb of the nest is a large exposed plate which is strong and can contain up to 50 lbs of honey. The nest is not in the dark and must be fully illuminated; they usually hang down from tree branches, placed about 80 ft in the air. Ununsual because nests are in the open and not hidden These bees are aggressive if the nest is raided, and will pursue the raider for up to 300 feet. The copious honey is greatly prized by local peoples. Eastern Honeybee: A. cerana & others. Slightly smaller than the Western Honeybee. Wide distribution covering most of Asia. Over this wide range, several races have evolved, for instance an Indian and Burmese race, a Japanese race, etc. Sometimes these are considered species, other times as subspecies. The nest consists of several combs hanging in parallel plates, each plate being separated by a consistent distance (the “bee space”). Found in dark hollow trees and caves. Bee space= very specific value Comb separated by bee space= they will be int hat space only If too far or too close= bees will purpusefully put it back Everyone tries to understand this concept to grow honey easer ( reasons or beekeepers) In less tropical regions, they store a decent amount of honey. Western Honeybee: A. mellifera. The most widely distributed bee on Earth. It has been under human domestication for so long that its origins are unclear. It appears to be native to Africa, and from there it spread into Europe (perhaps 10,000 years ago), and later with colonial expansion into North America and Australia. The nest is like the Eastern Honeybee, with parallel plates and a dark interior. This nesting behavior adapts well to the artificial nests made by humans. With such a wide range, many races have evolved, often recognized as subspecies. Italian Honeybee, Apis mellifera ligustica: Yellow- and orange-banded abdomen. Originally from Italy and Sicily, now the most widely distributed race in the world. There are better choices for cold regions. They are gentle, disease-resistant, and good foragers. Carniolan Honeybee, A. m. carnica: Dusky brown with more muted orange bands. Originally from Austria and the Balkan region. Has been transported worldwide, like the Italian. Second most popular race after the Italian. Often used in cooler northern areas since they fly in cooler weather than Italians. Gentle, disease-resistant, good nest defenders, and make lots of honey. German Black or Dark European Honeybee, A. m. mellifera: A cold-weather resistant race, from western Europe including Britain, and north and west of the Alps. African Honeybee, A. m. scutellata: Native to southern and central Africa. Looks a lot like the Italian. High honey yields, great disease-resistance, and highly defensive. Accidentally released in Brazil in 1957. After release, hybridized with more gentle European races, giving rise to “Africanized bees”. Cape Honeybee, A. m. capensis: From the Cape Peninsula in South Africa. Unlike other honeybees, female workers are able to lay fertile eggs. In areas where the African and Cape races co-occur, the Cape queens can enter the African colonies, undetected, and lay eggs which lead to laying workers, which eventually destroy the colony. The only bees that can have worker bees lay eggs Egyptian Honeybee, A. m. lamarcki: Small and dark with yellow abdominal bands. Native to the Nile valley region. Defensive behavior and low honey production. This was probably the race used by ancient Egyptians. Today it doesnt make as much honey The Buckfast bee: A hybrid bee developed by Brother Adam at Buckfast Abbey in Devon, England, in 1919. The stimulus to create this new bee came from the massive bee losses caused by the Isle of Wight disease, which occurred between 1906 and 1919 on the Isle of Wight in southern England. Brother Adam at Buckfast Abbey noticed that hybrids between Italian and German Black honeybee survived the disease, and so he began an extensive breeding program to create the Buckfast bee, which is a hybrid involving honeybee strains from Italy, England, France, Turkey, Greece, and two African strains. SUMMARY: hybirds of bees (=buckfast bee) did not die due to the disease → highly disease resistant Buckfast bees have many desirable characteristics and are widely available. Castes. Long abdomen on queen= for big ovaries for the kids Bigger shiefd for protection MASSIVE eyes for drone / furry tail A Western honeybee colony or hive is composed of thousands of individual bees. At the height of summer, a hive may contain up to 50,000 bees. Most of these individuals are workers, which are sterile females. A few hundred individuals are drones, which are fertile males. The hive normally has only one queen, who is female and fertile. These bee castes are easy to distinguish with the naked eye. Each caste has its own roles within the colony. Sex & genetics. Of the three castes, only the queen normally lays eggs. The queen becomes fertilized by mating with several drones on her nuptial flight. The queen stores sperm in a special organ (the spermatheca). What determines sex in the offspring? Unlike humans, bees have no sex chromosomes. Haplodiploidy. (diploid= female, haploid=male) It was previously thought that sex was determined by the number of chromosomes in the organism. In haplodiploidy, queens and workers are diploid with 32 chromosomes, and drones are haploid with 16. When laying eggs, the queen makes the decision to either fertilize or not fertilize the egg. A fertilized egg is diploid and makes either a worker or another queen, whereas an unfertilized egg is haploid and will form a male drone. During inbreeding studies carried out by investigators, diploid drones were created, which brought into question the idea that chromosome number alone determines sex. Sex determination locus (SDL). This genetic locus (a physical position on a chromosome) was hypothesized to exist over 70 years ago. At this locus, a diploid bee can have two genes (alleles) present, whereas a haploid bee can only have one gene present. In a diploid bee, if both genes are the same (called a homozygous genotype), the bee is male (diploid drone). If the genes are different (called a heterozygous genotype), the bee is female. In a haploid bee, only one gene is present (called a hemizygous genotype), which results in a male (drone). Complementary Sex Determiner (csd) gene. In 2003, the actual gene for sex determination was discovered. It is called the Complementary Sex Determiner (csd) gene, which has at least 15 variants (alleles). The product of the csd gene (protein) is required for the bee to become female. This protein binds to the mRNA made from a feminizer gene called fem, causing it to function a certain way, leading to a female. If it does not bind, the function of fem will differ, leading to a male. The product of the csd gene will only be able to bind to fem if both alleles at the SDL are different (heterozygous). Workers, basic structure. The worker is the “routine” bee, which is between ½ - ¾ inch in length, with an almost cylindrical body. Workers, like other castes, can see well, have the ability to detect sound, and have antennae that sense the physical and chemical environment. Chemicals called pheromones are picked up by the antennae, and these chemicals are used to control many activities within the hive. Mouthparts. Worker mouth parts consist of mandibles and a proboscis. The two mandibles oppose each other like scissors, and they are used to bite, chew, and hold objects. The proboscis is a tubular apparatus used for sucking up nectar, and to regurgitate the nectar back in the hive. Pollen collection. One major activity of workers is collection of pollen, which is accomplished by the many feathery hairs on the body. When visiting a flower to drink nectar, pollen adheres to the hairs, and the bee brushes the pollen onto the hind legs using legs bearing special stiff hairs resembling a comb (the pollen brush). When the hind legs are rubbed together, pollen is forced into a specially modified joint on the legs, which then presses the pollen mass into a hard cake. This pollen cake is held in place by a fringe of hairs called the corbicula or pollen basket. These pollen masses are easily seen on workers entering the hive after visiting flowers and are the color of the pollen they have collected. Stinger. As is widely known, workers bear a stinger at the tip of the abdomen. It is used to defend the hive. It is modified from the egg-laying ovipositor; therefore, males don’t have a stinger. The stinger is barbed, and when she attempts to withdraw it after stinging a human, it gets stuck and pulls out some of her abdominal organs, the venom sac and a muscular pumping mechanism. The worker will soon die. The stinger will remain in the skin and will continue pumping venom. It will also release alarm pheromones into the air which alarms other bees to pursue the victim. Wax glands. On the undersurface of the bee’s abdomen are located 8 wax glands. In these glands, special cells secrete beeswax, which forms a blob at first, and then forms into a flat scale or chip shape. These chips are about 1/8-inch-long and can often be seen protruding out from below the abdomen. The beeswax is used to build the comb. The bee scratches off the wax from the glands with its legs, and passes it to its mandibles. Beeswax is mixed with saliva and chewed to make it malleable and the perfect consistency for use. Beeswax is an energetically demanding material to produce. How much honey is needed to make a pound of wax is not agreed on, with estimates varying widely. A reasonable value is about 20 lbs of honey to make 1 lb of beeswax. Workers, early development. An egg laid by the queen hatches in 3 or 4 days. The young larva is visited by adult worker bees, called nurse bees. The larva receives over 140 small meals over a span of five days, at which time the larva is fully grown. This is about nine days after the egg was laid. Larval diet. During the first 3 days of the larva’s life, nurse bees feed the larva a protein-rich secretion from their mandibular and hypopharyngeal glands. This substance is called either “brood food” or “royal jelly”. Its protein content comes from the pollen consumed by the nurse bees. After the 3rd day, nurse bees dilute the brood food with honey and pollen, and the total amount of food fed to the larva is reduced. (For comparison, if the larva is destined to become a queen, nurse bees continue feeding the larva brood food in unlimited quantities. The brood food is never diluted with honey and pollen nor is it reduced in amount.) Larva grown, sealed in. Once the larva is fully grown (about nine days after the egg was laid), the nurse bees seal the cell with wax, which is tan in color and somewhat porous. It takes the nurse bees over 100 visits and 6 hours of effort to seal the cell. Inside the sealed cell, the larva transforms into a pupa, and then undergoes metamorphosis into an adult. Emergence. Generally, a worker bee emerges from her pupal cell 21 days after the egg was laid. For comparison, a drone takes 24 days and a queen 16 days. These development times are similar in the Eastern honeybee, possibly because both species regulate the hive temperature to about 95 deg F. A newly emerged worker bee spends a few hours grooming herself until she is dry. Early life as an adult in the hive. Getting fed. For the next few days, she will stay in the nest and “ask” other workers for food. She sticks her tongue out at the passing workers, and they will respond by opening their mandibles, dropping their tongue a bit, and then regurgitating a droplet of sugary liquid from which the new bee drinks (a process called trophallaxis). After about 3 days, the new bees begin to feed on honey reserves in the honey-storage cells, and on protein-rich pollen located in certain pollen-storage cells. Work duties. During days 4 and 5, the bee may start feeding the developing brood. At first, she can only feed older larvae, which don’t require pure brood food, as she can only regurgitate honey and pollen. By day 6, her hypopharyngeal glands start making brood food, so she can then feed the younger larvae. She uses the protein-rich pollen that she has eaten to make the brood food. From days 10 to 12, her brood food glands are exhausted, so she stops feeding the larvae. Her wax glands start making wax, so she begins making and repairing comb. Workers, adult development. Figure. Consecutive flights of five individual bees. (a, b, c) Consecutive orientation flights of three bees. (d, e) Complete orientation phase before the first foraging flights (FO) of two bees. Venture out, orientation. Also, from days 10 to 12, she will leave the hive for the first time. On her first trip outside, she will defecate for the first time. Orientation. At first, she hovers near the hive to learn the environment around the hive. These are called orientation flights. Circling pattern, with ever-wider circles. Later, she will fly further away. Meeting foragers, making honey. For the next week or two she will stay mostly in the hive, meeting the incoming forager bees. These foragers come into the hive with a full honey stomach and pollen load, and when she meets them, they will regurgitate the liquid and pass it to her (she drinks it). She will take it deep within the hive and regurgitate it, then swallow it, and repeat. As she does this, she partially digests the sucrose in the nectar into fructose and glucose (using the enzyme invertase). This manipulation of the liquid also dries it down to 17-18% moisture, which is extremely concentrated. The final product is honey, which is then deposited into honey-storage cells. Drying of the honey is also aided by the other workers that continually fan their wings to create a draft. She also places the pollen load from the foragers into the pollen-storage cells. Workers, housekeeping, graduation to foraging. Also, during the first weeks in the hive, she will do general housecleaning, like removing debris and dead bees. Observing older foragers. By week 3 or 4, she becomes a forager, and starts off by closely observing the returning older foragers. She especially observes the scout foragers that found new sources of pollen and nectar. These scouts perform communication “dances” that tell the other foragers where the food is located. It takes the new forager time to learn the language of the dancing. Once she figures it out, she will join the foraging force. Foraging duties. When foraging, she is focused primarily on collecting nectar and pollen. But she also will drink water and collect propolis, which is a sticky sap exuded by trees. Propolis is used in the hive to seal gaps and holes and to improve the strength of combs. Guard bees. A small number of bees will become guards, which stand near the hive entrance with their front legs held off the surface, making them look like they are going to pounce. They guard the entrance against non-hive bees and honey robbers. Retirement (death). During summer, she works so hard that she dies within 5 or 6 weeks from emergence. If she emerged in the fall, her activities are far more restricted, and she could live for 5 or 6 months. Workers, communication. Foragers can communicate the presence, direction, nutritional value, and distance to food sources by “dancing” on the comb surface and regurgitating the food. Food is close by. If the food source is within a few hundred feet of the hive, the forager will do the “round dance”, where she moves in circles, alternating between clockwise and counterclockwise directions. The other workers pay close attention to the dance. The forager is covered with scents from the food source, and the other bees will leave the hive in search of matching odors. Food is far away. If the food is further away, the “waggle dance” or “figure-eight” dance is performed. Here there are two circles, one clockwise and the other counterclockwise, with a straight line connecting them. The straight line portion contains several clues: The angle of the line relative to the vertical axis of the comb represents the angle of the sun relative to the food source. The length of the line represents the distance. The intensity of waggling back and forth suggests the quality of the source, with greater waggling corresponding to greater quality. Since the hive is totally dark inside, the observing workers cannot see the dance but instead sense it by vibrations and probably by other means. Workers will press their abdomen to the comb and vibrate signals back to the dancer, and she will regurgitate some of the food for the workers to sample. When traveling to the food source, the foragers can detect the sun’s position in the sky even on overcast days. Queen, basic structure. The queen is longer and narrower than the worker. She is up to ¾ inch in length. Her head and eyes are smaller in comparison to the workers, because she does not forage outside the hive. She has a very short tongue because she never sips nectar from flowers, but is fed directly by her “attendants” (a group of worker bees, also called a “retinue”). Her mandibles are also different, and associated with them are large mandibular glands, which secrete the “queen mandibular pheromone” (QMP) or “queen substance”. (Workers also have these glands, but they don’t secrete QMP.) Her abdomen is long because it contains many eggs. Her legs are not adapted for pollen combing and holding. She has no wax glands. She has a stinger, however it is not barbed like the worker stinger. It is only used for one purpose: killing rival queens. Queen, pheromone. QMP is a complex mixture of chemicals, with only about 24 of them being well known. The queen is constantly attended by her “attendant” workers, which monitor, lick, groom, feed, and exchange body fluids with her. As a result, the attendants pick up the pheromone. The attendants then spread the pheromone to other workers. Within the hive in general, each bee is frequently exchanging fluids and food with other bees, so the pheromone gets spread among all bees in the hive. The presence of QMP is how workers in the hive know that the queen is present. If the queen secretes normal levels of QMP and the hive is not overly crowded, each worker in the hive feels “queenright”, that is, a normally functioning queen is present. If levels of QMP in the hive drop because the queen is not producing enough, the workers will begin preparations to make a new queen. This is termed supersedure. Also, if the number of workers in the hive gets too large, the QMP will get diluted so much that each worker no longer feels “queenright”. This may lead to swarming behavior. To prevent swarming, each worker needs a daily QMP dose of about 0.001 mg. QMP is how the queen exerts her control over the hive. It: Suppresses ovary development in the workers. Therefore, normally workers cannot lay eggs. More about laying workers: If QMP levels drop too much or the queen dies or is removed, ovaries in the workers will develop and they will begin laying eggs. This leads to only drone offspring (because workers are not inseminated and cannot fertilize the eggs), which quickly leads to the death of the hive (unless corrective action is taken by the beekeeper). It is believed that in every colony a few workers are regularly laying eggs, but the prevalence of this is very, very low. See information on the Cape Honeybee (later lecture), where laying workers and clonal offspring can be common. Prevents workers from making new queens. Stimulates foraging and brood rearing. Attracts attendant workers. Helps keep the swarm together when the queen leaves the hive during swarming. Serves as a mating attractant for drones during her nuptial flight. Maintains the general “morale” of the hive. Lack of QMP makes the bees nervous and agitated. Queen, reproduction. Normally, the queen is the only bee in a hive that lays eggs. Eggs are laid singly at the bottom of a cell in the comb. During summer, a healthy queen can lay 1,500 eggs per day, which is more than her body weight. In one year, a queen can produce 200,000 workers. Queen, development. Queen development is very similar to worker development, with a few exceptions. As stated previously, during the first three days of the larva’s life, it is fed brood food. After that, nurse bees continue feeding queen larvae the brood food in unlimited amounts until the larva is fully grown (nine days after the egg was laid). The cell in which the queen develops is very large and peanut-shaped. It is called a “queen cell”. Workers construct this large cell in preparation for making a queen. So much brood food is fed to the larva that the cell fills with it, appearing as a milky white fluid. The queen emerges from the cell 16 days after the egg was laid. Queen life span. On average, queens live from one to three years. But queens can: “Wear out” and produce insufficient QMP. Have their QMP diluted by the hive getting too crowded. Can die or be removed from the hive. All of these fates will stimulate the workers to create new queens (if they have eggs or young larvae to work with). If a queen makes insufficient QMP or the hive is too crowded, workers will gradually make queen cells. If a queen dies or is removed, workers detect her absence within hours and start making queen cells. Queen death in new hive. A new colony with an unmated or poorly mated queen (and therefore no eggs, larvae, or brood) is vulnerable to failing. Such a colony might result from a swarm or from installing a new package of bees into a hive box. The queen embarks on mating flights and hopefully gets successfully mated and returns to the hive. But what if she is killed on her flight (by a bird, dragonfly, etc.)? The colony is doomed because the workers lack the eggs or young larvae from which to make new queens. Workers will eventually start laying eggs, leading to all drone offspring and death of the colony. (A beekeeper who notices this within about two weeks could simply install a new queen that has already been mated.) Queen cells. Queen cells are large, peanut-shaped cells found on the comb face, comb edges, and comb bottoms. There are three types: Emergency. When a queen is killed (or removed by a beekeeper), the workers create these cells from pre-existing cells containing eggs or young larvae. They remodel the cell to fit a developing queen. Such cells may be smaller than the other two kinds of queen cells. Swarm. Under crowding (or other) conditions, workers will gradually create swarm cells, usually many in number, and generally hanging off the bottom of the comb. Swarm cells in the hive tend to be of varying ages. Supersedure. The workers detect that something is wrong with the queen, and they work to replace her by making supersedure cells. A hive usually has two of these cells placed on the face of the comb, but the number and position can vary. The supersedure cells tend to be of the same age. Queen replacement. For the workers to create a new queen, the hive MUST have eggs, or larvae that are no older than three days. If they are older, they will have been fed diluted brood food and be on their way to forming workers. If the original queen is failing or gone, and there are no eggs or three-day or younger larvae, the hive is doomed. All current larvae are on the path to becoming workers, and no queens can be made. Without a queen, no eggs are laid, therefore no brood are made, and within about six weeks all workers (and the hive) will be dead. Queen, birth/regicide/insemination. Virgin queen emerges. When the adult queen chews her way out of the queen cell, she is now a “virgin” queen. Usually, before a virgin queen emerges, the old queen in the hive will leave with some of the workers, forming a swarm. Therefore, the new virgin queen should not encounter a mated queen in the hive. Regicide. Generally there are several other queen cells in the hive. Once the first queen emerges, she is groomed and dried by her attendants. She then seeks out all other queen cells in the hive, tears open the cells with her mandibles, and stings the other queens, queen larvae, and queen pupae to death. Workers can block it. Sometimes, workers will prevent the first-hatched queen from killing the other queens. Workers line up and block her. In this case, the workers want several queens to emerge, and for each to leave with their own swarm. See section on swarming. Nuptial flight. The virgin queen then exits the hive on her “nuptial flight”. She seeks out groups of drones that have gathered at tree tops or other elevated locations (“drone congregation areas”, covered later). The queen and drones locate each other visually and chemically; drones release attractant pheromones, and the queen releases QMP. Once the drones detect the queen, they follow her and attempt to mate for about 30 minutes, and they may fly several miles during this time. Insemination. Drones approach the queen from below, and grasp her abdomen with their legs. The drone inserts his endophallus (a penetrating organ of his genitalia) into the queen’s sting cavity. He then releases his grip and allows his body to flip backward. This body flexing compresses his abdominal organs, which causes an ejaculation of sperm into the queen. The endophallus then snaps off of his body (with an audible “snap”), and he falls to the ground and dies. After mating, the endophallus protrudes from the queen’s abdomen and is termed the “mating sign”, a clear indication that she is no longer a virgin. This mating sign is thought to serve as a sort of plug preventing the sperm from leaking out of the queen. Additional drones can then mate; the mating sign is structured so that a subsequent drone’s endophallus can easily dig out the mating sign and some of the previous drone’s sperm. Once the queen returns to the hive, workers will remove the mating sign. After mating, the queen will begin laying eggs in three or four days. Drones, basic structure. Drones are male. They are larger than workers, about ¾ inch long. They are also much heavier and robust, and hairier. The eyes of a drone are huge and cover most of the head, meeting at the top of the head. Like the queen, the drone does not forage, build the nest, rear brood, or defend the hive. As such he lacks a long tongue, pollen basket, wax glands, and stinger. The purpose of a drone is to locate and mate with a virgin queen. Drones, development. In general, there are no drones in the hive during early spring. Worker bees decide when it is time to make drones, and will construct special drone cells that are larger than normal worker cells. These drone cells are often built at the edge of the comb, and are easy to see because the wax cap protrudes out from the comb surface like the tip of a bullet. When the queen detects these larger cells, she lays a single unfertilized egg in them, resulting in a drone. By mid-summer, there can be hundreds of drones in the hive. Similarities and differences to worker development. Timing of the larval development is similar to the worker, and it is fed the same diet as a worker. The main difference is that it takes 24 days from the egg for an adult drone to emerge from the cell. (For comparison, the worker takes 21 days.) Drones, activity. Drones live within the hive for their first couple of weeks of life, and then start making afternoon flights from the hive. They fly very fast, and join up with drones from other hives to form a “drone comet”, which flies through the neighborhood, visiting certain sites frequently. Drones release “drone pheromone” which attracts other flying drones, which promotes drone congregation. These sites are called “drone congregation areas”, and are often the tops of certain trees or a certain edge of a certain forest. Year after year, drones congregate at these same areas. It is thought that these areas are conducive to mating success. Drones only live a short time, and no intergenerational learning is possible, so how they know to visit these places every year is not understood. As previously stated, the drones give off attractant pheromones to attract the queen. Likewise, the queen’s QMP attracts the drones. Drones, life span. Drones cannot feed themselves, so are totally at the mercy of the workers. If he never gets the chance to mate, the workers commit fratricide. By late fall, when the hive is preparing for winter, workers push the drones out of the hive to starve. Drones are not useless in the hive; they assist in hive temperature regulation. Drones are one way that a colony can send its genes out into the world. Colony reproduction. Swarming is the natural means by which new honeybee colonies are created. It usually occurs in early spring, just before or during the main “nectar flow” (availability of pollen and nectar in the environment). This timing allows the new colony to have ample time and resources to build a new comb and rear brood. When the density of bees in the colony reaches about 36 bees per cubic inch, preparations for swarming begin. As previously stated, dilution of QMP is likely the reason. There are probably other reasons too. Process of swarming. Preparations. Queen cups and cells, egg laid. Preparations begin several days before the actual swarm occurs. The workers start with the construction of queen cups, which are large, wide cell bases usually constructed at the edge of the comb. These cups are then lengthened to form the queen cells (swarm cells), which are spacious. The cells are vertically oriented, and usually near the bottom of the comb. They appear as inch-long, dimpled, peanut-shaped swellings to the beekeeper. The queen lays fertilized eggs in these queen cells. When they hatch, the workers feed the larvae copious brood food in unlimited amounts for about 8 days, at which time the cells are capped with wax. Once the queen cells are capped, the hive is on the pathway to swarming and preventing it is very difficult. Scout bees. A few days prior to swarming, scout bees examine the environment for suitable new nesting sites. These scouts are experienced foragers that know the local area well. Conditioning the old queen for flight. During the swarming, the old queen must fly. Remember that the last time the queen flew was during her nuptial flights. The old queen is bloated with eggs and too heavy to fly, so the workers put her on a “diet” to thin her down so that she can fly again. Workers feed her little and chase her around for exercise. The old queen will greatly slow down her egg laying during this conditioning phase. Changes to worker behavior. Workers engorge themselves with honey. (Why? They will need that energy to build honeycomb at the new colony location.) Foraging activity stops temporarily. Swarming begins and ends. When the swarm begins, the old queen and 10,000 to 20,000 workers leave and fly as a mass, led by the scout bees. The speed of the swarm varies from about ½ - 6 mph, and its shape usually starts off spherical and eventually becomes egg-shaped as it moves. Back in the original colony, the new queens have not yet emerged. Commonly, the swarm will find a resting place on its way to the new nest site. Such a resting swarm is a large and noticeable object (it is during this resting phase that a beekeeper can capture the swarm). A swarm hanging temporarily on a tree branch (for example), is a large mass of workers (with full bellies) surrounding the old queen. Swarms are known to be gentle, since a full honey stomach prevents bees from stinging. If the swarm sits long enough to use up its food it can become aggressive. (The “bee beard” worn by beekeepers is a swarm.) Scouts will urge the swarm onward to the nesting site, and to guide them there, they release Nasonov pheromone from their Nasonov gland at the tip of their abdomen. The swarm is attracted to this pheromone. (Nasonov pheromone is also used at the entrance of the hive to help foragers find the entrance, and it is placed on flowers to guide other foragers to the flowers. A bee releasing the pheromone will raise its abdomen in the air and expose the gland, and then fan its wings vigorously.) Upon arrival at the new site, workers begin construction of the new comb. Recall that workers can make a lot of wax because they engorged themselves on honey before leaving the old hive (equal to about 40% of their body weight). (Like a 170 lb. man eating 68 lbs. of honey.) In a few days, the comb is usable and the queen begins laying eggs to establish the new colony. Occasionally, a swarm will not find a new site and will build an open-air colony. Back in the original colony. The original colony is termed the parent colony. Swarm cells begin to hatch, regicide or not. The first queen to emerge is a virgin queen, and is therefore skinny and is not too different in size from the workers. She seeks out and destroys the other virgin queens that are developing. The virgin queen will then take her orientation flights, then her nuptial flights, get mated to usually about a dozen or so drones (in a drone congregation area), and then return to the colony and begin to lay eggs. Prevention of regicide. Sometimes, workers prevent the virgin queen from killing the other virgin queens. In this case it is believed that the workers sense poor conditions for swarm success (that is, likely low success in setting up a new colony), so they allow multiple swarms to issue from the parent hive to increase the chances that a new colony will establish. These are usually called afterswarms. The first hatched virgin queen will leave with a small afterswarm, and then the next hatched virgin queen may leave with yet another afterswarm, etc. At some point a final virgin queen resides in the parent hive. Each afterswarm issued by the parent hive is small and they get smaller and smaller as the workers in the parent hive are used up.

What is the fundamental concept in economics that describes the relationship between availability and consumer desire for goods or services?

Supply and demand.

What happens to prices when demand exceeds supply?

Prices tend to rise.

What occurs when supply exceeds demand?

Prices tend to fall.

How does the concept of supply and demand help in understanding market behaviors?

It provides insight into pricing strategies and economic contexts.

What is the fundamental concept in economics that describes the relationship between availability and consumer desire for goods or services?

Supply and demand.