A neighbor calls you that there is a bee swarm on a low-lying branch of her lilac bush. Would you come and get it? Free bees? You bet! Being a good beekeeper you have the necessary equipment on hand to handle a new colony including a suitable box and drawn comb (I told you it is a fairy tale). So you go get the bees, install them in your well-prepared box and bring them home.
Because the bees like their new home, the queen starts laying immediately. Bees that have just swarmed have their little honey bellies well stocked with provisions to take care of new brood so all is well. Even so, some of the bees may start out looking for more nectar and pollen - it's just their natural calling.
So, a mathematical question. After that first day, how many eggs will be in the hive? Don't make it too hard - lets just say there are one days worth of eggs.
The queen continues to lay on the second day and at days end, same question. How many eggs are in the hive? Duh! two days worth.
Third day? Three days worth!
Fourth day - Be careful! There are only three days of eggs, not four. Why? The eggs laid on the first day have hatched and are now new larvae. The moral of this fairy tale is there will never be more than three days worth of eggs in a hive.
So, at the end of four days what do we have? Three days worth of eggs and one day worth of larvae. I think you can see where this is going. Let's jump ahead to the end of the ninth day. There will be three days worth of eggs and six days of larvae, right?
Now, at the end of the 10th day, what do we expect? Seven days of larvae? Wrong! When larvae have spent six days as larvae they spin a cocoon and enter the pupa state. The bees cover them with a cap and they undergo the metamorphosis that changes them to the adult form of bee. So now we understand that there will never be more than six days worth of larvae in the hive (along with a maximum of three days worth of eggs).
To speed this up, we can see that every day a days worth of larvae will "graduate" to the pupal state and the number of days of capped brood in the hive will steadily increase. Up to a point, that is. After 12 days as pupae, fully transformed pupae will emerge as adult bees. There will never be more than 12 days worth of capped brood in the hive.
To summarize our final lesson from this fairy tale, the maximum amount of brood in a hive will never exceed 21 (3+6+12) days worth of eggs laid by the queen. Interesting, but how can we use this knowledge to better manage our bees? Let's see.
First, to close the loop on the pipeline analogy the process of producing new worker bees in a colony is very similar to a pipeline. What comes out depends upon what went in earlier (21 days in this case). Until the pipeline is full, nothing comes out and this is important to remember when we are waiting for our bee population to increase after a new start (which could be with a new swarm, package, or nuc or just after a long winter of inactivity by the queen). Patience is called for during this interval. To preview a more advanced topic which will be dealt with later, it is important to see that should the queen stop laying, there will still be a period of continued new bee production until the pipeline empties (the beekeeper might stop the queen from laying in a particular hive by removing her and starting a new split, for example).
We avoided the hard mathematics above by just counting the number of eggs, larvae, pupae in terms of a days worth of laying. To get to a more useful measure we need to know (or guess) how many eggs a queen can (and/or does) lay in a day. It seems clear that a queen may lay less than what she is capable of due to many factors - the season (winter for example), available empty comb to lay in, available nurse bees to care for the brood (even though she may lay more eggs, it is only the ones that survive that do us any good), food to feed the larvae, etc. Some of these things are somewhat in the control of the beekeeper. The beekeeper can give more space for the queen to lay in if it is short. Likewise, the beekeeper can provide food if it is short. How, and when, to do these things is part of managing bees and I believe many, many cases of "poorly performing" queens can be due to the ignorance or malfeasance of the beekeeper.
The literature reports examples of queen laying prowess as large as 3,500 eggs per day. A colony that has 3,500 bees emerging from the "pipeline" every day will definitely be a "boomer" and is much to be desired by every beekeeper. It seems that most beekeepers don't see this sort of performance and one has to ask is it a freak occurrence or is it a sign that the beekeeper hasn't got it right yet? It is clear (to me, at least) if the beekeeper has only allowed for, say, 500 eggs per day in his/her management practices, that's the most that he/she can expect. So, what management guidance can we derive from all this?
Hard to say, but let's say we don't want the queen to be squeezed to fewer than 2,000 eggs per day. That's a pretty nice pipeline and we may not achieve it but at least we won't be at fault (barring other screwups). The practical question to answer is how many frames should we provide the bees for the queen to be able to lay 2,000 eggs a day without interruption?
Consider that a deep frame contains about 3,750 cells on each face (7,500 total in the frame). For a medium frame the numbers are 2,500 per face, 5,000 total. Typically, only an oval-shaped area will be used as the corners are likely to have pollen and nectar stored in them so a fair estimate of brood space would be, say, 80% or 3,000 per face for the deep frame and 2,000 per face for the medium frame. At 2,000 eggs per day it would take the queen three days to fill a deep frame but only two days to fill a medium frame. As we have seen there will never be more than 21 days worth of eggs so the queen will need 7 deep frames or 10 1/2 medium frames to be fully occupied laying eggs.
Of course, the queen doesn't fill one frame after another. The nurse bees have to keep the brood warm and the most energy efficient way to do that is to have the brood distributed in a spherical volume which is what the bees naturally try to do. So the brood nest will be approximately spherical somewhere in the middle of the box we give them (it may be a squashed sphere, kinda like a pumpkin if the box is wider than it is high) and the frames in the middle of the brood nest will be more fully occupied by brood than those on the edges. Think of slicing a tomato vertically instead of horizontally. Bottom line, because some of the brood frames won't be filled you need more that 7 deeps or 10 1/2 mediums to hope for 2,000 eggs per day production. A good guess might be 1 1/2 to 2 1/2 times more - say 12 deeps and 18 mediums.
This is not a startling conclusion as most guides tell you that you should provide at least two deeps (or one deep plus one medium) as a brood box or three mediums. At least we now recognize that in such an arrangement we will never see a 3,500 egg per day growth rate.
But even so, we may still find our queen squeezed for laying room. Why? Because bees LOVE nectar and they will not pass up a chance to gather it if it is available (this includes sugar water that the beekeeper may make easily available) - unless their little honey bellies are already full, but that's for another fairy tale. When they bring it back into the hive they need some place to store it and, without going into all the details now, they will put it in whatever empty cells they can find. That includes newly vacated cells from emerging bees. Thus, when the foraging force is strong and the nectar sources are plentiful any nectar brought in that doesn't immediately go into the mouths of the ravenous larvae will be stored. That means that even more space must be given and the timing can be critical. The literature is full of advice on when to add honey storage and your mileage may vary! But, bear in mind, if you get behind with a strong hive and a good nectar flow, the brood nest may/will get back filled and your strong hive will suffer a diminished output from the pipeline later on and your forage bees will still be dying from exhaustion if nothing else. Not good.
New bottom line, you will need even more frames that just enough to occupy 21 days worth of brood. Exactly how many will depend upon lots of factors, but it would appear to be prudent to have more than fewer, that is, if you want maximum production from your bees. You can, of course, manage for less - your choice.
To follow up on this last point we can ask what if our 2,000 egg per day queen (or, even worse, our 3,500 egg per day queen) only has enough room to lay for, say, 15 days. She will have to stop laying for at least six days! Ouch! The pipeline will not be fed and, worse yet, we may conclude that she is a poor queen and assassinate her (in an attempt to replace her). Not a very good treatment for a royal lady and it's all our fault in the first place.
- That this is not a fanciful analysis is confirmed by innumerable references in the literature to beekeepers who keep reserve queens in small nucs where they clearly cannot reach whatever potential they have. Yet when these queens are placed in full hives, their production rises to the capabilities provided by that hive.
It might be interesting to consider some of the other implications of this analysis. In particular, for the happy case of a 2,000 egg per day rate that translates to 6,000 eggs, 12,000 larvae and 18,000 pupae in the hive at any given time. Six thousand larvae are a lot of hungry mouths to feed every day and it is in the nature of bees to take care of them as best they can. It takes a lot of foragers full time to supply these needs and until the pipeline output exceeds the daily death rate of the foragers, no surplus nectar is likely to be produced
Somewhere in these facts lies the explanation of why some hives seem to be surviving well, but still not producing surplus. At the considerable risk of disturbing the brood nest, the beekeeper can count the number of faces of capped brood (may have to estimate by fractions of a face) to get an idea of the average daily production. Just multiply the number of faces by 2,000 or 3,000 (for mediums or deeps) and divide by 12. You might also look to see if the bees are backfilling the brood nest with nectar.
On the bright side, a full pipeline means that within 21 days some 42,000 new workers will emerge. That can explain why hive populations "suddenly" explode.
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