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  1. #1
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    Default Calculating Swarming dates

    In another thread BernhardHeuvel posted the following:


    Quote Originally Posted by BernhardHeuvel View Post
    To visualize what I have wrote I put the following table. This is this year's Spring temperatures and the connected egg laying rate put together with starting parameters from a rather small colony. Starting parameters are estimated by inspection in February.

    We got a late cold snap this year, which stopped the brood increase and hive development for some weeks.



    Once the brood amount reaches 18,000 brood cells (which is considered the minimum amount of brood necessary about 40 days before the first flow for a productive colony) and the ratio bees and brood is 1:2 (or 200 %) the colony starts drone raising. It is pretty astonishing to actually be able to calculate from outside maximum temperatures the date when they start drone raising. But it works. Just track the temperatures and with some forecast data (which are not really reliable, especially in Spring...but a week or two in advance) you can calculate and predict the hive development. (To a certain degree of course. At the end it is just a calculation, not the reality.)

    When the bee:brood-ration drops below 150 % after the first increase of the broodnest, the bees start definite swarm preparation, means they build swarm cells.

    I still do not know, why that is, but hopefully others join in and verify the calculations by their own observations and monitoring. As said above I think it is the brood that releases hormons and by the ratio bee:brood the overall nest scent/smell differs.

    Maybe this sort of insight, if it can be verified, delivers the background for why checkerboarding works - or helps to localizing the method by adjusting the system from the daily maximum temperatures.

    I have never seen this before and stated that I didn't think there is a direct correlation between egg laying and outside highest temperatures.

    But I do have a theory that Swarming happens when the ratio of Nurse bees to Open brood gets to a point where there too many Nurse bees for the available Open brood (larvae - days 3 to 8).

    Looking at this data actually proved the point!

    In Calculating the Open Brood I used the following (5/1): 26006-15533-1083-883-1083=7424


    Notice the number of Nurse bees start to exceed Open brood from the 3rd May:

    DATE. * NURSE BEES. * OPEN BROOD.
    5/01. * 4899. * 7424.
    5/02. * 5572. * 7463.
    5/03. * 6346. * 6384
    5/04. * 7305. * 4935.
    5/05. * 8994. * 4934.
    5/06. * 10637. * 6072.
    5/07. * 12043. * 6606.
    5/08. * 13229. * 6776.
    5/09. * 14696. * 7216.
    5/10. * 15807. * 8567.

    Swarm Cells
    5/13. * 17303. * 8538.
    5/14. * 18092. * 8078.


    I believe Swarming is related to the following ratio:

    Nurse bees : Open brood (brood between 3-8 days old)

    When the numbers of Open brood get too low, or the numbers of Nurse bees gets to high, there are too many nurse bees to feed brood. Hormone levels in the Nurse bees change due to not feeding brood. Brood gets overfed with royal jelly. The queen get harassed more, and lays less. All conditions conducive to swarming.
    Last edited by MattDavey; 10-02-2013 at 06:09 AM.

  2. #2
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    Default Re: Calculating Swarming dates

    He also replied with this.

    Quote Originally Posted by BernhardHeuvel View Post
    Well, as I wrote in my post above. It is a model that I use to forecast what is going on and it works pretty well for me. Means, I find in the hives what I forecast. Not a 100 % the same, but as you said: nothing is 100 % dealing with animals. Especially with bees.


    Well, a very well known bee scientist, Josef Bretschko found out that correlation. He studied it in detail for decades and even wrote in a book about it. Two other bee scientists, Bergmann&Bergmann continued his work and verfied what he has found in their own studies. They even were able to develop a formula, which is the one I use in my calculations.


    The formula is: egg laying per day y = x * 22.8295 1.4254 high
    Where x = is the daily maximum temperature.


    Bergmann&Bergmann also wrote a chapter or two in their book. With all the tables and results. The studies were done with Carnolian bees, but Bergmann&Bergmann indicated, that the correlation is true for other bees, too. As I find with my Buckfasts, this can be confirmed.


    I just can invite you to look closer into it by your own observations. Write down the daily maximum temperatures and calculate from it, check with reality. I was surprised myself, since I am a bit sceptical a person.

  3. #3
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    Default Re: Calculating Swarming dates

    Wow.... very time consuming data collection.

    All I know is that the truck and gear is ready for swarm calls by May 1st.

  4. #4
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    Default Re: Calculating Swarming dates

    On a related note. In one of the old bee masters books that Michael Bush promotes (perhaps Jay Smith?) the author says that swarm cells will be broken down by the bees if you add open brood to a hive that has started them. Taking the time to understand this is valuable. The difficulty I encountered as a new beekeeper was that the bees population explodes so quickly in the spring.
    Matt thanks - food for thought.

  5. #5

  6. #6
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    Default Re: Calculating Swarming dates

    Thanks Bernhardt.

    Fantastic work, great graphs too.

  7. #7

    Default Re: Calculating Swarming dates

    Quote Originally Posted by David LaFerney View Post
    I've never seen it quantified like that though. *I assume that you feel that is accurate?
    Well, it has been found by a very well known (at least in German speaking countries) bee scientist, Josef Bretschko, who has had a good reputation among beekeepers here. His followers, Bergmann&Bergmann verified it and put up the formula. I just put up a spreadsheet and forecasted the development of the hives with the help of the weather forecast (which of course is somewhat limited).

    From what I observed, the calculations really helps understanding what is going on in the hives and what is coming next. It really helps to forecast the next two weeks and with some local climate data, the next months.

    Of course there are presumptions, which are: queen has enough comb to lay eggs in, bees have enough to feed on (pollen and nectar), no robbing, queen is OK and so on. So if you really care for your bees and look after the above beekeeping basics, you really can forecast what is going on. At least I did.

    The authors Bretschko, Bergmann&Bergmann used the calculation for Spring development only. But I found out, that this is true all summer and autumn, too. But in summer the incoming nectar and pollen and the swarming fever reduces the egg laying significantly. Of course. And mathematically it has, because otherwise the colony would explode in numbers.


    Quote Originally Posted by David LaFerney View Post
    Aside from swarming issues this data should give some insight about what is going on it the hives
    Exactly. I rarely use it for swarm prevention, because my swarm prevention is the early removal of the old queen which is very effective. But I use the calculation to decide when to super the first time. I just wait until the numbers of capped brood cells is about one box of comb worth. One comb of brood produces four combs of bees. And with a box full of capped bees, the emerging bees will readily take the super given.

    The calculations also allows for decisions when to make splits or when to combine. What is the latest date to make splits - and so on. When to treat: I look for lots of open brood at day 8, little capped brood. So mites most probably are outside the cells in great numbers where I can reach them with the treatments.

    It also helps identifying when something's wrong. If you calculate a certain state of the colony and it can't be found in reality, I look for what is wrong with the colony.

    I don't think the spreadsheet or formula will revolutionize beekeeping. Since if you have a bigger number of hives, you simply compare between the hives to find failing colonies. Or you simply have a look into the hives what is going on. Experience in beekeeping over a long time also greatly reduces the need for such calculations, because you sort of get a sense what to do, when to do.

    But I find it a great tool to learn with.

    On a bigger scale one probably will understand the deep connection between the colony and the landscape or local climate, which might be max daily temperature as the connecting factor. Bees have to tune their actions to nature, to the landscape somehow. In order to be ready when the flow hits or winter sets in. Watching the temperature and hive development for some time now, I reckon there is something into this thing. Worth looking at closer and maybe you want to jump in and try yourself. The more people observing it, the more eyes, the more results. The only thing to do, is to estimate the number of brood cells and bees in winter right before they start off with brooding. And of course you have to track daily temperatures. I use the data of a weather observatory nearby that is published in the internet. So I put in the data on a weekly basis.

  8. #8
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    Default Re: Calculating Swarming dates

    BernhardHeuvel, this is really interesting!

    One question - what is the amount of capped brood cells equivalent to a full box? Specifically, at what number of capped brood cells do you add a super and what size super?

    Quote Originally Posted by BernhardHeuvel View Post
    I just wait until the numbers of capped brood cells is about one box of comb worth. One comb of brood produces four combs of bees. And with a box full of capped bees, the emerging bees will readily take the super given.
    Last edited by merince; 10-02-2013 at 10:43 AM. Reason: Clarification

  9. #9
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    Default Re: Calculating Swarming dates

    Bernhard,

    I have put my local Temperatures in the spreadsheet since May and I am NOT seeing corresponding results in my hives.

    Here is the spreadsheet with my local temperatures: http://daveybees.wikidot.com/local--...tGippsland.xls

    (It has been a very mild winter here!)

    In the last two months I have seen about a doubling of the Hive populations and the amount of brood. But the calculations don't show that:


    Date`````` | Brood` | Hive | Ratio
    ------------------------------------
    08/15/2013 | 22219 | 37869 | 59%
    10/15/2013 | 31390 | 49026 | 64%


    In fact the calculations suggest if I started with 1000 bees in May I would still be at 49000 bees by now!
    I managed to overwinter a 4 frame Nuc, but they are no where near the same size as my other hives.

    Also, the calculations are suggesting that the Uncapped Brood to Nurse bee ratio has been staying around 1/3. So three times the numbers of Nurse bees to uncapped brood.


    The amount of brood being produced in my hives at the moment seems more to do with the amount of fresh pollen that is coming in (and possibly increasing daylight) rather than temperature.

    I will continue to monitor and plug in the temperatures until we start seeing swarms locally.

  10. #10
    Join Date
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    Default Re: Calculating Swarming dates

    Quote Originally Posted by Mr.Beeman View Post
    Wow.... very time consuming data collection.

    All I know is that the truck and gear is ready for swarm calls by May 1st.
    I'm with you beeman except I have the gear in by March .

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