BY STEPHEN TABER III(1)

BEEKEEPING IN THE UNITED STATES
AGRICULTURE HANDBOOK NUMBER 335
Revised October 1980


Bee behavior refers to what bees do - as individuals and as a colony. By studying their behavior, we may learn how to change it to our benefit.

Two practical discoveries of bee behavior made our beekeeping of today possible. One was the discovery by Langstroth of bee space. The other was the discovery by G. M. Doolittle that large numbers of queens could be reared by transferring larvae to artificial queen cups. The discovery of the "language" of bees and of their use of polarized light for navigation has attracted considerable interest all over the world.

Much has been learned about the behavior of insects, including bees, in recent years. As an example, the term "pheromone" had not been coined in 1953, when Ribbands summarized the subject of bee behavior in his book, The Behaviour and Social Life of Honeybees. A pheromone is a substance secreted by an animal that causes a specific reaction by another individual of the same species. Now many bee behavior activities can be explained as the effect of various pheromones.

Recently, we have learned how certain bee behavior activities are inherited, and this information gives us a vast new tool to tailor-make the honey bee of our choice. Further studies should reveal other ways to change bees to produce specific strains for specific uses.

(1) Apiculturist, Science and Education Administration, Carl Hayden Center for Bee Research, Tuscon, Ariz. 85719.

The Honey Bee Colony

The physical makeup of a colony has been described. An additional requirement of a colony is a social pattern or organization, probably associated with a "social pheromone." It causes the bees to collect and store food for later use by other individuals. It causes them to maintain temperature control for community survival when individually all would perish. Individuals within the colony communicate with each other but not with bees of another colony. Certain bees in the colony will sting to repel an intruder, even though the act causes their death. All of these, and perhaps many other organizational activities, probably are caused by pheromones.

There is no known governmental hierarchy giving orders for work to be done, but a definite effect on the colony is observed when the queen disappears. This effect seems to be associated with a complex material produced by the queen that we refer to as "queen substance." There also is evidence that the worker bees from 10 to 15 days old, who have largely completed their nursing and household duties but have not begun to forage, control the "governmental" structure. Just what controls them has not been determined.

These and many other factors make an organized colony out of the many thousands of individuals.

The Domicile

When the swarm emerges from its domicile and settles in a cluster on a tree, certain "scout bees" communicate to it the availability of other domiciles. At least some of these domiciles may have been located by the scout bees before the swarm emerged. The various scouts perform their dances on the cluster to indicate the direction, distance, and desirability of the domiciles. Eventually, the cluster becomes united in its approval of a particular site. Then the swarm moves in a swirling mass of flying bees to it. Agreement always is unanimous.

When a swarm or combless package is placed in a box, allowed to fly, and supplied with abundant food, it builds comb. With a laying queen present, the first comb is "worker" in design, with about 25 cells per square inch. As the population of bees grows larger, and after there is a considerable amount of worker comb built, comb containing larger cells is constructed. This comb, termed storage comb by Langstroth, is used for rearing drones. We have found that bees store their first honey all across the top of the combs, utilizing both drone and worker cells.

The space between honey storage combs is much more uniform than between brood combs. The space left between capped honey cells is usually one-fourth inch or even less - room enough for one layer of bees to move.

As the colony ages, the combs that were first used for rearing worker bees may be converted to honey storage comb; areas damaged in any way are rebuilt. These changes usually affect the bee space and result in combs being joined together with "brace" comb. Strains of bees show genetic variation in building these brace combs.

All these cells are horizontal or nearly so; vertical cells are used for rearing queens. Why horizontal cells are used for the rearing of brood and for honey and pollen storage, whereas vertical cells are built only for queen production, is unknown.

Flight Behavior

When several thousand bees and a queen are placed in new surroundings - which happens when the swarm enters its new domicile or a package of bees is installed, or a colony is moved to a new location - normal flight of some workers from the entrance may occur within minutes. If flowering plants are available, bees may be returning to the hive with pollen within an hour. Bees transferred by air from Hawaii to Louisiana and released at 11:30 a.m. were returning to the new location with pollen loads within an hour. Package bee buyers in the Northern States have noticed similar patterns in bees shipped from the South.

What causes this virtually instant foraging by bees? What determines whether they collect pollen, nectar, or water? If food and water in the hive are sufficient, why should they leave to forage? Answers to these questions may lead to our directing bees to specific duties we desire accomplished.

Housecleaning

Certain waste material accumulates in a normal colony. Adult bees and immature forms may die. Wax scales, cappings from the cells of emerging bees, particles of pollen, and crystallized bits of honey drop to the floor of the hive. Intruders, such as wax moths, bees from other colonies, and predators, are killed and fall to the floor. Worker bees remove this debris from the hive.

The cleaning behavior of some strains of bees, associated with removal of larvae and pupae that have died of American foulbrood, is genetically controlled by two genes. This discovery is important not only because it might help in developing bees resistant to diseases, but also in indicating that other behavior characteristics of bees can be genetically modified to suit special needs.

Known Pheromone Activity

Chemicals that bees and other insects produce that influence, or direct, behavior of other bees are broadly called pheromones. In honey bees these chemicals are produced by the queen, workers, and probably drones. A list of the known chemicals associated with the queen and worker is given in tables 1 and 2.

This is an interesting and new area for bee research, as this list represents just a beginning. Research has indicated the existence of many other pheromones, which are as yet undocumented. If interested in this topic, consult the technical work listed in Gary (1974).

TABLE 1. - Queen pheromones
Gland or source and chemical	Behavior reactions in colonies	Citations(1)
Mandibular:
9-oxodecenoic acid 10-hydroxydecenoic deconic acid	Recognition of queen and reduction of egg laying by workers.	{Butler (1964).
9-oxodec-trans-2-enoic acid	Mating attractant	Gary (1962).
Do	In combination with worker bees, scent gland holds swarming bees together.	Morse (1971).
(1) Citations are not listed; consult Gary (1974).

TABLE 2. - Worker bee pheromones
Producing gland or source	Chemical compound	Behavior reactions in colony	Citations(1)
Nassanoff or scent	Geraniol	Fanning attractant	Bock (1963).
Do	Nerolic acid Geranic acid	do do	{Boch (1964).
Do	Citral	do	Shearer (1966).
Do	All compounds of scent gland.	Swarm attraction and stabilization.	Morse (1971).
Sting	Iso-pentyl acetate	Colony alarm	Bock (1962).
Mandibular	2-heptanone	Alarm communications	Bock (1965).
(1) Citations are not listed; consult Gary (1974).

Pheromonal bee behavior activity patterns are easily observable. Nassanoff or scent gland activity is best seen when a swarm is hived. When the bees first enter the new domicile, some bees stand near the entrance and fan. At the same time, they turn the abdominal tip downward to expose a small, wet, white material on top of the end of the abdomen. This seems to affect the other bees, for within several minutes all will have entered the new hive. When bees find a new source of food, they also mark it with the same chemical.

Colony odor refers to the odor of one colony. Because each colony odor is different, colonies cannot be combined into one hive without the bees fighting and killing one another. This odor probably results from a combination of endogenous (pheromone or pheromonelike) materials and exogenous (food) materials in each hive and seems to be recognizably different for every colony.

When colonies are to be combined, the beekeeper usually places a newspaper between the two sets of bees. By the time the bees have eaten through and disposed of the newspaper, their odors have intermingled and become indistinguishable. During heavy honey flows, differences between colonies seem to disappear, or be submerged by the scent of nectar, and colonies can be united without difficulty.

One of the most interesting and complex pheromones, originally termed "queen substance," is now believed to be a complex of different chemical pheromone compounds which stimulate a large number of complex behavior responses. Its presence in virgin queens in flight attracts the drone for mating from an unknown distance. Its presence in virgin and mated queens prevents the ovaries of the worker bee within the hive from developing and the worker bees from building queen cells. It keeps swarming bees near the queen. Its decrease is a cause of swarm preparation or supersedure. Queen substance is produced in glands in the queen's head. The alarm or sting pheromone also may be a complex of pheromones. When a bee stings, other bees in the immediate vicinity also try to sting in the same place. Smoke blown onto the area seems to neutralize this effect.

Cause of Stinging Bees or Temper

The term "temper" of bees refers to their inclination to sting. Many factors influence the temper of bees, and it is a difficult subject to study. Environment of the hive and manipulation by an individual beekeeper certainly influence temper responses of bees. Temper is probably influenced tremendously by the genetics or inheritance of the bee as well as the environment. The Brazilian or Africanized bee is thought to be more genetically prone to sting than bees in the United States.

Temper of bees commonly has been controlled with smoke. Just why and how smoke affects bees is unknown, even though it has been used by beekeepers worldwide for hundreds of years. Furthermore, instructing beginners and novices exactly when and how to use smoke on bees is almost impossible. It is something that is learned from experience.

The following brief instruction might help beekeepers with limited experience: Smoke the entrance gently enough to force guard bees inside, raise cover, smoke gently. Smoke bees only when they fly up from combs toward hands and face. Move slowly and deliberately. Break propolis seals between hive bodies and frames slowly and evenly.

Don't jar or bump combs and bees. During cold weather, propolis joints snap when pried apart un-ess care is taken. If combs are kept clean of propolis and burr and brace comb and if care is taken not to crush bees when moving combs and supers, they can be kept quite gentle.

Great care should be exercised in the placement of colonies of bees so that they cannot become a nuisance to friends and neighbors. Bees visiting nearby fishponds, swimming pools, and stock-watering troughs can be a real nuisance as well as dangerous to people and animals. Springtime flight of bees voiding feces and spotting laundry hanging on a line or a new car is irritating. Good public relations are important for beekeepers. Talk to your neighbors about the importance of bees in the community and country at large. Help them to understand that your bees and others are responsible for important pollination and share some honey with them occasionally.

Colony Morale

"Colony morale" generally refers to the well-being of the colony. If the morale is good, the bees are doing what is desired of them, including increasing the colony population, making honey, and pollinating flowers. Many factors affect colony morale. For example, if the queen is removed from a colony during a honey flow, the daily weight gains immediately decrease, although the bee population for the next 3 weeks is unaltered. Also, when a colony is preparing to swarm, the bees practically stop gathering pollen and nectar. Improper manipulations or external environment also affects colony morale. A colony has good morale when the maximum number of bees are making the maximum number of flights to gather nectar and pollen.

Other Methods of Bee Communication

There are other methods of bee communication besides the one involving chemical pheromones. The best known is the "dance" of the returned forager bee so well elucidated by von Frisch and his many students, particularly M. Lindaner.

This dance is so precise that it tells other bees not only in which direction to go but also how far to fly in search of food. This was the first non-human language to be interpreted. The experiments on bee communication by dances were done with dishes of sugar water and not under true foraging conditions of bees collecting nectar from plants. When a returning forager comes back to the hive after finding a highly attractive 100-acre field of sweetclover, does she direct bees to the spot she was working or to the whole field? The last word in dance communication of bees certainly has not yet been written.

Even the most uninitiated are familiar with the soft quiet hum of bees collecting nectar and pollen on their foraging trips. In the hive itself, there are many more bee noises or sounds which are much more subtle. Experienced beekeepers recognize a difference in sound between a colony with a queen and one without. Individual queens and even worker bees emit squeaky sounds called "piping" and "quacking." The bee literature is full of many explanations of the causes and meanings of these sounds. Since these sounds and other hive sounds are now under careful scientific scrutiny, it is really premature to say definitely that they have certain defined meanings. This field of interest may produce useful information in the future.

According to von Frisch, when a bee returns from a foraging trip and dances, she also communicates the kind of "plant" or "flower" on which she was foraging by releasing the perfume of the flower through nectar regurgitation or from nectar aroma on body hairs. Again, most of these experiments were done with dishes of sugar water impregnated with essential oils or plant extracts. These experiments have prompted other experiments that were designed to train bees to work desired crops for pollination. These experiments were unsuccessful. The reason for the failures may well be that the bee language code has not been completely translated. We are still unable to "talk" effectively to the bees and "tell" them what we want done.

Von Frisch also discovered that bees recognize and are guided to flowers by different colors but are unable to communicate these colors. He also showed that the bee's eyes are receptive to polarized light and that polarization of the light from the sky aids the bee's navigation. How light of different wave lengths or intensity affects what goes on inside a hive is being studied.

Age Levels of Bees Correlated With Work Habits

The honey bee is adaptable to many environments. Honey bees that were native only to Europe, Asia, and Africa have adapted well to all but the polar regions of the world. Part of this adaptability lies in the capacity of the individual bee to "sense" what must be done, then to perform the necessary duty.

Under normal conditions, all ages of bees are in the hive and, in general, the bee's age determines its daily activity. In response to special needs of the colony, however, bees are capable of altering the division of labor according to age. Young bees feed larvae, build comb, and ripen nectar into honey in a rather definite sequence. After about 3 weeks, they become field bees. If many field bees are killed by pesticides, young bees go to the field at a younger age to get necessary chores accomplished.

The Performance of Colonies

Genetically, we found that some bees produce more honey than others, but we do not know why. The individual bee may collect more because of its own genetic inheritance. The colony may store more honey because of the queen's inherited ability to lay more eggs, resulting in a greater total population of bees in the hive, or because the bees are inherently longer lived.

We can affect the bee's environment in conjunction with its inheritance, and our aim is to have good-quality bees and maintain the best colony morale possible. A beekeeper's disturbance of the colony during the honey flow results in a marked decrease in the amount of honey stored for that day and even the following day. Colonies of bees should not be needlessly disturbed; however, some manipulation associated with many aspects of management is necessary.

Bee behavior toward different plants varies greatly. Some plants are particularly attractive for nectar or pollen; others are not. Strains of bees can be genetically selected to visit certain plants, and plants can be selected to be more attractive to bees. Attractive nectar or pollen, or both, can be important in ensuring pollination of bee-pollinated crops. Nectar and pollen availability in plants can be accidentally eliminated by breeding. When this occurs, there is a loss of a potential honey crop, but more important can be the loss of a seed or fruit crop because the plant no longer attracts pollinators. If plants such as soybeans, which cover enormous acreages, could be made more attractive to bees, honey and possibly soybean yields could be greatly increased.

A behavior characteristic of honey bees limits their effectiveness in pollinating some crops. Individual bees usually confine their foraging area in a series of trips to the field to a relatively small area such as a single fruit tree. On the other hand, the foraging area of a colony may comprise several square miles; honey bees flying 2.5 miles in all directions from a single hive have access to 12,500 acres. This characteristic and the fact that honey bees distribute themselves well over the area within flight range are important in locating and harvesting available nectar and pollen.

Control of Foraging

A major crop pollination goal is to control foraging bees and get them to more effectively visit and pollinate crops; conversely, we would like to repel them from areas where there is danger from insecticides or where they endanger people. Work with other insects - both social and nonsocial - indicates that this might be accomplished some day by chemical and physical means.

There is considerable evidence that different plant species produce varying attractant compounds associated with their nectar and pollen. Bees are highly attracted to the scent of recently extracted honeycomb and to the scent of honey being extracted or heated. Obviously, chemical scents of certain flowers and to some extent scents incorporated in the collected honey are attractive to bees or associated with available food.

Some pollens also contain chemical compounds that stimulate collection response in bees. Isolation and identification of these bee-attractive compounds and the application of the attractant to plant areas or altering attractants through plant breeding are an area of research of potential importance to crop pollination.

Research should not be confined to chemicals alone, but should be shared equally with various physical factors that can possibly attract or repel bees. In other entomological fields, research on physical methods of controlling insects is receiving intensive investigation. Different insects respond in differing ways; they are attracted to certain light wavelengths and repelled by others. Night-flying moths are repelled or go into defensive maneuvers because of bat sonar signals, whereas crickets and other members of their insect group can be collected by reproducing certain stridulations.

Other Behavior Activities of Bees

The Drones
The time of day that drones fly in search of a mate depends on many factors, such as the geographic location, day length, and temperature. Drones usually fly from the hive in large numbers between 11 a.m. and 4:30 p.m. Morning or early afternoon flights may last 2 or 3 hours. Later flights are shorter. When out of the hive, drones congregate in "mating areas," which may serve to attract virgin queens. These areas usually are less than 100 feet from the ground and seem to be associated with land terrain.

The Queen
The virgin queen becomes sexually mature about 5 days after emergence. She is relatively quiet in the morning and most active in the afternoon. She may begin her mating flights 5 or 6 days after emergence and go on a number of flights over several days. Mating with 8 to 12 drones will stock her spermatheca with 6 million to 7 million sperm. She will begin to lay eggs in 2 to 5 days and may continue for years.

A young, fully mated queen rarely lays drone eggs before she is several months old. After that time, she controls the sex of the offspring by laying either fertilized or nonfertilized eggs.

Worker bees occasionally kill their queen. More frequently, they will kill a newly introduced or virgin queen. To do this, 15 or 20 worker bees collect about her in a tight ball until she starves. Generally, it has been thought that bees "balled" strange or introduced queens because they did not have the proper "colony" odor. The reason for balling is probably more complicated than that, because bees occasionally will ball their own queen. Even if the ball is broken up, the queen seldom survives and the stimulus is powerful enough that the bees taking part in the queen balling are sometimes subsequently balled by other bees.

References

BUTLER, C. G.
1955. THE WORLD OF THE HONEY BEE. 226 p. Macmillan Co., New York.

VON FRISHH, K.
1955. THE DANCING BEES. 183 p. Harcourt, Brace & Co., New York.

GARY, N. E.
1974. PHEROMONES THAT AFFECT THE BEHAVIOR AND PHYSIOLOGY OF HONEY BEES. In Pheromones, M. C. Birch, p. 200-221, North-Holland, Amsterdam, and Elsevier, New York.

HAYDAK, M. H.
1963. ACTIVITIES OF HONEY BEES. In The Hive and the Honey Bee, 556 p. Dadant & Sons, Hamilton, Ill.

LINDAUR, M.
1961. COMMUNICATION AMONG SOCIAL BEES. 143 p. Harvard University Press, Cambridge.

RIBBANDS, C. R.
1953. THE BEHAVIOUR AND SOCIAL LIFE OF HONEY BEES. 318 p. Dover Publications, Inc., New York.