The western honeybee, Apis mellifera, is the most widespread honeybee species globally. Native to Europe, Africa, and the Middle East, it has been introduced by humans to nearly every continent, excluding Antarctica. This introduction was primarily for its agricultural benefits and honey production, leading to its presence across diverse climates and ecosystems worldwide as a domesticated and often feral insect.
Colony Social Structure
Western honeybee colonies function as highly organized societies, composed of three distinct castes, each with specialized roles.
The single queen bee serves as the reproductive center of the hive, laying between 2,000 and 3,000 eggs daily during peak seasons. Her longevity, spanning two to five years, supports continuous colony growth. The queen also produces pheromones that influence hive behavior, maintaining order and unity.
Male drones, numbering in the dozens, primarily mate with new queens from different colonies. These larger bees do not forage or maintain the hive; worker bees feed them. Drones live for about eight weeks, and those that do not mate are often expelled from the hive as colder weather approaches.
The vast majority of the colony, up to 60,000 individuals, consists of female worker bees, which are sterile. Their responsibilities shift as they age, a progression known as age polyethism. Younger workers perform tasks inside the hive, such as cleaning cells, nursing larvae, and building wax comb. As they mature, workers transition to guarding the hive entrance and foraging for nectar, pollen, water, and propolis. Worker bees live for about five to seven weeks during active seasons, while those born in autumn can survive for several months through winter.
Life Cycle and Development
Honeybees undergo complete metamorphosis, progressing through four stages: egg, larva, pupa, and adult. The queen initiates this cycle by laying a single egg into a hexagonal wax cell. Fertilized eggs develop into female bees (workers or new queens), while unfertilized eggs become male drones.
After three days, the egg hatches into a white, legless larva. Nurse bees feed these larvae. For the first few days, all larvae receive royal jelly, a protein-rich secretion. Larvae destined to become workers or drones are then switched to bee bread (pollen and honey), while queen larvae continue to be fed royal jelly exclusively. Larvae shed their skin multiple times as they grow.
Once the larval stage is complete, worker bees cap the cell, and the larva transforms into a pupa. Within this sealed cell, the pupa undergoes metamorphosis, developing into an adult bee. The development from egg to adult varies by caste: queens emerge in 15 to 16 days, workers in 21 days, and drones in 24 days.
Communication and Foraging
Honeybees employ effective communication methods to coordinate foraging, with the “waggle dance” as a primary example. This dance is performed by a forager bee returning to the hive, conveying precise information about a food source’s location. The dance involves a figure-eight pattern on the honeycomb.
The central straight run of the figure-eight, known as the waggle run, communicates both direction and distance. Its angle relative to the comb’s vertical axis indicates the food source’s direction in relation to the sun. The waggle run’s duration conveys distance; a longer run signals a farther destination.
Beyond the waggle dance, honeybees use chemical signals called pheromones for communication. Alarm pheromones, released by guard bees, alert the colony to threats, mobilizing defense. The queen bee produces a specific pheromone that regulates hive activities and reinforces her presence. Waggle-dancing bees also produce hydrocarbons that act as olfactory cues to guide nest mates to the foraging site.
Ecological and Agricultural Importance
Western honeybees play an important role in both natural ecosystems and agriculture. Their primary contribution is pollination, the transfer of pollen between flowers, enabling plant reproduction. Honeybees are important pollinators for wild flowering plants, supporting biodiversity and natural habitats.
In agriculture, their pollination services are significant for food production. They pollinate a substantial portion of global food crops, including many fruits, nuts, and vegetables. Crops like almonds, apples, blueberries, cucumbers, melons, and squash rely heavily on honeybee pollination. In the United States alone, honeybee pollination adds an estimated $15 billion annually to crop value.
Beyond pollination, honeybees provide valuable hive products. Honey, the most recognized product, is a concentrated energy source for bees; excess is harvested for human consumption. Other products include beeswax, used in candles and cosmetics, as well as propolis, royal jelly, and pollen, collected for their nutritional or medicinal properties.
Major Threats to Survival
Western honeybee populations face multiple threats that contribute to colony losses worldwide. One significant concern is Colony Collapse Disorder (CCD), first reported in 2006-2007. CCD is characterized by the sudden disappearance of adult worker bees from a hive, leaving the queen, immature bees, and ample food stores, with few dead bees found nearby. While initial reports were alarming, documented cases of CCD have since declined, though overall colony losses remain a concern.
Parasitic mites represent a significant challenge. The Varroa mite, Varroa destructor, is devastating. This ectoparasite feeds on the fat bodies of adult and developing honeybees, weakening their immune systems and transmitting viruses. Untreated Varroa infestations can lead to colony mortality within six months to two years. Another mite, Acarapis woodi, threatens bees by infesting their tracheal systems.
Pesticides, particularly systemic insecticides like neonicotinoids, are implicated in honeybee decline. These chemicals can be absorbed by plants and present in pollen and nectar, exposing foraging bees. Exposure can lead to disorientation, impaired foraging, reduced immune function, and colony weakening or death.
Habitat loss and degradation also stress honeybee populations. The reduction of diverse floral resources due to urbanization, monoculture farming, and land use changes limits pollen and nectar availability.
Climate change adds to these challenges by altering flowering patterns, creating mismatches between bee emergence and floral availability, and potentially expanding pest and pathogen ranges. Other factors include emerging diseases like Israeli Acute Paralysis virus and the gut parasite Nosema, and stress from long-distance transport for commercial pollination.