2. Bees: The Individual and the Colony
The first step in studying bees is to learn as much as possible about their biology. This information about their life and needs is required to manage and maintain the colonies properly. It is even more important when you must diagnose an ailing colony that may have lost its queen or become infected with disease.
Kinds of Adult Bees
The honey bee colony includes both male and female bees for only a portion of the year. The males, or drone bees, are normally present in spring and summer. Female bees, the queen and her workers, are present all year. Naturally, all three types of individuals are important to the colony and to the survival of the species.
The beginning beekeeper needs to learn to recognize these different bees as quickly as possible. They are shown together in Figure 1. Close observation, repeated at frequent intervals, will make it easy to distinguish the two sexes and the two female castes. (All specialized terms are defined in the Glossary.) The workers are the smallest bees in the colony. Their abdomens are pointed at the end but may vary somewhat in length. The abdomens of workers with full honey stomachs are longer than those of workers carrying little food, but they are always shorter than the queen's abdomen. Before the young queen mates, her body is similar in appearance to a worker's, except that its overall size is noticeably larger. As she begins to lay, the queen's abdomen becomes greatly elongated, so much that her wings look short. They cover only about two-thirds of her abdomen. In contrast, the wings of both workers and drones nearly reach the tip of the abdomen when folded. Queens' and workers' large, compound eyes are separated by areas of hair in which their three, small, simple eyes, called ocelli, are located. Drones have large, stout bodies with blunt abdomens. A conspicuous brush of hairs is visible at the end of their abdomens. This character is not present on the female castes. The drones' large, compound eyes can be easily distinguished from those of the other bees because they are the largest and they meet on top of the head. The drones' ocelli are located below the compound eyes, close to the antennae.
The three kinds of adult honey bees. The worker bee is at the top left, the drone is below the worker, and a marked queen is the large bee at the right. (Fig.1)
The worker bees (Fig. 2) are the largest group of bees in the hive up to 60,000 in midsummer. They develop in the smallest cells in the comb of the colony from fertilized eggs laid by a queen. They are imperfect females and under normal hive conditions they do not lay eggs. The young, grublike or wormlike larvae receive large quantities of food that surround and support them for the first few days after they hatch from the egg. As the larvae grow, they consume all the excess food. The nurse bees then feed them small quantities of food at frequent intervals. About 5 days after hatching, the larva is sealed in its cell where it spins a partial cocoon and begins the body changes, or metamorphosis, that produce the pupa and finally the adult worker bee. The cell capping on worker cells is flat or only slightly convex. There are about 55 worker cells to the square inch, including both sides of the comb.
A worker bee (Fig. 2)
From 19 to 22 days after the egg was laid, depending on conditions in the hive, an adult bee emerges from the comb by chewing a hole in the capping of her cell. She is soft and downy, and is not yet capable of making wax, stinging, or flying. She will spend more than half her life doing hive duties in a rather flexible sequence that is governed by the colony's needs. Usually this begins with cleaning cells and feeding and caring for the brood (the immature stages of bees) (Fig. 3). Other typical duties include building comb, removing debris, and guarding the entrance (Fig. 4). Although we think of bees as being very industrious, the workers spend many hours patrolling the hive and sitting idle on combs. The patrolling probably serves to inform bees of the needs of the colony and also produces heat to maintain the warmth of the brood nest where the young bees are reared.
Young workers begin to fly from the hive when they are 10 to 20 (lays old, and in some cases even earlier. At first they take short flights in front of the colony, often on warm afternoons. These flights acquaint the bee with the appearance of the hive and its immediate vicinity. The term "play flights" has been given to this activity because the bees bob and weave in the air while facing the hive.
Workers forage first for either pollen or nectar. They may change from one to the other but usually collect pollen first and nectar later. The nectar collectors may also collect water when the colony needs it, and a few bees collect plant resins called propolis or bee glue.
Workers live 4 to 6 weeks during the active season. Those reared in the fall may live as long as 6 months, allowing a new generation to develop in the spring before they die. These differences in length of life have not been completely explained, but they are probably brought about by changes in glandular activity, diet, and the amount of brood reared by the colony in the fall.
A young worker bee feeding a larva. (Fig. 3)
Worker bees on guard at the hive entrance. (Fig. 4)
The colony uses large quantities of honey and pollen as food, but the bees usually store more honey than the colony needs. Only this surplus production should be removed by the beekeeper (see page 79). The young worker bee needs pollen to develop the glands that are used to make the secretions fed to developing larvae and to the queen. Adult bees can survive without pollen, but they are soon unable to rear young bees. Wax is produced by glands on the underside of the abdomen of house bees. It is secreted only when the colony is obtaining considerable quantities of nectar or is being fed sugar or honey by the beekeeper.
The male bees, or drones, appear in the colony in late spring (Fig. 5). No certain number is produced and colonies may have only a few hundred or as many as several thousand. They help to produce heat in the colony and may be of value by affecting the "morale" of the colony or in other ways that are still not known. However, since they consume food and take up space, their numbers should be kept at a minimum. Colonies allowed to build combs without foundation or to repair dam- aged combs will produce large numbers of drone cells as well as worker cells. You can reduce drone production by using full sheets of comb foundation and by culling combs with large areas of drone cells.
The drone. Note the blunt abdomen and the eyes that meet on the top of the head. (Fig. 5)
The drones are produced from unfertilized eggs usually laid by a queen but occasionally by workers whose ovaries have developed (laying workers). A normal queen lays drone eggs in cells that are larger than worker cells. When sealed, the cells have distinct, rounded cappings (Fig. 6). Both laying workers and queens unable to lay fertilized eggs produce drones in worker- sized cells. Those that complete their development are normal, small drones, but many of them do not survive to maturity in the smaller cells. Drones require from 24 to 25 days to develop from egg to adult.
Another type of drone is produced in some honey bee colonies. However, they are never seen as adults because the worker bees remove them from the comb a day or two after the larvae hatch. These drone larvae hatch from fertilized eggs that have a matching pair of hereditary factors called sex alleles. The eggs are laid in worker-sized cells by a queen that mated with one or more drones having a sex allele the same as one of hers. Eggs with a single allele are unfertilized and usually laid by the queen in large cells of the comb where they produce normal drones. Fertilized eggs with two different sex alleles produce normal worker bees.
The production and loss of these drones, called diploid drones, is detrimental to a colony because as many as half of the fertilized eggs do not produce worker bees. The colony fails to develop the large population needed for honey production. A spotty brood pattern when no disease is present may indicate this problem, and the colony should be requeened.
Young drones are fed by workers for the first few days of their lives. After that time they help themselves to the stored honey and fly in search of queens on warm afternoons. Drones are attracted to certain small areas, at a considerable distance from their hives, where they congregate and patrol while flying 30 to 50 feet above the ground. It is here that they usually meet and mate with queen bees.
When flowers cease to provide nectar for the colony, either in the fall or, more rarely, at any time of the year, the workers no longer tolerate the drones. Workers remove developing drones from the comb and begin to harass the adults, the oldest ones first. The drones are rarely stung but they are pushed and pulled so much that they have difficulty eating. Ultimately, all the drones in a queenright colony are driven from the hive and die. The Italian race tolerates them longer than the Caucasians, and queenless colonies allow them to stay for an indefinite period.
Worker bees on sealed brood. The worker cells are at the top left and the drone cells at the bottom right. (Fig. 6)
The queen (Fig. 7) is responsible for all the qualities of her colony. She mates with several drones and stores their spermatozoa within her body. These drones die, leaving the queen as their representative within the colony. The workers share the queen's motherly duties by caring for the young, but her genetic, or hereditary, makeup and that of the drones she has mated with determine the size and temper of the colony, the color of the workers and drones, disease resistance, honey-producing ability, and all the other characteristics of the colony.
Queens develop from fertilized eggs or from young female (worker) larvae not over 3 days old. In a colony that wants to swarm or needs to replace a failing queen, the old queen lays several eggs destined to become new queens in special cells, or cell cups, that hang vertically on the comb (Fig. 8). Worker and drone cells lie on a horizontal plane. When an old queen is lost, killed or removed from a colony, the bees can produce a new queen from any worker larva not over 3 days old. To do this they modify the worker cell containing such a larva so that the queen develops in a vertical cell similar to those built from queen cell cups. Several queens usually are started at the same time. Regardless of the method by which she begins her development, the young queen larva develops much like a worker but does so more completely and more quickly, in only 15 to 17 days. She receives glandular secretions, called royal jelly, in excess quantity throughout her life. Queen larvae float in a bed of food. This greater quantity of food, together with other differences in quality and content, brings about the differences between worker and queen bees, and produces a queen that is a per feet female with a complete reproductive system.
When she emerges from her cell, the young queen is practically ignored by the workers. Very quickly, however, they are attracted to her and begin to feed and groom her. They even bite and chase her within the hive during the first few days. After about a week the queen is agile and physically ready for her mating flight. She leaves by herself, usually between noon and 4 p.m., and probably flies a considerable distance from the hive. It seems likely that queens visit drone-congregation areas because they mate with many drones in a short period. The average queen makes more than one mating flight and mates with as many as 10 different drones. This system of mating reduces inbreeding and thereby increases the efficiency of the colony.
The mated queen begins to lay a few days after completion of her flights. Her egg production increases rapidly to as many as 2,000 eggs per day. This high output, equal to the queen's own weight, is made possible by the high- protein diet of glandular secretions provided in large quantity by the worker attendants.
Queens lay eggs in greatest numbers in the spring and early summer. They gradually cease to lay in the fall and do not begin again until January or February. Winter brood rearing is normal and takes place in most colonies that have adequate stores of honey and pollen and a good population of worker bees.
Queens may live as long as 5 years but are most productive during the first 2 years. A common cause of failure is inadequate mating that results in the production of too many drones when the queen is unable to fertilize the eggs she lays in worker cells. At that time the colony usually tries to replace her by a process called supersedure. An old, failing queen and her young daughter may continue to live and lay eggs in the same colony for a considerable period.
Honey bee queen, marked on the thorax. (Fig. 7)
Queen cell cup being prepared by worker bees. (Fig. 8)
Length of Development
The three kinds of honey bees undergo the same type of development, known as complete metamorphosis. Each one takes a different length of time to develop as follows (In days):
| ||Queen ||Worker ||Drone |
|Egg is laid ||0 ||0 ||0 |
|Egg hatches ||3 ||3 ||3-5 |
|Cell is capped ||7-9 ||7-9 ||9-10 |
|Adult emerges ||15-17 ||19-22 ||24-25 |
The Races of Bees
Throughout the world there are many races of bees that have developed slightly different body characteristics, biology, and behavior. In the United States two races of bees are most common - the Italian and the Caucasian. The Italian bees have yellow or brown bodies with varying numbers of dark bands toward the end of their abdomens. They tend to raise young bees early and late in the year and need more honey for maintenance than do the dark races. The Caucasian bees are black with gray bands of hair. They conserve their honey somewhat better and use more propolis than the Italian bees. Both races are usually gentle and the bees are quiet on the combs. Carniolan bees are a dark race with characteristics somewhat similar to the Caucasians.
The honey bees available in the United States are the result of crossing and selection of bees from many different races in addition to those mentioned above. Beekeepers should try queens from different queen breeders to learn more about the behavior and honey production of different strains of the same race. Most strains are gentle when handled under the proper conditions. If you have bees that are not gentle, requeen them immediately with a queen from a gentler strain. There is no relation between temper and honey production.
Social insect colonies, including honey bees, have often been regarded as a single superorganism because groups of individuals appear to serve the functions of organs, and the colonies undergo changes as a group that compare with the lifetime development of an individual. To understand and manage honey bees you must be familiar with the development and activities of the colony, and the seasonal changes that take place in it.
The brood nest, where the queen lays eggs and young bees are reared, is the heart of the colony. It may be only a small circle of cells on one side of a comb, or it may include up to 20 or more full combs (frames). The areas occupied by brood on individual frames are usually oval or circular. The entire brood nest, including all the areas of comb containing brood, is generally ellipsoidal or spherical so that it is readily surrounded by the cluster of adult bees in cool weather. The bees form such a cluster when the temperature drops to about 57 degrees F. (14 degrees C.). The area containing developing bees, but not the rest of the hive, is kept at a temperature of about 95degrees F. (35 degrees C.). The worker bees warm the brood nest to this temperature by moving their bodies and fanning their wings, activities that require honey as "fuel." In hot weather the bees cool the nest to 95 degrees F. (35 degrees C.) by fanning to evaporate dilute nectar or water present in the brood nest.
The bees store pollen, their protein food, in the cells immediately surrounding the brood (Fig. 9). In this location it is near at band to be fed to developing larvae and to be eaten by newly emerged adult bees. Tile nectar and honey are stored beyond this band, or shell, of pollen.
A comb with sealed brood in the center surrounded by a ring of light colored pollen. Outher cels of the comb contain honey in open cells. (Fig. 9)
In the fall, the brood nest and the majority of the bees are in the lower combs of the hive. The honey for winter food is above them and there must be pollen stored within the cluster area for winter use. This pollen and the developed food glands of the workers serve as a protein reserve for the colony until fresh pollen is available from springblooming plants. During the winter the bees in a hive of adequate size (at least two deep ]live bodies) move upward as they gradually cat the stored honey. In early spring the brood nest is most often in tile top part of tile hive with empty combs beneath it. If nothing is done to change this arrangement, the bees will slowly occupy the lower combs, and the queen will expand her laying to all areas of the hive. However, the direction of natural expansion is upward.
Theoretically, one set of 10 deep combs is sufficient space for a prolific queen. In practice, 18 or 20 combs in two 10-frame hive bodies provide more suitable conditions for a large brood nest, perhaps because it can be more nearly spherical, rather than flattened as in a single hive body. The colonies need additional room for their rapidly increasing number of adult bees by late April or early May in central Illinois, or about the time of fruit tree and dandelion bloom. The nectar and pollen gathered from such plants may contribute to the crowding. The bees continue to store pollen near the brood nest and honey in the combs above it throughout the season. Without sufficient comb space, the workers gradually fill the cells of the brood nest with honey. This is highly desirable in the late summer to provide food for winter, but it is harmful earlier in the season when tile greatest possible number of cells is needed for rearing young bees. The crowded brood nest restricts the queen's laying.
Worker honey bees have abilities that allow them to accomplish tasks that many other insects cannot do. They recognize several different regions of the color spectrum including near ultraviolet, which man cannot see. However, they cannot distinguish red from shades of gray and black. Honey bees detect polarized light and use it for orientation when foraging. Their senses of smell and taste are highly developed for most materials that are biologically important to them. They readily detect differences in concentrations of sugar solutions and distinguish minute differences in the components of mixtures of odors or solutions. Field bees learn the location of their hive and the appearance of landmarks around it. They also learn the daily movement of the sun in the sky and compensate for it when using tile sun for orientation. Worker bees have a time sense, with a 24-bour base, that allows them to visit flowers or artificial food sources at the times when nectar and pollen are being offered. They can learn to associate a food reward with a flower scent after only one trial. Learning to associate color time, and form (shape) with food takes 3 to 40 trials.
The honey bee colony has a simple system of communication that contributes to its success and adaptability. The system is based on the exchange of food among members of the colony (Fig. 10) and on odors released in and outside of the hive. The queen's glands secrete attractive substances and odors that are removed from her body and shared by the workers of the colony. The materials keep the colony together and prevent the workers from laying eggs and building queen cells. However, if there is an insufficient supply, or if it is not distributed evenly in a crowded colony, the bees construct queen cells to produce a new queen. Odors secreted by workers are used to attract other bees and to alert and alarm the colony. The fruity odor of the scent gland causes bees to cluster when swarming. It is also used when workers rediscover other bees, a queen, or the hive entrance after a period of confusion. Disturbed and injured bees secrete a volatile material known as isopentyl acetate that smells like banana oil. It attracts and excites bees and prepares them to defend the colony by stinging the cause of the disturbance.
Worker bees exchange food on a comb containing honey. The two bees in the center are responding to smoke by eating honey from open cells. (Fig.10)
A more complex means of communication may be present in the elaborate system of movements performed on the combs by bees when they return to the colony after collecting nectar and pollen. These movements, usually called dances or the "language" of the bee, contain information about the distance and direction of the food source from the hive. They may also contain information about the quality, or sugar concentration, of the nectar. Although the idea of a bee language has been widely accepted, many scientists and nonscientists still do not agree that the language theory satisfactorily explains how bees recruit others to a food source. There is agreement that the movements contain information because it has been thoroughly decoded. But if there is truly a sophisticated language, it should bring recruits quickly and accurately to new food sources tinder a variety of conditions. Instead, the percentage of success is often low, the time in flight is far longer than needed for direct flight, and many bees fly the opposite direction from the food.
An alternative explanation proposes that odors of the food and of the aerial flight paths of foraging bees flying to it are used by newly recruited bees in finding food sources for the first time. This idea is supported by observations that few bees can be recruited to all odorless food source although foragers already visiting the food perform more frequent and vigorous dances in the hive than they do when collecting scented foods. More new bees, rather than fewer, should reach the food if the dances are the primary means of directing prospective foragers to a food source.
Two other observations bring the language theory into question. One is the effect of light wind, which does not interfere with flight, on foraging success of recruits. They do not find downwind food sources as well as ones upwind, indicating that odors borne by the wind outweigh the importance of information they receive from dancing foragers. Even a change in the number of bees visiting a food source from one colony can affect the success of recruits from another colony in finding the same source. When fewer bees from one colony fly to the food, fewer new recruits from a second colony are able to find it. Bees using a language should not be affected in this way. However, if the recruits are using the flight path to the food, such a path would have a weaker odor trail when fewer bees were flying along it.
It is natural, but not necessary, to relate the foraging success of honey bees to their use of a sophisticated language. Some stingless bee species use food odors and aerial odor trails and are even better able to exploit food sources rapidly than are honey bees.
One question commonly asked about the dance language is, "Why does the information exist if it is not used?" Similar information is present in the movements made by solitary moths after a flight. These movements continue for a period of time proportional to the distance the moth flew, yet there is no other individual that makes use of the information.
These controversial ideas are presented here to demonstrate that we do not know for certain all the facts about the activities of honey bees. More research is needed on the subject.
A communication system similar to the one bees use to find food is used to select a new home for a swarming colony. However, the relative importance of odor, flight paths, and "language" has not been fully clarified. Scout bees visit available cavities, such as a hollow tree, cave, or hole in a building, and evaluate their suitability as a home for the swarm. After many visits, the bees agree which one is best and move to it as a group.
Bees make honey from several different sweet fluids that they collect from plants. Nectar, secreted by the nectaries, or glands, of flowers is the most common raw material, but some of it also comes from glands located on the leaves and buds of plants. This is called extrafloral nectar, and the glands are known as extrafloral nectaries. Honeydew is another sweet fluid that bees use to produce honey. It is surplus plant sap excreted by plant-sucking insects such as aphids and scale insects. Honeydew honey, called forest honey in Europe, is a wholesome product except when it is contaminated with mold or fungus organisms that darken it and lower its quality.
Nectar-collecting bees make trips ranging in duration from a few minutes to 3 or 4 hours. An average trip probably takes about an hour, and a bee may make as many as 10 trips per day. In order to get a full load of nectar, a bee may visit only one flower, such as that of saguaro cactus, or several hundred flowers, such as those of white clover. The nectar is carried back to the colony in the honey stomach, or honey sack. This is a storage organ in which no digestion takes place. It is controlled by the bee so that she can either regurgitate its contents or allow them to pass into her digestive system. She adds enzymes and waterlike secretions to the nectar from glands in her head. Nectar also contains plant enzymes, and honeydew includes enzymes of insect origin.
When the bee returns to the colony, she passes her load of nectar to one or more young house bees and returns to the field. The house bees do the primary job of processing the nectar into honey. This consists of repeatedly regurgitating droplets of the fluid onto the tongue held beneath the head. The bee continues this activity for 15 to 20 minutes, adding more glandular secretions and reducing the water content of the nectar. The resulting, partially ripened honey is placed in cells in the comb where it loses more moisture to the air circulated through the hive by fanning bees. When nectar is coming into the hive in large quantities, it cannot be processed immediately, but is stored as hanging droplets or as partly filled cells over a wide area of the combs. These small quantities of fluid lose moisture rapidly and are then processed and consolidated into full cells of honey. The filled cells are sealed with a capping of new wax.
Processing changes the raw material containing 25 to 40 percent solids, mostly sugars, into honey containing an average of about 83 percent solids. This rise in the percentage of soluble solids is proportional to the drop in moisture content. In addition to these changes in physical properties, extensive changes in chemical composition take place during processing. Nectar usually contains a mixture of two or three sugars: sucrose (common table sugar), dextrose (glucose), and levulose (fructose). During nectar processing, enzymes present in the fluid split most of the sucrose into the two simpler sugars, dextrose and levulose. At the same time, enzymes are also responsible for synthesizing other, more complex sugars and transforming some of the dextrose into gluconic acid, the primary acid in honey.
The final composition of different honeys is variable and complex, and differs according to the plant source. Sugars make up 95 percent or more of the solids present. The simple sugars (levulose and dextrose) account for nearly 70 percent, and levulose is usually predominant. As many as 12 complex sugars including maltose are present in small quantities. Although sucrose is often found in high concentration in nectar, as in nectar from the clovers, it makes up only 1 to 2 percent of honey on the average. Enzymes present in honey include invertase, diastase, catalase, and glucose oxidase. There are many acids in honey besides gluconic acid, and together they contribute to its noticeably acid reaction (pH about 4). Hydrogen peroxide in honey is a factor in the antibiotic properties of honey. This material and the high density and acidity of honey make it toxic to many disease organisms. Because most honeys are supersaturated solutions of dextrose, they are unstable as a liquid. The excess dextrose eventually crystallizes out of the solution in the process called granulation. Some honeys never granulate, while others granulate in the comb before they can be extracted.
Honey bees produce only comb honey, and the final product is sealed beneath a solid layer of wax cappings. However, man has never been satisfied to have only the single product, so there are different forms of honey whose names relate to the different methods of production and preparation for market. These forms include section comb honey, bulk comb honey, cut comb honey, chunk honey, liquid honey, and granulated honey.
Section comb honey is produced in small, square or rectangular wooden frames called sections. Each one holds about a pound of comb honey. Bulk comb honey is produced in shallow extracting frames, which can be sold as a unit containing several pounds of honey. Such comb can be cut into pieces called cut comb honey and sold in bags or plastic boxes. If the pieces are packed into jars and surrounded by liquid honey, they are called chunk honey. Liquid honey, also called extracted or strained honey, is separated from the comb by any of several methods. When honey solidifies it is known as granulated, crystallized, creamed, or candied honey. The granulation may be natural or the result of a special process.