Beekeeping Basics 4 – Honey Bee Biology

Classification

Kingdom: Animalia (Animal)

Phylum: Euarthropoda (Arthropod)

Class: Insecta (Insect)

Order: Hymenoptera (includes: wasps, bees, & ants)

Family: Apidea (largest family of bees)

Genus: Apis (Latin for Bee)

Species: Millifera (Latin for Honey Bearer)

The Caste System

Honey Bees live in a social community collectively called a colony.  The job of each individual depends on the type of bee or caste. Within the bee caste system there are 3 types of bees (Queen, Worker, and Drone).  The Queen is the only bee that can lay fertilized eggs.  When a Queen is present within the hive the hive is called “Queen Right”.  There is only 1 Queen in a colony, and the fertilized eggs that she lays turn into Worker bees.  Worker bees are the labor force for a colony.  Workers are all female, and they perform nearly all services that the colony needs.  Workers will decide when and where to move, clean, feed, care for young, forage, and defend.  In late fall, workers will also carry out the task of killing off the Drones before winter arrives.  Drones are male bees.  Drones do not have stingers.  The only purpose for a Drone is to be available to mate if an unmated Queen flies through the apiary.  Drone bees are the result of unfertilized eggs, which may or may not be from the Queen.  Worker bees (all females) are capable of laying unfertilized eggs that become Drones when a Queen is absent.  A healthy hive should consist of 5% Drones.  A large number of Drones present may indicate that the Queen is missing from the hive and the hive is then called “Queenless”.  

Metamorphosis

Metamorphosis is a biological transformation process that changes the cell structure of bees from larva (immature) to adult (mature).  This process happens during the pupa stage (capped cell) of development.

Worker bees between the ages 1-11 days old are often referred to as nurse bees.  At this age, the nurse bees are responsible for caring and raising young larval bees.  All bees start life as an egg.  Three days later the egg hatches and the larval stage begins.  All bees spend 6 days in the larval stage.  Nurse bees will check each larva every 2 minutes to ensure they are all fed.  Over this 6-day time frame, it takes a total of 2 hours of feeding-time to raise each larva.  At this point, nurse bees will cap the cell with wax and metamorphosis begins as the bee enters the pupa stage.  Each pupa is responsible for spinning a silky cocoon inside the cell.  A cocoon helps the cellular transformation process by allowing the pupa to twist and turn inside the cell without sticking to the wax walls.  The pupa stage is the only stage that has differences in development times depending on caste.  A Queen bee will emerge from pupa as an adult after 7 days, and her total development is 16 days.  Worker bees will emerge from pupa as adults after 12 days for a total development time of 21 days.  Drone bees remain in the pupal phase for 15 days and have a total development time of 24 days.

Worker Responsibilities By Age

As a Worker honey bee ages, her job changes both inside and outside the hive.  It is important to note, if a catastrophic event like poisoning, freezing, or storm damage were to kill off bees of a particular age range, then the older bees can revert back to any of their previous responsibilities.  However, their efficiency is reduced when reverting responsibilities because bees undergo a number of internal physiological changes as they age to maximize their efficiency of their duties.

Post emerging from the capped cell:

Days 1-2: the honey bee’s job is to clean cells and warm brood.

Days 3-5: the bee’s hypopharyngeal glands will stimulate the bees to feed older larva and Queen.

Days 6-11: the hypopharyngeal gland is most productive, and bees will produce proteins needed for feeding younger larva.  In addition, their wax glands will allow them to produce enough wax to cap cells.

Days 12-17: the wax glands are at peak production.  These bees will build comb, add to existing structure, transport food, regulate hive temp, and circulate air within the hive.

Days 18-21: bees focus on guarding the hive entrance.

Days 22-45: this is the remainder of the bees life, she will be foraging outside the hive for nectar, pollen, water, and propolis

Queen Responsibilities

A honey bee colony will have one Queen. She is the star of the hive, only because of her primary responsibility of egg-laying. She does not have any royal powers over the members of the colony. However, the Queen’s presence provides pheromones called “Queen Substance” which prevents Worker ovaries from developing. The Queen is largely controlled by Workers who tell her when and where to lay eggs, including manipulating the size of the cell to entice the Queen to lay unfertilized (Drone) eggs. In her life, the Queen will leave the hive for two reasons. First, a new Queen must go on mating flights. This is the only time in her life that she will have an opportunity to mate and store sperm from an average of 12 Drones over 1-3 flights. The second reason a Queen will leave the hive is when the hive decides to swarm. When making this decision, the Queen must choose to either fight-to-the-death with a daughter Queen, or leave the hive in a swarm. Click here if you’re interested in learning about swarms and capturing swarms.

Drone Responsibilities

The primary responsibility for a Drone is to mate with a Queen. Drones are male bees that are found hanging around hives during spring and summer months. Drones regularly leave the hive to fly in what is known as Drone Congregation Areas (DCAs). Once at the DCA, Drones from many hives will fly together, like a pack of wolves, in the hope of spotting a virgin Queen. Once a Queen flies into the DCA, and is noticed, she is chased by hundreds or even thousands of Drones seeking to mate with her. The competition is fierce, and only the most fit males with have the chance to out-run all others for the chance copulate with a Queen before she makes it back to her hive, where her Workers are ready to protect her from the chasing Drones. Flying around in high-speed pursuits chasing Queens requires a lot of energy. Throughout the day, Drones will frequently fly home, or to the closest hive that accepts them, to be fed a meal of honey by the Workers. I know what you are thinking, and yes, Drones are deadbeats!

Honey Bee Anatomy

Head

Like humans, honey bees use their head as an instrument for sensing the world and decision-making.  Honey bees have 2 different types of eyes known as compound and ocelli.  Compound eyes are large dark regions located on both sides of the head and are made up of thousands of individual eyes, depending on the caste of the bee (Queens have 4K, Workers have 6K, Drones have 8K).  Ocelli are 3 smaller structures (each an ocellus) located at the top of the head, and their function is thought to help bees detect polarized light used for navigation.  For more information about this topic, check out this link: http://www.polarization.com/eyes/eyes.html

Thorax

Attached to the thorax, bees have 2 pairs of wings and 3 pairs of legs on each side.  The wings, set in pairs on each side of the thorax, can be operated individually for air flow in the hive or each pair can be fused together for flight.  The legs are very versatile, with claws that allow bees to have good grip on rough surfaces, like tree trunks, yet with a pad-like lobe (called an Arolium) that enables bees to walk on smooth surfaces – leaves or even glass!  There are also special pockets in the joints of the hind legs called the Pollen Press and hair-like structures surrounding the joint that help bees collect and carry more pollen while foraging, and is collectively referred to as a pollen basket or pollen pouch.

In order to fly, a Worker bee must maintain a thorax temperature above 27°C (81°F).  Flight muscles cooler than this simply cannot generate enough wingbeats for takeoff and flight.  On cool days, bees have evolved a preflight warm-up of the flight muscles to compensate.  They warm up these flight muscles with a series of rapid contractions of muscles located in the thorax.  This muscle activity generates heat from the thorax, allowing the bee to fly on cool days.  The entire colony can do this inside their nest to regulate hive temperature, too. 

Sometimes, foraging bees don’t make it back to the hive before the weather conditions change.  If the temperatures drop too low, the bee may not be able to fly back to the hive.  A bee chilled below 18°C (64°F) cannot generate the neuronal activity to activate their flight muscles and produce more heat.  In this situation, the bee must wait to be warmed up by a change in the weather conditions before she can resume flight back to the nest.   

Abdomen

The abdomen is the part of the bee’s body that contains the honey crop, digestive organs, reproductive organs, wax and scent glands (Workers only), rectum, and the stinger (Workers and Queen only).  Bees can control what passes from the honey crop into the digestive system, and will only allow this passage when feeding.  The honey crop is where foragers store the liquid resources they harvested for the return travel back to the hive.  When full, the honey crop can hold up to 50μL(microliters), which is about 80% of the bee’s weight.  On the other end of the abdomen, the rectum stores the bee’s digested waste.  Healthy bees will only defecate while in flight, and typically, healthy bees do not defecate inside their hive.  During winter months, bees store their digested waste in their rectum.  They must wait until outdoor temperatures are above 7°C (45°F) before they can leave the hive to defecate.  These flights are called “Cleansing Flights” and are performed to alleviate digestive waste buildup.

Works Cited

Nelson, D L. 1998, Beekeeping in Western Canada. , n.d.. Print.

Seeley, T. D. 2019, The lives of bees: The untold story of the honey bee in the wild.

Tarpy, D. R., Page, R. E., 2000, No Behavioral Control over Mating Frequency in Queen Honey Bees (Apis mellifera L.): Implications for the Evolution of Extreme Polyandry, The American Naturalist, Vol. 155, No, 6.

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