How many eggs can a queen lay.
Bee Culture – Nov., 2008
by WALT WRIGHT
Elkton, Tennessee
The word “can” is emphasized in the title of this submission. There are two kinds of “can.” The rate of eggs per day is one kind, and the total eggs the queen is able to produce in her lifetime is the other. We’ll touch on both.
Those of you familiar with my normal output will know that I am not shy about challenging “conventional wisdom” that is not supported by my personal observations. This submittal is no exception. Brace yourself for a discussion of the subject that strays from what you learned early in your beekeeping training. If you are certain that what you “know” is accurate, just flip the page, and enjoy the rest of the magazine.
We’ll start with what the experts tell us. Two “facts” that are challenged herein are that the maximum queen laying rates range from 1000 to 2000 eggs per day and that a single, deep hive body is all the room a queen needs to lay in. Those two facts will be treated in that order in this discussion: Rate first and volume second. Although rate and required volume are interrelated, we’ll try to separate the two. Life time capacity is discussed later.
The highest rate of eggs per day that I have seen in the literature is about 2000. Most literature rates are somewhat less. In a recent article by Larry Conner, the rate per day that he used was 1400. C.L. Farrar used 1600. In my opinion, these numbers are well below the actual rate per day that a quality queen can produce. It is not the intent of this submittal to promote my colony management approach, but application of that system suggests that standard management does not use the queen to capacity. My management system induces annual supersedure. In contrast, colonies managed by standard procedures often are headed by the same queen for three years. This disparity gives rise to the obvious question – Why? In the past, automatic supersedure was reported with no reasons given. I try to report what I see. If a reason is not obvious, I try not to guess. We’ll come back to this issue later.
Before we get into the numbers game, let me identify a few other unpopular opinions growing out of observations of my management system. These opinions are not found anywhere else, but significantly affect queen laying rates.
The queen is often given credit for preferences she doesn’t have. Her daughters make the judgements on where and when eggs are needed. They, the workers, know which cells have been prepared for eggs. When the workers have need of the queen’s services, they round her up (literally) wherever she is meandering and escort her to the area that is ready for eggs. Then the steering committee (court) fawns over her to induce laying. This opinion is supported by the fact that sometimes the queen can be found lumbering over empty brood comb with no interest in laying and no “court”.
The workers also determine area and its location of the active rearing cells of the brood nest. The space allocated to active brood rearing is controlled with a built-in safety margin in the volume of the brood nest that can be protected. For example, the late spring freeze seldom causes any loss to brood chilling. Their safety margin in cluster size versus brood volume normally protects the brood.
Keep in mind that the brood nest size stays in a state of change for the entire active season from start up in mid winter to close out in late fall. The changes are slow and may not be obvious to the casual beekeeper, but the changes reflect the colony objectives with the passing season. Briefly: early – build population to support reproduction by colony division; mid season – reduce population to limit erosion of accumulated stores; early fall – build a population of young bees for wintering; late fall – close out brood to conserve stores in early winter.
One last observation that I expect to be unanimously rejected is that the colony adjusts the population to be proportional to stores and hive total volume. Adjustment of population is accomplished by regulation of brood nest volume. This population control can be seen in the relative cluster size going into winter in northerly locations versus my area. Where successful wintering requires three deeps for wintering the early winter cluster is much larger than my area where a story and a half is sufficient. Think about it for a minute. If the colony failed to maintain population in balance with stores what would happen? Overpopulation would be suicidal – too much consumption would lead to starvation. Too little population would lead to slow build up, and the colony would fail to meet reproduction requirements in a timely manner. They need to maintain a supply of foragers to take advantage of any field sources that become available. Additionally, all the population need to be on the inside before the advent of severe cold weather.
I suspect the skill for population control is a result of their natural habitat. All tree hollows are not the same volume. The bees are adapted to using the total volume and regulating population and stores in proportion. Enough of my personal opinions! Let’s push on.
This season (08) two swarms were collected from hives checkerboarded in early Mar. These hives were sold to a beginning beekeeper in the winter, and I showed him how to open up the overhead honey for swarm prevention on March 1. He failed to meet the second requirement of swarm prevention by not maintaining space at the top for colonies to grow into. Expecting them to swarm, three trips were made to that location on prime swarm issue days to see what happened. Two oversized swarms were collected and relocated closer to home. It’s what happened to the two swarms in the establishment process that is relevant to the subject of this submittal. Not ever having collected a swarm from a checkerboarded hive, I followed their establishment progress with interest.
Both these swarms were large – a product of the increased brood volume of my management approach. Housed on foundation, they covered more than four frames. A normal feral swarm covers 2 to 3. Geared for establishment, with a good flow on, they were not fed. At the end of a month, both had nearly filled their deep with drawn comb. At that one-month inspection, both colonies showed queen failure with a spotty brood pattern. They also showed they were on top of the problem – both had started supersedure cells. While it is normal for a natural swarm to supersede the old queen later in the establishment process as a precautionary measure, this was little early in the process. And both was identical in cause and effect. This caused the old man to wonder if perhaps the increased brood volume of my system pushed the queen to her lifetime limit of egg production. Two other observations came to mind. In other seasons, occasionally a colony started supersedure well before the others, and generally, slower or weaker colonies did not start supersedure as soon as the strongest. Collectively these observations suggest that the total lifetime egg production of the queen may be approached in one season when checkerboarded. Time to do the arithmetic.
First order of business – get an accurate count of cells per frame. I was surprised at the numbers of cells imprinted on an installed sheet of foundation. I use deeps for the basic wintering brood nest and shallows for the spring brood nest expansion. The count yields slightly more than 3500 cells per side or 7000 cells per deep frame. A shallow frame is almost exactly half that. Wow!
Before we get too far into this, let me quote Dr. Farrar’s reference to queen laying rates. He was an astute investigator, and I’m inclined to trust his judgment.
“Good queens seldom lay more than 1,600 eggs per day” (Part I)
“A prolific queen will require the equivalent of from 12 to 18 standard combs, depending upon the amount of honey and pollen in the hive even though theoretically all of her brood could be contained in 5 to 6 combs.” (Part II)
Elsewhere in his 8 part article he used 24 days as a brood cycle. This allows a few days for cell cleaning after emergence and preparation of the cell for eggs to start the next cycle. We’ll use his number for a brood cycle. Note that with the stroke of a pen, he debunked the notion that a single deep hive body is sufficient room for a queen to lay at her max rates.
If we integrate quote I and II above, we could conclude that most of his brood nest is contained in two deeps. He refers to his management system as an “unrestricted” brood nest. He maintains a larger brood nest by periodic hive body reversal to offset the natural brood nest reduction of swarm preps.
I also refer to the brood nest of checkerboarded colonies as unrestricted, but it is quite different. When checkerboarded prior to the swarm prep period the colony does not start the brood nest reduction of swarm preps. They continue brood nest expansion through the swarm prep period. My target brood volume is 2 ½ deeps of brood, but I often see more than the equivalent (in shallows) of three deeps of brood. That is a huge difference in population to work the flow. As Dr. Farrar points out, the key to maximizing production is colony population.
Back to the numbers game: To avoid boring you with an overdose of calculations, let me try to summarize. The numbers provided by Dr. Farrar are supported by my three-dollar calculator and observations of the brood nest size in double deeps. With 7000 cells per frame (wall to wall) it would take 4.3 + days for the queen laying 1600 eggs per day to fill a frame. With 24 days to make the circuit, she could recycle brood in roughly 5 ½ frames at that rate. It is important to keep in mind that the brood nest expansion into overhead honey in the spring is dome shaped. The upper deep brood volume seldom exceeds half the available cells of the brood frames. When periodically reversed the natural brood nest reduction is offset during the swarm prep period and that technique does increase population for the flow. It also reduces swarming by not letting the brood nest decrease to the point of starting swarm cells. The brood volume is maintained at about a deep and a half through the reversal period, but contracts sharply after the last reversal. Dr. Farrar reversed hive bodies into the main flow to insure population through the flow.
The checkerboarded colony not only has more brood volume during the buildup but they are also slow to reduce the brood volume into the main flow. They seem to enjoy operating with a position of strength and accumulate much more honey than they need.
But this is about queen laying rates. I’m not an investigating scientist and have not accumulated definitive data on brood volumes. As noted above brood volumes of the equivalent of three hive bodies are seen routinely. Using a nine frame brood chamber, normally, the five center frames are used for brood. Another factor to consider is that as the brood nest grows upward through shallow supers the expansion dome is often in the top shallow supers. Intermediate shallows are often wall to wall shallow frames of brood in five frames. Five shallow frames of wall to wall brood is approximately 3500×5 or 17,500. It would take a queen laying at a rate of 1600 eggs per day almost 11 days to recycle brood in that single shallow. She could recycle brood in two such shallows in the circuit time, but what about the other shallows and the basic deep? My target brood volume of 2 ½ deeps translates to a deep and 3 shallows. Often the brood volume is more than that – up to 2 shallows more (a deep and 5 shallows.) Recycling that volume at 1600 eggs per day is not possible.
Call me a liar if it suits your purposes, but I am certain that I have seen brood volumes that would require a queen to lay at least 3000 eggs per day. Inspection of those oversized brood nests indicated that the queen was keeping up with the demand. Perhaps the capability of the queen to exceed normal requirements is just another safety margin as are built into all survival traits of our bees.
If I were going to investigate maximum queen laying rates, I would check the rates of the new supersedure queen. Depending on how early in the supersedure process the old queen is terminated, substantial empty brood cells accumulate. The colony superseding will hold essentially the whole brood nest open pending the maturing of the supersedure queen to egg laying capability. The supersedure queen, playing catch up, can exceed the 3000 rate. The enterprising post-grad student could pick up this gauntlet and slap me about the head and shoulders with it. If he proved my observations are valid, he could make a name for himself.
With the normal ups and downs of seasonal brood volumes, it is difficult to estimate the total eggs laid in one season, or the difference between standard management and nectar management.
At this point, I’ll withhold judgment on whether or not early supersedure of the two swarms described above was caused by the queens running out of lifetime capacity. I have no way to evaluate the amount of sperm stored by the well-mated queen. Seems I’ve seen a million plus in the literature. A rough count of local brood volume for the season, when checkerboarded, doesn’t reach those numbers, but I’m not dismissing it as a possibility.
For nine months of the year the CBed colony brood volumes are similar to the reversed double deep. The extreme differences are primarily seen during the swarm prep through early main flow. That period spans the prime swarm issue season. (See the ’03 series that explains that period). CBing accelerates brood nest expansion and induces continued expansion until three weeks prior to “main flow”. But even twice the brood volume at the peak doesn’t seem like a big impact on the season-long total. That certainly would not explain the longevity of the queens with standard management.
Supersedure, when CBed, does occur in that peak demand period, or shortly thereafter. It is possible that the colony decision makers perceive the strain on the queen in keeping up with demand and opt to supersede. We’ll leave it to the experts to determine if they ever get around to caring about honey production again.
This submittal shouldn’t be construed as an attack on the concepts of Dr. Farrar. He was on our side, and his investigations and recommendations were oriented to increasing honey production. In retrospect, I think he shaped my thinking on honey production. I highly recommend his 8 part discussion of the details for anyone interested in making more production per colony. American Bee Journal republished his 1973 series starting with the January 1993 issue – Title: Productive Management of Honey – Bee Colonies.
Walt Wright
Box 10
Elkton, Tn. 38455
615-468-2059
