A comment on this blog asked for more pictures on candling cocoons. 

Just today I candled 4000 cocoons.  It seems like an awful lot, but when they are in  petri dishes it is easy to do candle them- about 30 mins or so.  I did see some duds that are of some interest.  I call anything that is not a fully developed bee a ‘dud’.  The percent ‘duds’ in this batch was 2.5%.  Anything under 5% is excellent.  But even with 107 duds there are some interesting ones.  Few had fully developed parasitic wasps- ready to emerge in spring.  Others were bee larvae that had not completed development into an adult. In the next day or so I will take some photos and put them on this blog.

I was teaching a group of people about candling the other day.  It is a straight forward procedure but the conditions have to be right.  The room that you do the candling in has to be completely dark- a bathroom without a window for example.  Any extra light besides the flashlight is too much light and you cannot candle the cocoons.

5 replies on “Candling cocoons

  • borntobegreen

    I've candled bantam chicken eggs many years ago to see if they are fertile, but never heard of this.
    Very interesting. Can you tell me what is a petri dish?
    I've had a lot of duds the last couple of years. Disappointing and this year's weather has wreaked havoc with wildlife.

  • Nora Boekhout

    Hello! I have candled pet bird eggs before and will now try it out on our Mason bee cocoons this fall. My question is, what does a cocoon with parasitic wasps look like? Is it really distinctive from a bee shape in the cocoon? Thanks! 🙂 Nora

    • Margriet

      yes it is very distinctive. When cocoon is filled with wasps- you can see individual wasps – usually up to 10 per cocoon. The bee inside a cocoon is curled up in a fetal position and looks very different from the parasitized ones.

    • margriet dogterom

      After candling cocoons need to be stored in a safe place. Please refer to our Nov newsletter. The newsletter will be published shortly by mid November. I will be writing on the advantages and disadvantages of either storing them outside in a rodent proof container or keeping them refrigerated.


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