Hive Inspection 20140424

I went into my new, growing split this afternoon.  Things looked to be in good shape although I plan a little more detailed examination shortly (see below).  There were no queen cells, a few drone cells, lots of honey (probably from the sugar water I've been feeding), and some pollen (I'm not experienced enough to tell if it was a lot, sufficient, or what).  The pollen patty strips I put on one week earlier were all gone.

As I took out and examined each frame I took a picture of each face with a digital camera.  I was able to identify and estimate how much capped brood was on each face.  I used Paint to draw a rectangle that I estimated to more-or-less identify the capped brood.  Paint gives the dimensions of the rectangle in pixels.  By measuring the height of the frame (5.625 inches) in pixels I could convert pixels squared to inches squared.  As there are 25 cells per square inch another multiplication gives the number of cells (hence, bees).  See the image below.

All told there were 14 faces containing at least some capped brood.  The smallest patch was about 6 square inches (150 cells) and the largest was 63 square inches (1,575 cells).  All together there were 482 square inches which computes to 12,050 cells of capped brood.  As capped brood exists for 12 days we can estimate the average number of eggs laid starting 21 days prior and extending to 9 days prior was 1,000 per day.An estimate of the total brood can be made by figuring 3x1,000 eggs and 6x1,000 larvae for a total of 21,000 covering 840 square inches or 6 1/2 equivalent frames at 60% coverage.

Is this a good, bad or indifferent value?  I don't know.  Only by comparing to other queens/hives or other times (this was a new split originally and I think the queen may have been hampered by insufficient space as the workers drew out more comb).  But it is a real number (within the bounds of the estimation technique).  Based on the analysis in the previous post, this hive could ultimately level off at some 40,000 bees.

Bees by the Numbers

Bee Arithmetic

A medium frame of 4.9 mm/cell comb has about 30 rows of 88 cells for a total of 2,640 on each face. The area of the face is about 65,800 sq mm. A worker bee occupies about 88 sq mm.

Ergo:

• A medium frame completely covered with bees would have some 750 bees on each face, total 1,500 bees.
• A queen might be expected to lay in about 2,000 cells (80%) in each face.

Consider that ALL of the bees will be in the hive overnight. The 'carrying capacity' of the hive will be 1,500 per frame times the number of frames. Each box of an 8-frame medium super can hold 12,000 bees. This has nothing to do with how much room the queen needs for laying or how much is needed for stores, it is merely the 'parking space' needed to keep all the bees out of the night air. One must plan the number of boxes based upon how many bees are expected/hoped for. Too little and the queen may stop laying while waiting for capped brood to be evacuated and cleaned up.

How many bees are ultimately in the hive depend crucially on how many eggs the queen lays per day. Death rates, will ultimately limit the final population as bees start dying at about the same rate they are being born (if the queen continues at the same rate – if she declines, the overall population will also decline).

We can model this with some basic assumptions:

• On the day the queen starts laying in earnest there will be some initial population, perhaps the survivors of winter and some limited brood that will hatch out over the next 21 days. We will be interested in the results 40 days out from when we start counting and these bees should all be dead by then.
• We assume the queen starts (or is) laying at a more-or-less constant rate of X per day.
• For the first 21 days there will be no 'new' bees – hive population will be more-or-less steady.
• Starting on day 22 there will be X 'new' bees every day – the population will start to climb.
• These newly hatched bees will spend about 10 days in the hive before venturing out to the risky business of foraging for nectar and pollen. At the end of the first 10 days the hive population will have increased by 10 times X.
• So, on day 11 after the first 'new' bees emerge X bees will become foragers and these bees can be expected to live for 30 more days. In the 30 days before the first foragers start dying (also at the rate of X per day) the hive population will add 30 times X more bees. From that time on the number of foragers that will die each day will be X and the total population will have leveled off.
• The leveling off point is 10X + 30X = 40X.
  
  

So, we see that X marks the spot! Or, at least, is the key figure in hive strength – but we knew that all along. Now we have some understanding of how to analyze any given hive and, maybe, what to do about it.

We've heard folks talk about queens that lay 2,000 or more eggs per day, of 'strong' hives, of hives 'full of bees.' From above we can see that such a wonderful queen would need at least 6 medium boxes to hold every one of her children in rainy weather. I would be suspicious of any claim that a 2,000 egg per day lady is happy in a 3-box setup. Likewise, it should be easy to quantify what 'strong' and 'full of bees' mean by simply counting frames covered with bees and estimating the percentage coverage of those not completely teeming with bees.

As to what to do about this new found knowledge of the state of one's hives it appears that the danger would be to hold a good queen back by not giving her and her babies enough room. We can estimate how well the queen is doing by counting frames of brood. We don't need to search for eggs and young larvae, it is enough to count the sealed brood because, once the first 21 days are past, there will be 12X cells of capped brood at all times. Assuming a 'full' frame is some 2,000 cells a 2,000 eggs per day lady will have 6 frames (both sides) of sealed brood. (If you saw 6 frames of capped brood early on before the first 30 days have past, would you prepare more boxes – the possible population could hit 80,000 bees? Hmmm, that also implies that there were some 15,000 bees in there to cover 10 ½ frames of brood to keep them warm.) Needless to say(?), only 3 frames would indicate a 1,000 eggs per day queen, etc.

Now all this last assumes that the queen has room to lay, the nurse bees have enough food to feed the larvae, there are enough bees to cover the brood to keep it warm in cool weather, etc. The first two are in the control of the beekeeper, the third is why a strong hive coming out of winter is so important (also explains how moving bees from a weak hive to an other-wise stronger hive makes sense).

Actually, there is another variable under control of the beekeeper that might advantageous – frame spacing. Michael Bush (http://www.bushfarms.com/beesframewidth.htm) reports that if the faces of two opposing brood combs will only allow one layer of bees, that number of bees will be sufficient to keep the brood warm, take care of the larvae, etc. That means a given number of bees can cover and care for twice as much brood as when there are bees on both faces of the brood. If the limitation on build up is the queen's capacity or lack of comb, the bees freed up can work on making more comb (or go out and forage).

BUT, hearkening back to the start of this post, there is still a need for 'roosting' surfaces to accommodate everyone at night or on rainy days. Squeezing the frames together cuts that 'roosting' space in half and the beekeeper will have to compensate somewhere. Perhaps the close spacing would only be used when the hive is not so populous (early Spring?) and would be relaxed as the numbers build up. Or, maybe extra supers might be provided. I'm thinking close spacing would be very useful with new splits or packages when brood rearing and comb making are paramount and there are no dangers of overcrowding.

Please comment if you have something to add.

More on Swarm Traps

Cool, rainy weather gives more time in the shop which I have used to continue making boxes, most recently 5-frame boxes to use as nucs or I want to experiment with building up some 5-frame colonies.  But I can't give up the idea of catching swarms this Spring and these boxes won't be needed for many weeks.  In an earlier post I showed how I used some nuc boxes to make up a swarm trap so I thought, why not do it again.

I didn't want to make a big ol' hole in my nice new boxes, though, so I thought why not make the hole in the bottom?  I doubt any scout bees would care where the hole is as long as it smells good (lemon grass oil).  So I found some pieces of siding material in my scrap pile to make tops and bottoms and used the cabinet latches described in the previous post to attach two nuc boxes to make a two story 5-frame trap.  The picture below is worth a thousand words.

More Bee Arithmetic

I want to follow up on the previous post on Bee Demographics, trying to reach a better understanding of what's going on in the hive and, maybe, get some management insight.

Starting off with some assumptions:
1) the bees are well fed and have plenty of room.  Both of these are under the control of the beekeeper.
2) the queen is capable of laying 2,000 eggs a day (and will do so if the above condition is met).  We will discuss how the beekeeper can verify or re-estimate this number below.

After Spring build up and the queen has been laying for 21 consecutive days, we can see that the brood will consist of:

3x2,000 = 6,000 eggs
6x2,000 = 12,000 larvae
12x2,000 = 24,000 pupae (capped brood)

The eggs and capped brood need only to be kept warm by the workers.  The 12,000 larvae need to be fed and 2,000 need to be capped every day.  This is the maximum work load on the workers.

A medium frame of 4.9 mm cells contains about 6,500 cells (both sides).  Therefore, a queen laying 2,000 eggs per day requires 7 FULL frames to keep her busy.  Once this is reached there will be 2,000 empty cells vacated by emerging workers every day to make room for the 2,000 new eggs to be laid.  The actual location of the total brood may migrate but the total area should stay the same.  In practice the queen probably won't fill any given frame edge-to-edge because the workers tend to put honey and pollen in the corners.  The beekeeper will need to estimate the percentage of brood (in any stage) in each frame to estimate how well the queen is performing.  Thus, it will take 14 frames with 50% coverage, 11 frames with 70% coverage, etc for a queen performing at 2,000 eggs per day.  More is better, less is worrisome.

In my readings, I've seen advice to give a weaker hive (ie, a hive with significantly less brood) a frame or two of brood from a strong hive (ie, one with a queen that lays 2,000 eggs or more per day).  I've also read advice to do the opposite but haven't seen a reason why (except, of course, some master found it worked better!).  This analysis tells me what appears to be a better approach.  If a colony with a weak queen is give a couple frames of brood there will be a temporary burst of new bees in the hive, but afterwards the amount of brood will settle back down to the previous level which is solely determined by how many eggs the queen can lay per day (always keeping condition 1 above satisfied).

Say you've got a hive where the amount of brood indicates a queen with only 1,000 eggs per day capacity.  In 30 days she will produce 30,000 new workers.  Sounds good, but compare it to 60,000 new workers per month!  Nipping her and allowing the workers to make a new queen will cost you a month of new bees (30,000) but a 2,000/day queen will make that up in a month and then go on building even faster.  If you can get a ripe queen cell (or mated, ready-to-lay queen) you can put the drawn comb an other resources in that weak hive to use even faster. (As I write this - April 2014 - I see mated queens offered for $25).

Comments always welcome.

Bee Demographics

I've been reading a lot and I keep coming across various numbers that must be "magic."  For example, I read that 8 frames of brood seems to be a happy number for a strong hive, more are better and fewer often need to be strengthened.  I also see various estimates of how many eggs a queen can lay in a day and 2,000 seems to indicate a "good" queen, more a "great" queen and fewer a "so-so" or even "bad" one.  With all this are the truly magic numbers of 3 days in the egg, 6 days as a larva and 12 days as a pupa before a new worker bee emerges so I did some calculations that, to me anyway, are enlightening.

Let's consider a queen who lays 2,000 eggs a day and has plenty of room to do so.  On day 1 she will lay 2,000 eggs and so on.  On day 4 there will be 2,000 young larvae to feed, on day 5 there will be 4,000 larvae to feed and so on up to day 9 when there will be 12,000 larvae to feed.  I don't know how many larvae a nurse bee can feed per day but I would think only a moderately sized population could handle this load.  But on day 9 2,000 larvae will be capped to pupate so from there on there will be only the same 12,000 growing larvae to care for.

Our queen will continue laying 2,000 eggs a day (if she has room) and by day 21 she will have laid some 42,000 eggs.  On that day 2,000 new bees will emerge thereby freeing up 2,000 cells for the queen to lay in again.  So, allowing from some down time to clean up these cells for the queen we can estimate that a queen only needs some, say, 45,000 cells to keep busy laying all her life.  We can also see that this amount of brood in the hive, once built up, will stay about the same as long as she is laying at that rate.

I estimate a medium frame of 4.9 mm cells to contain some 6,000 cells (both sides).  A deep would have maybe 10,000 cells.  If the cells are the "standard" 5.4 mm there would be only about 80% of these numbers (5,000 and 8,000, respectively).  Given that brood frames often have honey and pollen stored in the corners so not all of these numbers will be occupied by brood and assuming 70% would be thus be used, we see that 8 deep frames of the 5.4 mm cells would contain some 45,000 available cells  and we have linked the ideas that 8 frames of brood and a queen laying 2,000 eggs a day are a happy combination.

I don't know it the old-timers made such a calculation or even if it makes much difference (their experiences, which we can take advantage of, that a queen that produces 8 frames of brood is good gives one a measure to evaluate hives).  But for me (and maybe others) who use the smaller cells and medium frames we can guess that the comparable measure is 45,000 divided by 4.200 or 11 frames.  Seems reasonable.

As far as managing with this idea, we can see that starting from a 5-frame nuc that we will need to double or triple those 5 frames as soon as possible.  It also suggests (to me, anyway) that the idea of splitting into 2-brood nucs might ought to be upped to 3-brood nucs.

Hopefully, some food for thought.  Comments welcome.

Adding another box and feeder

Yesterday there was a brief warm, partly sunny period between waves of thunderstorms (2 1/2 inch rain total) so I wanted to peek in the new hive and check on the ladies and put a hive top feeder on for them.  When I built my boxes earlier this Spring I sorta made a mistake in that I ended up with a 9-frame size instead of the 8-frame I thought I was making.  Oh well, we'll just call it an experiment!  But, I recieved 9 full frames with the bees so I thought I would start a new box with foundation to give them room to expand.  I also made up some dummy frames (a top bar with a 1x board the size of a drawn frame) to cut down to an 8-frame size.  I will put the dummy in the outside position and that will be the first one I take out whenever I go into the hive.

I decided to pull two of the frames from the bottom and put them in the middle of the new super with 6 frames of foundation and the dummy frame on the outside.  I didn't want to spend a lot of time this first look into the hive so I didn't make a thorough search for the queen, I just gave a quick glance on both sides of each frame and moved on.  I did look for honey, pollen and brood though.  There seemed to be quite a bit of honey but I didn't see much, if any, pollen.  And I was somewhat disappointed by how much brood I saw.  There was capped brood and I saw some fairly large larvae but couldn't be sure I saw eggs.  The larvae and capped brood were undoubtedly before the split 4 days before when we definitely saw the queen.

I put a pollen patty on top of the bottom box, put the new super above that and the hive-top feeder with about 1/2 gallon 1:1 sugar syrup on top of that and closed up the hive.  BTW, I used very little smoke on the entrance and none from then on (of course, the smoker went out!) and the bees were very calm.  I think I could have easily worked them without gloves.  As of dusk last night there was no sign that the bees had discovered the sugar water.  The feeder will not let the bees escape so I can just lift the cover and peek without really disturbing them - although the light that gets into the hive draws some attention, probably because they suspect and invasion.

Given what I think was a low supply of pollen maybe the small amount of brood is understandable.  Hopefully, the pollen patty will  remedy that situation and they will take to rearing a lot more brood very soon (there were quite a lot of bees who could do the job).  We'll see when I peek in again on some warm day (it WILL get warm someday, won't it?).