It is an interesting truth that man, in all his brilliance, depends so greatly upon a creature only a few centimeters in size. Yet, it is a truism that becomes ever more evident as bee populations struggle. To maintain our current lifestyle, with our inherent demands on the environment, it is imperative that bees reproduce on a grand scale, to deliver on their important role as pollinators.
“If the bee disappeared off the face of the earth, man would only have four years left to live.” ---Maurice Maeterlinck, The Life of the Bee
We tend to take bees for granted and their reproductive process rarely receives focus. So, let's look at the mysteries behind one of the earth’s most brilliant, important and yet tiny creatures. We explore the differences in species of bees and walk through the reproductive cycle, from conception to birth. This brings a new understanding and appreciation for this tiny but essential form of life.
Before we look at honeybee reproduction, it is worth considering that other bees reproduce entirely differently.
So, there are many differences in how bees mate. Let’s take a closer look at how this all works for honey bees.
The male bee (drones) mate with the queen one at a time, to release their sperm. The drone will fly over a queen with the intention of positioning himself such that his thorax is above her abdomen. A drone’s appendage is referred to as an endophallus, which is tucked within his body and inverted simultaneously. He will protrude his endophallus and insert it in the queen’s sting chamber.
When this happens successfully, his endophallus will flip and secrete sperm in the process. This process takes less than 5 seconds and when he disengages with the queen his endophallus will be ripped off! This means that the act of mating usually kills the drone.
Check out this fascinating video to see queens and drones mating in mid-air. And have sympathy for the drone...
A colony of honey bees revolves around the queen. But what is her role in the reproductive process?
Queen honey bees are fascinating creatures that determine the success or failure of the colony. Her oviducts hold most of the sperm she collects, equating to about 100 million sperm. This is the sperm she will use to immediately fertilize eggs. The remaining 5 to 6 million sperm will be stored in her spermathecal. This sperm will remain in good condition for up to 4 years life.
The queen will only fertilize some of the eggs she lays. When an egg moves through the vagina of the queen bee it may become fertilized, because it will press against the spermathecal duct.
The queen honeybee determines the eventual gender of each of her eggs. As the eggs move from her ovaries to oviducts she determines whether it is to be fertilized or not.
Another gender-related factor for the egg is the orientation of the cell in which the queen lays her egg. A vertical cell will be for a queen, while horizontal cells will be for either a worker bee or a drone. The nurse bees will know what each horizontal cell should hold, based upon the size. The queen and worker bees make these decisions based upon the needs of the colony.
Worker bees are female and can lay eggs as well. But because they do not take a mating flight their eggs are unfertilized and they will only produce drones. The queen is the only bee who can create both male and female bees.
In their natural habitat, queens lay differently than they do if being raised by a beekeeper. Wild honey bees create hives in locations such as trees. When a queen lays her eggs in these natural settings, she will lay them in an oval shaped cone on the roof of the hive. This is when royal jelly is applied to all eggs to keep the larvae from falling out.
If a queen lays brood inside a beekeeper’s hive, she usually picks a frame near the center of the box to begin laying. Worker bees will apply a small amount of royal jelly to stabilize the larvae on the frame.
The queen bee only has so much sperm to last her lifetime. When all the stored sperm has gone, which can take up to 4 years, the colony will begin raising a new queen.
However, this can - and often does - happen well before four years have passed. Colonies requeen their hives when they notice their old queen is slowing her egg-laying production. As the name implies, requeening is replacing an old queen with a new one.
But what happens to the original queen?
Worker bees pay very close attention to the queen. If she has a defect causing her production to drop or if her pheromone begins to lessen, which happens with age, they will consider raising a new queen. When this happens, worker bees will smother the queen to death, by balling around her so she overheats and eventually dies!
Queens have a job and the colony depends upon her doing that job. When she reaches the point where she can’t do that job effectively anymore, the colony knows what to do to continue their survival.
Life can be tough in the hive.
Drones are created from unfertilized eggs. These eggs can be laid by the queen herself or, in some situations, by worker bees, though this is not a healthy sign. Drones are created for one purpose - to mate with a queen. Let’s explore the drone’s life a little further.
The drone has quite a life. He is created with the primary purpose to mate. Drones do help regulate the temperature inside a hive from time-to-time, but mating is their true lot in life. They don’t have stingers and don’t help contribute food to the hive.
Drones live each day in the hope of finding a queen on her mating flight. Yet, when the drone tries to mate he isn’t always successful. If the queen’s sting chamber is closed the drone will still ejaculate as though he had successfully penetrated inside the chamber. Unbeknownst to him, that was his lucky day because it keeps his endophallus from being ripped off!
If he eventually mounts the queen when her sting chamber is open, he will be able to deposit his sperm for her to store. But when he does a tiny explosion takes place.
When the drone deposits his sperm into the queen’s sting chamber it must be powerful enough to flow past her sting chamber and into her oviduct, so the sperm can be stored to subsequently fertilize eggs. The drone’s sperm literally blasts through the queen’s reproductive system with such force that it will rip off the drone’s endophallus and throw him off the queen.
Drones do not usually mate with a queen from their own hive. They fly to areas known as Drone Congregational Areas (DCAs) to seek other queens.
Scientists are still struggling to locate hard evidence why drones pick particular areas to congregate. It is possible that drones choose these areas based on magnetic force. When drones are older than 6 days they have a sudden increase in magnetite within their abdomen. This could literally pull them to certain locations.
Drones return to these congregational spots year-after-year. Often, they will visit multiple congregational spots in one day, each of which can hold a few hundred to a few thousand drones at a time. It is obvious when a place has been chosen as a drone congregational area because they create a buzzing sound almost like a swarm.
These congregational areas range anywhere from 100 to 700 feet in width and are 50 to 125 feet off the ground. Drones are so focused on these areas that if a queen flies by outside of these boundaries they will completely ignore her. The drones give off a certain pheromone to draw queens to them.
Drones only have a 1-in-1,000 chance of mating with a queen, so many drones will not mate and die from the process. Some drones actually survive the mating process.
So, what happens to the drones that don’t die from mating or the ones that never get the chance? They still have a pretty grim future.
Drones that are not able to pass on their genetics - or in a freak turn of events, survive the mating process - are allowed to remain at their hive during the warm seasons. However, when winter approaches and bees must survive the winter on what they have stored, drones become just one more mouth to feed.
At this point, worker bees will round them up and kick them out of the hive. Remember, drones do not have stingers which means they have no defense system and are also incapable of collecting food for themselves. This means they die from cold or starvation.
Though these tiny creatures have such a large impact on the reproduction of bees, their outlook is certainly on the bleak side when it comes to individual survival.
So, drones have no real purpose beyond mating, essential though that is. Drones do mate with the queen, but they offer something so much more important than simply sperm.
They offer genetic diversity.
Female bees have 32 chromosomes. This means they get 16 chromosomes from their mother and 16 from their father. Drones have 16 chromosomes. Therefore, eggs only have the option of holding half of the queen’s genetics. This is significant because genetics determine how efficiently and effectively a hive runs, as well as being a factor in resistance to disease.
When the queen mates with drones on her mating flight, she benefits from the genetic diversity they offer. Each egg that hatches will be slightly different, based on its genetics. Because of this the colony has a greater potential for success.
The long-term health of the colony depends greatly upon the queen and her ability to lay eggs. When the queen is young and just starting out, she will lay her eggs in an organized fashion. She lays the eggs right next to each other, in their respective cells. As she gets older she will lay fewer eggs and have a different laying pattern.
In her prime, the queen bee will lay about 2,000 eggs per day. This is more than her own body weight in eggs. The eggs are only about half the size of a grain of rice and take a matter of seconds for her to lay. Beekeepers of a certain age often use a magnifying glass when checking for eggs!
When the eggs are laid there is a strand of mucous used to connect the eggs to the cell. Within a matter of days, the digestive and nervous systems are formed. In about three days the eggs will become larvae. Then the nurse bees will feed them and help them grow into the gender and role for which they were laid.
Three days after the queen lays an egg it will have developed into bee larvae with all major systems starting to be formed. The queen fertilizes, and lays eggs based upon cell size. The larger cells are generally for drones, while the smaller cells are for workers.
The fertilized eggs are the female bees (workers and queens) and the non-fertilized eggs are the male bees (drones). After the eggs have turned into bee larvae they are fed royal jelly. For fertilized eggs, the number of days they are fed royal jelly will decide their role as either worker or queen. Bees secrete royal jelly to feed their larvae and queen. Queens are fed royal jelly all the way through their hatching process which is 16 days.
Worker bee and drone larvae are only fed royal jelly for the first 2-3 days, with worker bees taking 21 days to exit the cell and drones 24 days.
Honey bees live for different lengths of time, depending upon their role in the hive and the time of year they are born. Let’s take a closer look at how these variables can impact the hive.
Drones do not live very long. Because their main purpose it to breed and spread genetics, they often die early in life, given that the breeding process kills them. If they are alive as the colder months approach, they face eviction from the hive and subsequent death.
The life span of worker bees varies. If they are born and put to work during the busy season, they might live to around 6 weeks or less. If they are born in a non-peak season, they might survive to 7 weeks old.
Winter bees are different! They have a higher blood protein and a fatter body, meant to produce heat for the queen. Winter bees can live anywhere from 4-6 months, through the winter.
A worker bee will collect honey from foraging bees and act as a nurse bee, tending to the bee larvae. As she gets older she is promoted to foraging bee. This wears her down quickly, as this is very physical work for such a small creature.
After her mating flights, the queen bee spends her life inside the hive, laying eggs. Her biggest danger is during her mating flights and the possibility of disease. If these threats are avoided, then she can live on for 4 years or more.
Bees have large hives during the warmer seasons. The reasons for this are simple. The more workers available, the more food can be gathered. The hive will also have greater protection against hive beetles and mites. Additionally, there will be more bees available to help with wax production, which is good for the queen as she prefers to lay in fresh comb.
Within reason, the larger the hive the better the health of the hive. Even as a hive goes into winter, bees know to downsize their numbers, so they won’t have as many mouths to feed during this time. Having a queen that is a great egg-layer is invaluable to the health of her hive.
The reproduction and life of a honeybee is fascinating. These tiny creatures face so many challenges in their daily lives. Yet, they still share the same common goal: reproduce, create a genetically strong colony and survive.