Western honey bee (Apis mellifera)

Distribution▲ Back to top

The western honey bee is native to the continents of Europe, Asia, and Africa. As of the early 1600s, the insect was introduced to North America, with subsequent introductions of other European subspecies two centuries later. Since then, they have spread throughout the Americas.

Western honey bees differentiated into geographic races as they spread from Africa into Eurasia. Currently, 28 subspecies based on these geographic variations are recognized. All races are cross-fertile, though reproductive adaptations may make crossing unlikely. The 28 subspecies can be assigned to one of four major branches based on work by Ruttner, and subsequently confirmed by analysis of mitochondrial DNA. African subspecies are assigned to branch A, northwest European subspecies to branch M, southwest European subspecies to branch C, and Mideast subspecies to branch O. The subspecies are grouped and listed in the sidebar. Regions with localized variations may become identified subspecies in the near future, such as ''A. m. pomonella'' from the Tian Shan Mountains, which would be included in the Mideast subspecies branch.

Geographic isolation led to numerous adaptations as honey bees spread after the last ice age. These adaptations include brood cycles synchronized with the bloom period of local flora, forming a winter cluster in colder climates, migratory swarming in Africa, enhanced foraging behavior in desert areas, and numerous other inherited traits.

Behavior▲ Back to top

In the temperate zone, honey bees survive winter as a colony, and the queen begins egg laying in mid to late winter, to prepare for spring. This is most likely triggered by longer day length. She is the only fertile female, and deposits all the eggs from which the other bees are produced. Except for a brief mating period when she may make several flights to mate with drones, or if she leaves in later life with a swarm to establish a new colony, the queen rarely leaves the hive after the larvae have become full-grown bees. The queen deposits each egg in a cell prepared by the worker bees. The egg hatches into a small larva which is fed by 'nurse' bees . After about a week, the larva is sealed up in its cell by the nurse bees and begins the pupal stage. After another week, it will emerge an adult bee.

For the first 10 days of their lives, the female worker bees clean the hive and feed the larvae. After this, they begin building comb cells. On days 16 through 20, a worker receives nectar and pollen from older workers and stores it. After the 20th day, a worker leaves the hive and spends the remainder of its life as a forager. The population of a healthy hive in mid-summer can average between 40,000 and 80,000 bees.

The larvae and pupae in a frame of honeycomb are referred to as frames of brood and are often sold by beekeepers to other beekeepers to start new beehives.

Both workers and queens are fed "royal jelly" during the first three days of the larval stage. Then workers are switched to a diet of pollen and nectar or diluted honey, while those intended for queens will continue to receive royal jelly. This causes the larva to develop to the pupa stage more quickly, while being also larger and fully developed sexually. Queen breeders consider good nutrition during the larval stage to be of critical importance to the quality of the queens raised, with good genetics and sufficient number of matings also being factors. During the larval and pupal stages, various parasites can attack the pupa/larva and destroy or damage it.

Queens are not raised in the typical horizontal brood cells of the honeycomb. The typical queen cell is specially constructed to be much larger, and has a vertical orientation. However, should the workers sense the old queen is weakening, they will produce emergency cells known as supersedure cells. These cells are made from a cell with an egg or very young larva. These cells protrude from the comb. As the queen finishes her larval feeding, and pupates, she moves into a head downward position, from which she will later chew her way out of the cell. At pupation, the workers cap or seal the cell. Just prior to emerging from their cells, young queens can often be heard "piping". The purpose of this sound is not yet fully understood.

Worker bees are infertile females, but in some circumstances, generally only in times of severe stress or with the loss or injury or declining health of the queen, they may lay infertile eggs, and in some subspecies these eggs may actually be fertile. However, since the worker bees are 'imperfect' females , they do not mate with drones. Any fertile eggs they lay would be haploid, having only the genetic contribution of their mother, and in honey bees these haploid eggs will always develop into drones. Worker bees also secrete the wax used to build the hive, clean and maintain the hive, raise the young, guard the hive and forage for nectar and pollen.

In honey bees, the worker bees have a modified ovipositor called a stinger with which they can sting to defend the hive, but unlike other bees of any other genus , the stinger is barbed. Contrary to popular belief, the bee will not always die soon after stinging: this misconception is based on the fact that a bee will usually die after stinging a human or other mammal. The sting and associated venom sac are modified so as to pull free of the body once lodged , and the sting apparatus has its own musculature and ganglion which allow it to keep delivering venom once detached. This complex apparatus, including the barbs on the sting, is presumed to have evolved specifically in response to predation by vertebrates, as the barbs do not function unless the sting is embedded in elastic material. Even then, the barbs do not always "catch", so a bee may occasionally pull the sting free and either fly off unharmed, or sting again.Honey bees are an excellent animal species to study with regard to behavior because they are abundant and familiar to most people. An animal that is disregarded every day has very specific behaviors that go unnoticed by the normal person. Karl von Frisch, who was awarded the Nobel Prize for physiology and medicine in 1973 for his study of honey bee communication, noticed bees communicate through the language of dance. Honey bees are able to direct other bees to food sources through the round dance and the waggle dance. The round dance tells the other foragers that food is within 50 meters of the hive, but it does not provide much information regarding direction. The waggle dance, which may be vertical or horizontal, provides more detail about both the distance and the direction of the located food source. Bees also are thought to rely on their olfactory sense to help locate the food source once the foragers are given directions from the dances.

Another signal for communication is the shaking signal, also known as the jerking dance, vibration dance, or vibration signal. It is a modulatory communication signal because it appears to manipulate the overall arousal or activity of behaviors. The shaking signal is most common in worker communication, but it is also evident in reproductive swarming. A worker bee vibrates its body dorsoventrally while holding another honey bee with its front legs. Jacobus Biesmeijer examined the incidence of shaking signals in a forager's life and the conditions that led to its performance to investigate why the shaking signal is used in communication for food sources. Biesmeijer found that the experienced foragers executed 92.1% of the observed shaking signals. He also observed that 64% of the shaking signals were executed by experienced foragers after they had discovered a food source. About 71% of the shaking signal sessions occurred after the first five foraging success within one day. Then other communication signals, such as the waggle dance, were performed more often after the first five successes. Biesmeijer proved that most shakers are foragers and that the shaking signal is most often executed by foraging bees over pre-foraging bees. Beismeijer concluded that the shaking signal presents the overall message of transfer work for various activities or activity levels. Sometimes the signal serves to increase activity, when bees shake inactive bees. At other times, the signal serves as an inhibitory mechanism such as the shaking signal at the end of the day. However, the shaking signal is preferentially directed towards inactive bees. All three types of communication between honey bees are effective in their jobs with regards to foraging and task managing.

⟶ "The general story of the communication of the distance, the situation, and the direction of a food source by the dances of the returning worker bee on the vertical comb of the hive, has been known in general outline from the work of Karl von Frisch in the middle 1950s."

Habitat▲ Back to top

In North America, Africanized bees have spread across the southern United States where they pose a small danger to humans, although they may make beekeeping difficult and potentially dangerous .

As an invasive species, feral honey bees have become a significant environmental problem in places where they are not native. Imported bees may compete with and displace native bees and birds, and may also promote the reproduction of invasive plants that native pollinators do not visit. Also, unlike native bees, they do not properly extract or transfer pollen from plants with poricidal anthers , as this requires buzz pollination, a behavior which honey bees rarely exhibit. For example, honey bees reduce fruiting in ''Melastoma affine'' by robbing stigmas of previously deposited pollen.

Reproduction▲ Back to top

Numerous traits are present in the various subspecies of honeybees that are amenable to selection via breeding. This listing covers a small part of the variation present in the honeybee genome.

1. Egg Laying Rate – Queen can lay a few hundred eggs per day up to about 5,000 eggs per day.

2. Egg Viability Rate – Can range from 0 up to 100% of eggs that hatch and develop into bees.

3. Brood Cycle Length – For worker bees ranges from 17 days up to 21 days.

4. Brood Nurturing – This is a measure of how intent the nurse bees are at nurturing brood.

5. Foraging Aggressiveness – This trait determines potential for honey production.

6. Time Of Foraging – Some bees forage earlier in the day and later in the evening than others.

7. Disease Resistance – This is a measure of innate tolerance to brood diseases and adult diseases.

8. Pest Resistance – This is a measure of innate tolerance to pests such as tracheal and varroa mites.

9. Defensive Behavior – Determines aggressiveness and stinging propensity.

10. Swarming Tendency – This determines the timing and success of colony reproduction.

11. Winter Hardiness – Clustering behavior and ability to survive extended low temperatures.

12. Life Span – Ranges from a 22 days up to 305 days for workers with an average of 36 days.

13. Body Size – Small bees are typical in Africa with larger bees typical in colder climates.

14. Sense Of Smell – Ability to detect flower odors and respond to nectar availability.

15. Hygienic Cleaning Behavior – This is a major component of both disease and pest resistance.

16. Time Of Brood Development – Bees must begin brood rearing at least 8 weeks before nectar flows.

17. Thrift – Adjustment of brood production to available food sources for efficient use of resources.

18. Honey Arrangement – Storing honey closer to or further away from the brood next.

19. Pollen Collection – Amount and floral source of pollen are under direct genetic control.

20. Type Of nectar Collected – This has a major impact on honey quality and value.

21. Comb Building – Willingness to build comb and expand the colony.

22. Capping Structure – Ranges from flat and watery to gray to white dome shaped cappings.

23. Propolis Collection – Associated with wintering success, ranges from none to covering all hive surfaces.

24. Brace Comb Construction – Ranges from very little to cross comb throughout the colony.

25. Abdominal Color – Ranges from black to various color stripes in tan, yellow, and orange.

26. Antennae Structure – Number and placement of sensors is inherited, associated with sense of smell.

27. Number of Drones Produced – Ranges from very few up to ¼ of brood combs.

28. Number of Queens Produced – Ranges from a few up to several hundred.