Bee Lifecycle

Bees being insects have a lifecycle that is nothing like a mammal that we are more familiar with.  In fact, being social insects they are different to most other insects as well.  Bye and large, female insects lay their eggs in large numbers and abandon them.  They rely on the large numbers so that a few of them may survive.

Bees do not function this way.  They build a brood comb for each individual egg and carefully tend it.  Bees are very good and attentive parents.  The lifecycle starts with the Queen Bee laying an egg in the bottom of one of the cells of the brood comb.  She then leaves it to the care of the nurse-bees to raise it to adulthood.  Her duties are solely egg-laying.  A good Queen may lay 2000 eggs per day – day in day out.  She can lay her own bodyweight in a day.  She has no other duties.  She is a veritable egg-laying machine.  When her egg-laying falters the worker bees will raise another queen to replace her and kill the old queen.  Bees do what is best for the colony and are not over-given to sentimentalism.

The egg laid in a cell may be fertilised or unfertilised.  Which she lays is determined by the size of the cell.  If the cell is slightly bigger than normal, she will deposit an unfertilised egg which will develop into a drone (male).  A drone therefore has a mother but no father.  It carries only its mothers genes.

If the cell is a regular size the Queen lays a fertilised egg which under normal circumstances develops into a worker bee.  This is a sterile female.  The egg is about the size of a grain of sand and takes about four days to develop into a larva.  To us, this is a “grub”.  To a bee this is their young and they will defend it with their life.  For the first four days they feed it with a special nutrient (Queen Bee Jelly) that is full of concentrated nutrition and hormones produced by a special gland in the nurse-bees hypopharynx.  After four days they switch to feeding it honey.  This switch makes the developing bee sterile but still well-capable of worker duties. 

If for any reason a hive has lost its Queen (or the Queen is deficient in her egg-laying duties) it is necessary to produce a new Queen.  To achieve this the workers select a number of larvae and feed them continuously on Queen Bee Jelly.  On this rich nutrient the larvae develop quickly as Queen-larvae which are fertile females.  The Queen larvae are larger than worker larvae and to accommodate them the workers enlarge the cell.  A Queen cell is not only larger, it is very characteristic in shape and easily identified by the beekeeper.

After a further 12 days the larvae have grown considerably and are ready for the next stage in their life-cycle.  They spin a cocoon of silk around themselves inside the cell and start the process of development from a larva into an adult.  When this process starts, they are very vulnerable and the worker bees cover the cell with a protective cap of wax.  This cap is artfully made to be permeable to air so the cocoon does not suffocate.

After a further 12 days the larva has morphed into an adult in one of the greatest transformations in nature.  The young bee bites its way through the wax cap of its cell and emerges.  If it is a Queen it will first seek out any other Queen cell and sting it to death through the side of the cell.  (Definitely no sentimentality here).  She will be ignored by the worker bees for a few days until she becomes sexually mature.  She is then a “Virgin Queen”.  When sexually mature she will be taken on a mating flight by the worker bees.  They will go to a Drone Congregation Area (DCA) for the mating.  This is usually high in the air above a distinguishing geographic feature.  This is where drones go seeking to mate with a Virgin Queen.  When she arrives, she flies higher and higher and only the strongest and fittest drones will be able to keep up with her.  She then mates with between ten and twenty of them.  At the consummation of each mating the drones private parts are ripped off and he falls dead to the ground.  (Their mating organ is left in the Queen).  Drones spend all their lives trying to mate (and die if they achieve it – not much of a deal!!)

The mated Queen returns to the hive and is closely inspected by the worker bees.  If they determine that she is not adequately mated, she will be taken out again to the DCA for another session.  If they decide that she is adequately mated, she starts her duties of egg-laying.  The sperm acquired at the DCA is stored in a special pouch (the spermothaeca) in the Queens abdomen.  The sperm is kept live and viable for the rest of her life.  She will never need to mate again.  She may live for four years but the sperm from her mating flight remains in her for life.  What is quite remarkable is the fact that she can control the dispensing of microscopic amounts of sperm.  Thus she can choose to lay a fertilised or unfertilised egg depending on the size of the cell into which she is laying.  To keep up her frantic and energy-expensive duties she needs to be fed large amounts of nutrient-rich Queen Bee Jelly.  This is provided by a coterie of attendant bees, who’s exclusive duty it is to attend to the needs of the Queen.  She cannot feed herself but must be fed solely by these attendants who also remove her waste.  Nothing is allowed to distract from her from her frantic egg-laying duties. Eventually her energies wane and her egg-laying slows.  When this falls below a critical level she is killed and replaced.  There is never a graceful retirement for a Queen Bee.

The life of a worker bee is quite different.  On hatching it becomes a “nurse bee” maintaining the combs, cleaning, feeding and looking after the larvae.  As time passes and the nurse bee becomes more mature it may be allocated a specialised task.  It could be a comb-builder, a Queen attendant, a guard bee, or a “tanker bee”.  These leave the hive to find water and carry it back to the hive in their “honey stomach” where it is used to air-condition the hive.  The tanker bees spread it on the combs and the nurse bees evaporate it by fanning it with their wings.  This evaporative cooling controls the temperature and stops the developing eggs and larvae overheating.

Conversely – some bees are allocated duties as “heater bees”.  When the temperature in the hive falls too low, the eggs and brood are at risk of dying through chill.  The heater bees enter cells in the comb.  They have the ability to unlatch the major muscles that drive their wings.  Therefore, they can do the muscular equivalent of flying without their wings moving.  This generates body heat which is transmitted to the surrounding comb.  Thus the worker bees can quite closely control the temperature of the hive to the optimum of 37C.

When a worker bee has done its apprenticeship in the hive, it ventures outside to become a forager.  On a warm sunny afternoon, it is usual to see a small cloud of bees flying around the front of the hive. These are new foragers learning what the front of their home looks like and imprinting it in their tiny brains.  As each has only a million neurones (compared to many billions in a mammal) this is in itself a miracle of nature.  They must learn to forage over a 28 square mile range (3 mile radius) and reliably find their way home carrying up to their own bodyweight of nectar and pollen.  This is a feat that size for size makes the homing pigeon look like a wandering vagrant.  In its foraging lifetime, an individual worker bee might make (weather permitting) a teaspoonful of honey.  In summer that lifetime may be short – as little as six weeks.  It wings become ragged and it runs out of energy.  Eventually it can no longer fly and is then – most likely – eaten by predators (usually birds).  However – given the rate of new bees being created (up to 2000 per day) a workers life could not be too long or the colony would over-run the local resources and would then starve.

It is easy to misunderstand the functions of a drone.  The mating function is overt and obvious.  But this does not appear to be the totality of their function.  It has been known for many years that drones “stabilise” the colony.  Quite how and why is still debated.  It has been demonstrated that a colony with sufficient drones is much less likely to swarm (if this happens the Queen decamps and takes half the worker bees with her.  This is obviously a “bad thing” from a honey-production perspective).  It also appears that colonies with sufficient drones are less aggressive.  The drones appear to have a calming effect.  One theory that has been put forward is that the worker bees are not asexual.  They are females that are sterile.  It is possible that they still require sexual congress with drones even though it does not involve penetrative sex.  Research into this aspect of the life of a honeybee is much needed.  What is known with a reasonable degree of certainty is that if drones are removed from a colony, the productivity of that colony will decline.  This is counterintuitive as drones do not forage but consume resources.  It appears that the presence and activity of the drones increases the efficiency/activity of the worker bees to such an extent that it more than overcomes the resources that the drones consume.

Bees have evolved their lifecycle over 180,000,000 years.  Evolution has fine-tuned them to require a precise balance within the colony for optimum performance.  To second guess nature and believe that we can improve on it without understanding the subtle ramifications of their lifestyle, may be more than a little arrogant.  Beekeepers must therefore work with nature rather than against it, to produce happy, relaxed and productive bees.