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.
Frank mentioned removing mites with a ‘large stainless steel colander’. The best colander is not just any colander. More about this later, but first, lets back up a little and I will explain my rationale for removing mites.
Getting rid or removing ALL mites from cocoons is difficult. I think the main aim is to remove the majority of mites, so that mason bees have a better chance of producing healthy offspring. Even if all mites are removed from harvested cocoons, there will be the occasional mite covered wild bee that arrives from within the local wood. These mites are spread successfully ensuring mites are always around. The best that anyone can do is to remove the majority of mites from harvested cocoons. This give mason bees a better chance in producing healthy offspring rather then mites.
Washing with water, removes adhering frass and the majority of loose mites. After washing, there are still lots of mites in amongst the threads of the cocoon.
These mites are best removed by friction. I have found the most successful way to remove these mites is to gently roll them over a METAL window screen stapled to a frame. Another way is to gently roll them around colander with a metal screen (NOT PLASTIC, NOT STAINLESS). Plastic and stainless steel do not have the abrasive quality of metal screen.
This can be done in two stages. First wash with the appropriate colander under and in running water. Second, when cocoons are dry, roll them over another screen to get the remaining mites off.
Washing with water, removes all frass and most mites. The removal of frass is an important part of the cleaning process because it allows cocoons to be candled. Successful candling can only be done with clean cocoons. I want to make sure that cocoons parasitized with little wasps don’t end up in the cocoons that I sell or place out for production.
This is a great link to view coloured photos of mason bees pests.
Mites are pests for mason bees. Bees carry them from their old nest to their new nests, and then mites compete for food with the young developing bees. Mostly, if mites get into a cell with a developing bee and its pollen lump, mites will be the end result- not a bee.
Because mites on the surface of cocoons are waiting to be transported to a new nest by the emerging bee, it is imperative to get rid of most, if not all surface mites. Washing will remove the majority or mites. Rolling cocoons over a metal screen will remove the majority of the remaining mites.
Further reading on mite control ______________
A great DVD on How to _________________
Here are a few pictures of
Mites are transported by bees from the old nest to the new.
This is the time when parasitic wasps can produce another generation every week. During the summer months, when temperatures are higher than in spring and fall, these pesky little critters come out of the nest and search for new mason bee cocoons to parasitize. I don’t know how, but these tiny adult wasps can make a tiny pin hole in the tube and crawl out and parasitize more bees.
Every July, when most bee eggs have turned into adult bees inside their cocoons, I gather all nests, set them under a veranda- where the ambient temperature is still warm. I place two Highrises per net-bag (see wasp proof bags on my web site beediverse.com). They sit stacked against the wall of my home until the end of September when harvesting takes place.
I find that net bags are successful and keep out wasp parasites. Percent parasitism is usually not more than 5%. If you have had trouble with these parasites, you will be pleasantly surprised with the outcome.