More about Honey Bees
Reproduction and Development
The queen controls the sex of her offspring. When an egg passes from her ovary to her oviduct, the queen determines whether the egg is fertilized with sperm from the spermatheca. A fertilized egg develops into a female honey bee, either worker or queen, and an unfertilized egg becomes a male honey bee, or drone. The queen lays the eggs that will develop into more queens in specially constructed downward-pointing, peanut-shaped cells, in which the egg adheres to the ceiling. These cells are filled with royal jelly to keep the larvae from falling and to feed them.
Worker bees are raised in the multi-purpose, horizontally arranged cells of the comb. Future workers receive royal jelly only during the first two days, compared to future queens, who are fed royal jelly throughout their larval life. This difference accounts for the great variation in anatomy and function between adult workers and queens. On average, the development of the queen from egg to adult requires 16 days; that of the worker, 21 days; and that of the drone, 24 days.
Field honey bees collect flower nectar. On entering the hive with a full honey sac, which is an enlargement of the esophagus, the field bee regurgitates the contents into the mouth of a young worker, called the house, or nurse, bee. The house bee deposits the nectar in a cell and carries out the tasks necessary to convert the nectar to honey. When the honey is fully ripened, the cell is sealed with an airtight wax capping. Both old and young workers are required to store the winter supplies of honey.
Pollen is carried into the nest or hive on the hind legs of the field bees and placed directly in the cells. The pollen of a given load is derived mostly from plants of one species, which accounts for the honey bee's outstanding role as pollinator. If it flew from one flower species to another, it would not be effective in the transfer of pollen, but by confining its visits on a given trip to the blossoms of a single species, it provides the cross-pollination required in many varieties of plants.
An amazing symbolic communication system exists among honey bees. In studies of bees begun in the early 1900s, the Austrian zoologist Karl von Frisch determined many of the details of their means of communication. In a classic paper published in 1923, von Frisch described how after a field bee discovers a new source of food, such as a field in bloom, she fills her honey sac with nectar, returns to the nest or hive, and performs a vigorous but highly standardized dance. If the new source of food is within about 90 m (about 295 ft) of the nest or hive, the bee performs a circular dance, first moving about 2 cm (about .75 in) or more, and then circling in the opposite direction.
Numerous bees in the nest or hive closely follow the dancer, imitating her movements. During this ceremony, the other workers scent the fragrance of the flowers from which the dancer collected the nectar. Having learned that food is not far from the nest or hive, and what it smells like, the other bees leave the nest or hive and fly in widening circles until they find the source.
If the new source of nectar or pollen is farther away, the discoverer performs a more elaborate dance characterized by intermittent movement across the diameter of the circle and constant, vigorous wagging of her abdomen. Every movement of this dance seems to have significance. The number of times the bee circles during a given interval informs the other bees how far to fly for the food. Movement across the diameter in a straight run indicates the direction of the food source. If the straight run is upward, the source is directly toward the sun. Should the straight run be downward, it signifies that the bees may reach the food by flying with their backs to the sun. In the event the straight run veers off at an angle to the vertical, the bees must follow a course to the right or left of the sun at the same angle that the straight run deviates from the vertical.
Bees under observation in a glass hive demonstrate their instructions so clearly that it is possible for trained observers to understand the directions given by the dancers. Certain aspects of the dance language, such as how attendant bees perceive the motion of dancers in the total darkness of the nest or hive, are still unknown. The dance language is an important survival strategy that has helped the honey bee in its success as a species.
Problems of Survival
Honey bees are subject to various diseases and parasites. American and European foulbrood are two widespread contagious bacterial diseases that attack bee larvae. A protozoan parasite, Nosema, and a virus cause dysentery and paralysis in adult bees. Two species of blood-sucking parasitic mites are particularly troublesome for beekeepers and are currently affecting wild honey bees worldwide.
The honey bee tracheal mite lives in the breathing tubes of adult bees; the varroa mite lives on the outside of larvae and adults. These mites have killed tens of thousands of honey bee colonies in North America during the past ten years. Scientific breeding programs are attempting to develop tolerant strains of domestic honey bees to replace the mite-susceptible ones currently used. Tracheal mite infestations can be reduced by fumigation of the hive with menthol fumes. Varroa mites are controlled with a miticide or, in some European countries, with fumes of formic acid. Certain hive management techniques also can reduce infestations.
Many other animals prey upon individual honey bees, which may sometimes weaken colonies. Examples are cane toads and bee eaters (birds), which pick off foragers near the colony entrance; robber flies, which take individual foragers as they visit flowers; and hornets and bee wolves (wasps), which may enter the nest or hive and steal larvae. Bears have an insatiable appetite for honey and bee larvae and may destroy many nests or hives in a single raid.
Honey bee colonies used in commercial pollination and those kept in urban areas are exposed to pesticides, fungicides, fertilizers, and other agricultural chemicals and are frequently poisoned by accident. This is a major concern of modern beekeepers.
Honey bees have become the primary source of pollination for approximately one-fourth of all crops produced in the United States and some other countries. The value of the crops that rely on such pollination has been estimated as high as billion annually in the United States. Examples of fruit crops that rely on honey bees are almonds, apples, apricots, avocados, blackberries, blueberries, cantaloupes, cherries, cranberries, cucumbers, pears, raspberries, strawberries and watermelons. The seeds of many vegetables are also produced with honey bee pollination; examples include alfalfa, asparagus, broccoli, brussel sprouts, cabbage, carrots, clover, cotton, cucumbers, onions, radishes, squash, sweet clover, and turnips.
Many species of wild pollinators have disappeared from the land as their habitats have been destroyed or altered by humans. The honey bee has taken over as pollinator of many of the wild plants that remain; its ecological value in this regard is tremendous.
Honey bees are the sole source of honey and beeswax, a fine wax with unusual qualities. Honey bees also produce propolis, a gummy substance made from tree sap that has antibacterial properties, and royal jelly and pollen for human consumption. Honey bee venom is extracted for the production of antivenom therapy and is being investigated as a treatment for several serious diseases of the muscles, connective tissue, and immune system, including multiple sclerosis and arthritis.
Honey bees comprise the genus Apis in the family Apidae, order Hymenoptera. The European honey bee is classified as Apis mellifera, the Indian honey bee is A. cerana, Koschevnikov's honey bee is A. koschevnikovi, the dwarf honey bee is A. florea, the andreniform dwarf honey bee is A. andreniformis, the giant honey bee is A. dorsata, and the mountain giant honey bee is A. laboriosa. The Italian race of the European honey bee is A. m. ligustica, the Carniolan race is A. m. carnica, and the Caucasian race is A. m. causcasia.