Queen
Drones
Workers
Brood
Bee Development

Figure 1. Three types of honey bees normally found in a honey bee colony: worker, queen, and drone. (Courtesy of the U.S. Department of Agriculture.)

Honey bees are social insects. A honey bee colony typically consists of several thousand bees that cooperate in nest building, food collection, and brood rearing. Fach member has a definite task to perform, but it takes the combined efforts of the entire colony to survive and reproduce. A colony normally has a single queen, fifty to sixty thousand workers at its peak, and several hundred drones during late spring and summer. (See figure 1.) Individual queens, workers, and drones cannot survive by themselves. The social structure of the colony is maintained by the queen and workers and depends on an effective system of communication. The exchange of chemical secretions among members and communicative "dances" are undoubtedly responsible for controlling the activities necessary for colony survival. Division of labor within the worker caste primarily depends on the age of the bee but varies with the needs of the colony. Reproduction and colony strength depend on the queen, the quantity of food stores, and the size of the worker force. As the size of the colony increases up to about sixty thousand workers, so does the efficiency of the colony.

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Queen
There is only one queen per colony, except during swarming preparations or supersedure. Since she is the only sexually developed female, her primary function is reproduction. She produces both fertilized and unfertilized eggs. Queens lay the greatest number of eggs in the spring and early summer. During peak production, they may lay up to fifteen hundred eggs per day. They gradually cease to lay eggs in early October and do not begin again until January. One queen may produce up to two hundred fifty thousand eggs per year and possibly more than a million in her lifetime. The queen is the only colony member that can live for several years, sometimes for as long as five to seven years. However, since the queen's average productive life span is two to three years, most beekeepers find it profitable to requeen their colonies every year or two.

A queen is easily distinguished from other members of the colony. Her body is normally much longer than either the drone's or worker's, especially during the egg-laying period when her abdomen is greatly elongated. Her wings cover only about two-thirds of the abdomen, whereas the wings of both workers and drones nearly reach the tip of the abdomen when folded. A queen's thorax is slightly larger than that of a worker, and she has neither polien baskets nor functional wax glands. Her stinger is curved and longer than that of the worker, but it has fewer and shorter barbs.

The qualities of the colony depend on the egg laying and chernical production of the queen. Her genetic makeup, along with that of the drones she has mated with, determine the quality, size, and temperament of the colony.

About one week after emerging from a queen cell, the queen is ready to leave the hive and mate with several drones in flight. Since she will be flying some distance from her colony to avoid inbreeding, she first circles the hive to orient herself to its location. She leaves the hive by herself and is gone approximately thirteen rninutes. The queen mates, usually in the afternoon, with seven to fifteen drones. Drones are attracted to her only at an altitude above 20 feet. After mating she returns to the hive and will begin laying in about forty-eight hours. She releases several sperm from the spermatheca each time she lays an egg destined to become either a worker or queen. If bad weather delays the queen's mating flight for more than twenty days, she may lose the urge to mate and will become a drone layer.

The queen is constantly attended and fed royal jelly by the colony's worker bees. The number of eggs the queen lays depends on the amount of food she receives and the size of the worker force capable of caring for the brood. When the sperm supply begins to be depleted, the workers prepare to replace or supersede her. The old queen and her new daughter may both be present in the hive for some time following supersedure.

Queens develop from fertilized eggs or from young worker larvae not more than three days old. New queens are raised if any of three different impulses occur in the hive: emergency, supersedure, or swarming. When an old queen is accidently killed, lost, or removed, the bees select older worker larvae to produce emergency queens. These queens are raised in modified worker cells on the comb surface. When an older queen begins to fail (reduced egg laying or decreased production of queen substance), the colony prepares to raise a new queen. Queens produced under the supersedure impulse are usually better than emergency queens, since they receive larger quantities of food (royal jelly) during development. Like emergency queen cells, supersedure queen cells typically are raised on the comb surface. (See figure 2.) In comparison, queen cells produced in preparation for swarming are found along the bottom of the frames.

Figure 2. Emergency or supersedure queen cells and a queen cup built on the Queen surface.

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Drones
Drones (male bees) are the largest bees in the colony. They are generally present only during late spring and summer. The drone's head is much larger than that of either the queen or worker, and its compound eyes meet at the top of its head. Drones have no stinger, pollen baskets, or wax glands. Their main function is to fertilize the virgin queen during her mating flight. Only a small percentage of drones fulful this function. Drones become sexually mature about twelve days after emerging and die instantly upon mating. They perform no useful work for the hive. However, the presence of a few drones is believed to improve the general morale of the colony during the honey flow.

While drones normally rely on workers for food, they can feed themselves within the hive after they are four days old. Since drones eat three times as much food as workers, an excessive number of drones certainly places an added stress on the colony's food supply. Drones stay in the hive until about eight days old, then begin to take orientation flights. Flight from the hive normally occurs between noon and 4:00 p.m. Drones have never been observed taking food from flowers.

When cold weather begins in the fall and the honey flow stops, drones usually are forced out into the cold and left to starve. Queenless colonies, however, allow them to stay in the hive indefinitely.

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Workers
Workers are the smallest and most numerous bees in the colony. They are sexually undeveloped females and under normal hive conditions do not lay eggs. Workers have specialized structures, such as brood food glands, scent glands, wax glands, and pollen baskets, which allow them to perform all the labors of the hive. They clean out the cells, feed the brood, care for the queen, remove debris, handle incorning nectar, build combs, guard the entrance, and air condition and ventilate the hive before going into the field. In the field, they forage for nectar, pollen, water, and propolis (plant sap).

The life span of the worker durmg summer is about six weeks. Those reared in the fall may live as long as six months, allowing new generations to develop early in the spring before they die.

Laying Workers. The presence of laying workers in a colony usually means the colony has been queenless for approximately two weeks. However, laying workers also may be found in normal "queenright" colonies during the swarming season and when the colony is headed by a poor queen. When a colony becomes hopelessly queenless, the ovaries of several workers develop and workers begin to lay unfertilized eggs. Development of the workers' ovaries is believed to be inhibited by the presence of brood, the queen, and her chemicals. Colonies with laying workers are recognized easily: only drones are reared in worker-sized cells; there may be anywhere from five to fifteen eggs per cell; and the eggs of a laying worker are smaller than those of the queen. In addition, laying workers scatter their eggs more randomly over the brood combs, and eggs are usually on the sides of the cell instead of at the base, where they are placed by a queen. Some of these eggs do not hatch, and many of the drone larvae that do hatch do not survive to maturity in the smaller cells. Drones that do mature are normally undersized. The activities of a laying worker are sirnilar to those of normal workers. They consume pollen and honey as well as forage in the field.

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Brood
Eggs. Honey bee eggs are normally laid, one to a cell, by the queen. Each egg is attached to the cell bottom and looks like a tiny grainof rice. When first laid, the egg stands straight up, on end. However, during the three day development period the egg begins to bend over. On the third day the egg hatches into a tiny grub and the larvalstage begins.

Larvae. Healthy larvae are pearly white in color with a glistening appearance. They are curled in a "C" shape on the bottom of the cell. Worker, queen and drone cells are capped after larva are approximately 5.5, 6, and 6.5 days old, respectively. The period just after the cell is capped is called the prepupal stage. During this stage the larva is still grub-like in appearance but stretches itself out lengthwise in the cell and spins its cocoon. Larvae remain pearly white, plump and glisten during the prepupal stage.

Pupae
After two days, prepupae begin to change from their larval form to adult bees. Healthy pupae remain white and glisten during the initial stages of development, even though their bodies begin to transform into adult forms. Compound eyes are the first areas that begin to take on color; changing from white to brownish-purple. Soon after this, the rest of the body begins to take on the color of an adult bee. New workers queens, and drones emerge approximately 12, 7.5 and 14.5 days, respectively, after their cells are capped.

Brood patterns
Healthy brood patterns are easily recognized when looking at capped brood. Frames of healthy capped worker brood normally have a solid pattern. Cappings are medium brown in color, convex and without puncture cappings.

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Bee Development
All three types of honey bees pass through three developmental stages before emerging as adults: egg, larva, and pupa. While the developmental stages are similar, they do differ in duration. (See Table 1.) Unfertilized eggs become drones, while fertilized eggs become either workers or queens. (See figure 3.) Nutrition plays an important part in caste development of female bees.

Table 1. Developmental stages of the three castes of bees.

Developmental Duration of stage
stage	Queen	Worker	Drone
Days
Egg	3	3	3
Larval stage	5-1/2	6	6-1/2
Pupal stage	7-1/2	12	14-1/2
Total developmental time	16	21	24

Figure 3. Comb of sealed worker brood with drone cells in the lower left corner and a sealed queen cell in the the lower right corner. (Courtesy of the University of California)