What Are the Biological Characteristics of Bees? A Comprehensive Guide

The biological characteristics of bees include: their developmental characteristics, their information exchange characteristics, their living environment, and more.
　　
1. Developmental characteristics of bees:
Bees are insects with complete metamorphosis, and all three castes of bees go through 4 developmental stages: egg, larva, pupa, and adult bee.
1. Developmental process: The 4 stages of a bee are all morphologically different, as follows:
(1) Egg. Banana-shaped, milky white, with a slightly transparent egg membrane; the slightly narrower end is the posterior end of the abdomen, and the slightly thicker end is the head. For an egg laid by the queen, the slightly narrower end is at the bottom of the brood cell, and the slightly thicker end faces the cell opening. The embryo inside the egg develops for 3 days before hatching into a larva.
(2) Larva. White, worm-like. At first it is C-shaped; as the body grows, it straightens out with its head facing the brood cell. During the larval stage it is fed by worker bees. If female larvae hatched from fertilized eggs are fed for the first 3 days on larval food made of royal jelly with added honey and pollen, they develop into worker bees. If the same female larvae are continuously fed large amounts of royal jelly during the larval stage, they will develop into queens.
When worker bee larvae grow to the end of the 6th day, worker bees seal the cell opening with a wax cap. The larva in the capped cell spins a cocoon and then pupates. Capped larvae and pupae are collectively called sealed brood, and a comb with mostly sealed brood is called a sealed brood comb (pupa comb). The caps over worker bee pupae protrude only slightly, so the entire sealed brood comb looks relatively flat. Drone pupae have domed caps, and their cells are larger, making the two easy to distinguish. Worker bee larvae pupate at the end of 2 days after being capped.
(3) Pupa. The pupal stage mainly involves remodeling and differentiating the internal organs to form the various organs of the adult bee. The head, thorax, and abdomen gradually become visible, the appendages also appear, and the color gradually darkens from milky white. When the pupa is fully developed, it sheds the pupal shell, bites through the cell cap, and emerges as an adult bee.
(4) Adult bee. A newly emerged bee has a relatively soft exoskeleton, very tender body surface hairs, and a lighter body color. Before long the skeleton hardens, the four wings straighten, and the various internal organs gradually mature.
2. Developmental periods of the three castes of bees: During embryonic development, bees require certain living conditions: suitable brood cells, suitable temperature (32-35°C), suitable humidity (75%-90%), and regular feeding with sufficient food. Under normal conditions, the developmental period from egg to adult bee is generally the same for bees of the same variety. If the nest temperature is too high (above 36.5°C), the developmental period will be shortened, or development may even be abnormal, with curled wings or death midway; if the nest temperature is too low (below 32°C), the developmental period will be delayed, or the bees may be injured by cold. The developmental period of the Chinese honey bee (abbreviated as Chinese bee) is slightly shorter; the developmental period of the Chinese bee worker is about 20 days, while the developmental period of the Italian bee worker is 21 days.
By mastering the developmental dates and understanding the ratio of unsealed brood combs (egg and larva combs) to sealed brood combs in a colony (the ratio of eggs, larvae, and pupae is 1 to 2 to 4), one can tell whether the colony's development is normal. By mastering the developmental dates of the queen and drones, one can arrange the work schedule for artificial queen rearing.
　　
2. Information exchange characteristics of bees ---- bee pheromones:
In their social life, bees have formed an information exchange system that can adapt to survival and solve problems. In order to survive and develop, the entire colony can carry out activities in an orderly and coordinated manner. Here we mainly introduce bee pheromones.
Bees live year-round in the dark hive. In addition to relying on contact, sound, and dance for communication, much information is transmitted through chemical substances. Pheromones are chemical substances secreted outside the body by insect exocrine glands; through contact between individuals or transmission through the air, they act on other individuals of the same species and trigger specific behaviors or physiological responses, so they are also called ectohormones. For individuals of the same species, the pheromones transmitted between them are a special "language"; the receiving individual can understand the information code contained in them, thereby producing behavior or physiological responses beneficial to the colony.
(1) Queen pheromone: When a colony has an egg-laying queen, the bees' activities inside and outside the nest are orderly. Once the queen is lost, the worker bees' foraging activity drops sharply, and many worker bees crawl around chaotically inside and outside the nest. This shows that worker bees learn of the queen's presence through some kind of information.
① Queen mandibular gland pheromone: The main functions of queen mandibular gland pheromone are: it is highly attractive to worker bees; it can inhibit the development of worker bee ovaries and prevent the building of queen cells; when released in the air, it can induce drones to become sexually excited. Attendant bees obtain mandibular gland pheromone from the queen with their mouthparts or antennae, and then, acting as messengers, pass the pheromone to other worker bees through food.
② Queen tergal gland pheromone: It is unique to the queen and absent in worker bees. Its main function is to let worker bees recognize her signal, and it also inhibits the building of queen cells and prevents the development of worker bee ovaries. When the queen is within 30 cm of drones in the air, the tergal gland pheromone is strongly attractive to drones and can also stimulate their mating activity.
③ Tarsal gland pheromone: The tarsal gland secretions of the queen and worker bees are also called footprint pheromone. It can inhibit strong colonies from building queen cells.
④ Koschewnikow gland pheromone: It is highly attractive to worker bees.
⑤ Rectal pheromone: The feces of virgin queens aged 1-14 days contain o-aminoacetophenone, which has a repellent effect on bees.
(2) Worker bee pheromones
① Worker bee mandibular gland pheromone: When foreign worker bees (robber bees) invade, or when a foreign queen enters the hive, bees often bite the intruder with their mandibles, marking the "enemy" with 2-heptanone and guiding other bees to attack. Worker bees of the same colony that receive this pheromone often also secrete 2-heptanone, increasing its concentration and attracting more aggressive worker bees.
② Alarm pheromone: The main component of the alarm pheromone secreted by the Koschewnikow gland in the worker bee's sting chamber is isopentyl acetate. When stinging, it remains on the "enemy" and can attract more bees to sting. Its activity is more than 20 times higher than that of 2-heptanone.
③ Nasonov gland pheromone: Its main components are aromatic oxygen-containing terpenes. It is a navigation signal that guides bees to the hive entrance and guides bees to fly to food sources. It can adjust the movement of a swarming cluster, causing a queenless cluster to move toward a queenright cluster, and guide scattered bees to find the queen; together with queen mandibular gland pheromone, it stabilizes the swarming cluster.
④ Worker bee tarsal gland pheromone: Worker bees apply tarsal gland pheromone at the hive entrance to guide bees of the same colony to find the entrance. Worker bees also seem to mark collection sites with tarsal gland pheromone to strengthen their attractiveness to other foragers.
⑤ Beeswax pheromone: Newly built combs have a special fragrance, whose main components are volatile aldehydes and alcohols. It can stimulate bees' foraging and storage behavior.
(3) Drone pheromone: Drone pheromone is also produced by the mandibular gland. During mating flights, sexually mature drones fly in groups above a chosen location and release pheromone to attract virgin queens to fly over.
(4) Brood pheromone: Its main functions are: inhibiting the development of worker bee ovaries; enabling worker bees to "smell" the presence of larvae, making it easier for worker bees to distinguish drone larvae from worker bee larvae. The pheromone of mature larvae prompts worker bees to seal their cells with wax caps to facilitate pupation. It can also stimulate bees' foraging and activate the worker bees' hypopharyngeal glands.
A deep understanding of bee pheromones can help us understand many complex bee behaviors so that these pheromones can be fully utilized in production.
　　
3. Characteristics of bees' living environment
The external environment has many major effects on bee life. These mainly include the effects of temperature, humidity, light, and other climatic factors.
1. Temperature:
Bees are poikilothermic animals, yet a colony formed by thousands of bees has the ability to regulate body temperature that is unique to homeothermic animals. The more bees there are, the more stable the temperature inside the hive, and it can be maintained within the suitable range of 34°C-35°C. Too high or too low a temperature is unfavorable to their development and reproduction. For example, at 27°C, sealed brood can still emerge as adults, but they have no foraging ability; at 30°C, emergence is delayed by 4 days; at 37°C, the emergence period is shortened by 3 days, but large numbers of sealed brood die (brood is seen but no bees). The most suitable temperature for bee life is 15°C-25°C. When the air temperature is 5°C-35°C (shade temperature during the day), bees can leave the hive and be active. If the air temperature remains below 10°C for a long time, the queen stops laying eggs, bees reduce or stop leaving the hive, form a cluster inside the hive, and enter the broodless overwintering period. In temperate regions, the queen stops laying eggs in winter, only old bees gradually die, no new bees emerge, and the number of bees in the colony gradually decreases; in summer, the queen's daily egg laying often exceeds 1,500 eggs, the number of newly emerged bees greatly exceeds the number of dead old bees, the number of bees gradually increases, and the colony reaches its peak.
Temperature varies greatly throughout the four seasons. In order to survive, bees regulate the temperature inside the hive in various ways. In hot summer, when the temperature inside the hive exceeds the suitable range, bees go out to collect water and evaporate water (fan their wings) to cool down. When the hive is exposed to the scorching sun and radiant heat is too high, bees leave the comb, gather in the larger spaces inside the nest, and pile up at the hive entrance to dissipate heat; in production this phenomenon is called "leaving the comb." Conversely, when cold weather comes, bees leave the outer combs and gather on the brood combs in the center of the hive to protect the brood, which in production is called contracting the cluster. In severe winter, the colony clusters to overwinter. The suitable temperature at the outer edge of the cluster is 6°C-10°C, and the suitable temperature at the center of the cluster is 24°C-30°C. If insulation is improper, bees regulate temperature through behaviors such as eating honey, moving, and breaking up the cluster. Because metabolism increases, this not only affects the lifespan of bees but also increases feed consumption.
2. Humidity:
The relative humidity of the air inside the hive is related to the temperature and humidity of the outside air, the temperature maintained inside the hive, the physiological condition of the bees, and the number of developing individuals. The relative humidity in the center of a normal hive is 77%-84%, and humidity in various parts of the hive varies between 25%-100%. During the honey flow period, the humidity in the center of the hive is 55%-60%; if there is no honey flow in nature, the relative humidity between brood combs is 76%-91%, because rearing brood requires higher humidity, while honey ripening requires lower humidity due to the evaporation of excess water in the collected nectar. The most suitable relative humidity during overwintering is 75%-80%. If the inside of the hive is dry, water in the bees' bodies and in the comb honey evaporates quickly, and the bees feel thirsty and become restless, leading to overwintering failure. In addition to using metabolic water, bees collect water and spray water droplets to evaporate water and raise the humidity inside the hive, and fan their wings to lower the humidity inside the hive.
3. Effect of light:
Sunlight can stimulate bees to go out. The foraging season is the long-day season of the year. Beehives should be placed in shady places, with the entrance facing south. Bees also show phototaxis at night, so they should be kept in a dark environment at night.
4. Other climatic factors:
Bees require flowing fresh air for life. When air is not circulating, the colony easily becomes restless, and especially hot and stuffy conditions are even more dangerous. Showers or sudden exposure to the sun also have a great impact on the safety of bees going out. In coastal areas where strong winds are frequent, bees are forced to fly close to the ground when foraging. Therefore, when choosing a site, attention must be paid to wind force, wind direction frequency, and the natural or man-made barriers in the area.