From summer to early winter place mason bee homes inside a net bag. This will prevent your mason bees from being parasitized while they are inside their cocoons over the winter.
Tiny parasitic wasp of mason bees
Can you verify that this picture is a Parasitic Wasp (or not)?
Wild Bird Chalet
705 Kentucky Street
Bellingham, WA 98225
Hi Valerie, Thanks for sharing this photo with us and our friends. Yes this tiny little wasp is a parasitic wasp of mason bees (and other insects). You can see from the size of the cocoon in the background how tiny this critter really is! At the moment that this picture was taken, this wasp was listening for bee movement inside the cocoon ( it hears with its antennae). Only live bees are parasitized!! Great picture Valerie.
It July 8/12. Is it too early to put a cloth bag over mason bee boxes to keep out predators?
We are in Comox, Vancouver Island. – Margaret
Yes it is time, BUT some bees may still be flying!
I just visited 2 sites today and in both yurt field structures, bees were still flying in and out of their nests.
Tomorrow, I will go back to these two sites, and remove all the release shelters- to avoid additional parasitic wasps that might still need to emerge.
I will also bring a battery powered bug killer- like a small tennis racket with an electric battery driven electric zapper. This should get rid of most of the active parasitic wasps. In another 2 weeks, I will check again, and all, if not most mason bees will have quit by then. At this time I will place a net bag around each nest to prevent parasitization by the little wasps.
It is quite amazing to see these critters still flying into mid July.-Margriet
This is my yurt field structure in Bellingham WA. It is fully laden with highrises and a lot of the tunnel are filled by mason bees. Today we removed all the release shelters. Quite a few bees were flying in and out of the nests…more in a subsequent blog.
From Norm Z.
Can you ID these insects for me? If so what are it’s nesting habits? Thanks
Here they are-lovely photos- any body know what species these wasps are? Probably parasitic types, since they are hanging around the mason bee nests.-Margriet
When I have large numbers of cocoons, I often use trays. There are about 2000 cocoons on this tray. One tray is turned over to act as a lid. Trays are offset by 1/4″ so that emerged bees can exit. Duct tape or strong rubber bands are used to keep trays in position.
Using 1×1 sticks and set between a couple of highrises, a structure is created to hold trays at the upper level of the yurt, but not under the center hole of the roof.
|Base tray holds about 2000 cocoons
|Two trays are held in place with duct tape.
|Two trays offset to create a 1/4″ gap.
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.