When we look at a single honey bee we see a small, seemingly simple creature. But behind that modest frame is an incredible story. From the very start of its life, the bee has a fascinating journey. In this lesson, we looks at the story of the honey bee, from egg to adult.
Let's start off with....controversy!
When/if you join a beekeeping club (we'll talk about that in another lesson), here's a suggestion. Stand in the middle of a meeting and introduce yourself by saying "I believe there are <x> castes of honey bee". Whether you replace <x> with 2 or 3, you will make some friends. Unfortunately, you will also upset a few folks!
The definition of a "caste" spurs quite some debate among more scientifically-inclined (some would say "geeky") beekeepers. The issue boils down to whether you think a drone counts as a caste.
Here is one definition of caste...
"...a group of individuals of the same sex that behave similarly to each other but differently from other members of their sex."
For our female bees - as will discover in subsequent lessons many times over - it is clear that the behaviors of worker and queen bees are so different that they are unambiguously castes. One gender, two distinct sets of behaviors = two castes.
With drones.... it's not so obvious.
Drones are drones. They are the same sex and basically act the same way! The question, then, is whether drones "add one" to the number of castes.
There are many who will tell you that since there is no subset of drones that acts differently to all the other drones, there is no such thing as a castes with drones. No differentiation, therefore no castes.
Technically and scientifically, that is probably accurate. But with females "contributing" two castes - since there are two sets of behaviors - it seems logical and natural to think of the drone as a single caste. And we know we will burn a few bridges here!
So, being the rebels we are, we're going to refer to three castes in the hive, not two! It's just a more intuitive approach to us and lends us a convenient terminology when referring to "the three castes of honeybee".
But know that referring to 2 castes will be important to a lot of beekeepers you meet. And we're betting some will comment to this lesson! If you want to go with that, we're cool with that too.
OK, so moving on...
Before we discuss the life cycle in detail, take a look at this extraordinary time-lapse video from National Geographic, illustrating the beautiful transition from egg to adult bee.
Note: The eagle-eyed among you may be able to spot one of the biggest threats to bees today - the varroa mite.
The timeline associated with the life cycle of the honey bee is not merely a curiosity to the beekeeper. An effective beekeeper has a keen awareness of the life cycle of each caste. Why? Let's call it forensics.
Where possible, visual evidence is preferred during the inspection. But that's not always feasible or necessary. For example, on each inspection you will hope to visually locate the queen. This is always comforting. But among 60,000 or more bees that's not always a simple task, particularly to the new beekeeper. A marked queen will help with the search but it can still be a challenge.
So, is it essential to locate the queen on every inspection? Absolutely not.
You do not need to spot the queen on every inspection! That's where the forensics come in.
As we will see, the life cycle of the honey bee has a well-defined timeline, from egg to adult. This varies across castes but there's a general pattern that can be assumed.
As an example, if you search for your queen, you can't find her, but you DO find eggs then you know she's been there very recently. It is this type of assessment and interpretation, across many scenarios, that makes beekeeping fascinating and fun
But in the situation above, just how can we assume the queen must have passed by to lay those eggs? Let's see...
A quick refresher. The queen spends her life, after her mating flights, laying eggs. She lays around 2,000 per day. The deciding factor as to whether an egg becomes a male or female is based on whether she fertilizes the egg. If she does so, she has laid an egg destined to be a worker or a queen i.e. a female. Otherwise the egg is destined to be a male bee - a drone.
The distinction between the two female castes - worker or queen - is made about three days after the transition to larvae i.e. about 6 days after the egg is laid. Workers, drones and queens are all fed royal jelly for their first three days as larvae. That diet is then stopped for both workers and drones. For queens, however, the royal (jelly) treatment is continued. Interestingly, the effect of this is not to "promote" queen-like characteristics, as many assume, but rather to inhibit the development of worker characteristics.
Before the transition to pupa, worker bees will use wax to cap the cell containing the larvae, where it will remain until it emerges as an adult bee.
As the pupa stage is reached and progresses, the bee within the capped cell starts taking a more recognizable bee form. Features such as eyes, legs and wings all develop and small hairs cover the bees body.
Finally, at the appropriate time, the bee will chew its way out from the capped cell. As soon as s/he is free and moving away from the cell, worker bees will clean up the cell and prepare it for the next egg.
The process, roles and efficiency of a bee society at work is amazing!
Despite these commonalities, there are distinct differences between the drone, worker and queen bees as they move towards adulthood. Let's look at these in detail.
With the notable exception of whether the egg is fertilized, an egg is an egg is an egg! All three castes start life as a newly laid egg in a cell and this initial state lasts for three days. Then differences become evident.
Note: The numbers below are typical but can vary based on various conditions and factors.
After the egg has hatched, each caste spends a different amount of time as larvae.
The duration of the pupa stage is as follows:
Add these numbers up and the time from the egg being laid to emergence from the cell as an adult bee is as follows (these are averages and variations do occur):
Curiously, the time when cells are capped by worker bees differs between castes.
The overall life expectancy of each caste also differs considerably. Indeed, for workers alone there are wide differences in life expectancy depending on the time of year.
One of the most important factors effecting the queen's survival is the viability of the colony through the winter months. The winter cluster of worker bees will protect the queen and regulate her temperature, even in the most extreme of conditions outside the hive. However, their success in surviving till the spring depends on a wide range of factors, not least of which is availability of resources (honey) within the hive.
Another very important factor for the queen's lifetime is her viability as an egg-laying machine The colony is constantly checking her output and productivity. In some cases they may decide she is not sufficiently productive - and take steps to replace her!
The expected lifetime of the worker bee also has some complications. In the summertime, workers bees will effectively work themselves to death, carrying out a large number of roles. If born any time from spring to late fall, workers will typically live around 6 weeks.
However, if a worker is born towards the end of fall or early winter, her role is quite different. These are so-called winter bees and they are charged with helping the queen survive the cold months.
Over this period the worker bee doesn't have the strenuous obligation - or even the option - to forage. For this reason, a worker bee can live up to 4-5 months through the winter.
Drones get the short straw! As something of a simplification, they have one thing on their mind - sex. They live for the chance to mate with a queen. The very act of mating is their last act and they will die after pulling away from the queen. If they don't mate, they will generally live around 5-7 weeks.
However, another eventuality awaits drones born in late summer.
Aside from the important and essential benefit of genetic diversity, drones really add little value to the colony. They don't forage or help with the production of honey in any way. But they do consume resources.
Workers are accepting of this during the summer, when such resources are abundant. But the idea of a drone being part of the winter cluster is offensive to workers - drones haven't contributed, so why allow them to stick around through the winter?
For this reason, towards the end of fall drones will be evicted by workers, to die outside the hive.
We've focused on the early, pre-adult life of the honey bee. We still have the life of the adult bee to understand if we are going to truly describe the life cycle of the honey bee. That story is just as fascinating, for the specific roles of the drone, queen and worker bees.