My name is Dr Margriet Dogterom and am the founder and owner of Beediverse. I write this blog for all who love bees and who want to learn more about these wonderful creatures.
|These cocoons were harvested early October just when weather was getting colder
and water was condensing on the Quicklock nesting trays.
Early enough to avoid fungal growth over cocoons.
|These cocoons were harvested in early Nov, after cold weather had settled in.
A few cocoons were covered in mold. This mold is easily washed off in cold water and a little bleach.
|Quicklock nesting trays with 4 healthy looking cocoons.
Cocoons are covered in feces which is easily washed off in cold water.
|Quicklock trays with healthy cocoons. The brown and black speckles
are bee feces or frass.
Frass is easily washed off in cold water.
|These are different coloured mason bee mud plugs in Quicklock nesting trays.
The black paint is used to help bees orient to their nesting tunnel.
|Small cocoons towards the front of the tunnel are usually males.
The females are in the back of the nesting tunnel and are larger than the male cocoon.
|Sometimes a nesting tunnel consists of a few mud debris.
The female either died before she could finish the nest or she became
disoriented and found another nesting tunnel for nesting.
|Tunnels can be completely full or partly filled.|
Harvesting cocoons from Corn Quicklock trays is fun. You open two pieces of interlocking trays and you see what is inside. Every row tells its own story and often it is a very different from the adjacent nesting tunnel. It is great to see bees at work, but it is very exciting to see what they have produced and to see what other insects are using these nesting tunnels as their home.
This pink larvae has a brown head capsule. It feeds on any detritus and pollen in the tunnel. If left inside over the winter, it can chew through cocoons and destroy your bees. After it has spun its cocoon, it emerges again during the early summer as a moth. I remove these grubs from the nest as I harvest mason bee cocoons.
|The warmth of the room where we harvested the mason bee cocoons warmed up the larvae and made it active. It was travelling around the tray as I photographed it. In the foreground are two mud walls dividing two cells each containing a male bee cocoon. The female cocoon usually fills the space between the walls of the nesting tunnel. Each cocoon is covered in frass and some mites.|
|Here is the larvae spinning its web for its overwintering period.|
For the second year in a row, I have had mason bees nesting in these tiny nesting cavities. These tiny cocoons are similar in colour as Osmia lignaria cocoons, but much smaller in size. I have not seen this small bee fly, so I do not know what they look like nor do I know what time of the year they appear. If you have a piece of corrugated plastic, set a piece in amongst your other nest materials and see what happens.
|Here is the Highrise with nesting trays (without the cedar roof). The gap above the nesting trays is where I insert the folded plastic corrugated material and use it as a wedge to securely hold trays in place.|
|A folded piece of corrugated plastic acts like a wedge above Highrise nesting trays. Most holes in corrugated plastic are used as nesting tunnels by a species of summer mason bee, as can be seen by the presence of mud plugs.The nesting material below the blue corrugated plastic are the Beediverse Quicklock Corn trays. Here the different coloured mud plugs indicates that mason bees use different sites to collect their mud.|
|The spring mason bee cocoon is on the left (with its nesting trays on the far left). The tiny summer mason bee cocoon is on the right.|
|After slicing the nesting tunnel open you can see how the tiny cocoon fits into the tiny nesting tunnel.|
|Closeup of plastic corrugated sheets filled with mud plugs.|
I had to go to my old stomping ground to get this article. In 10 years Simon Fraser University did not seem to have changed much- although I did only go to the library. It is a short ride from my home and so tonight I thought to chase up the 1966 article by Levin. I wondered into the library, walked up to the 5th floor and found The Journal of Kansas Entomological Society. Just like that! I spent a lot of my time in amongst these rows and rows of journals. So it was not surprising that I found the green volumes so quickly. Unfortunately there was no volume number 39. I went to information and a kind gentleman looked to see if the library had it hidden from my view. No, but library did have it in digital format. Perfect! It was fairly simple to search for it on the computer and get it printed out. Parking for 55mins was $3.25! But enough about my adventure.
Here is what Levin had to say about Osmia californica. Levin compares Osmia lignaria with Osmia californica. I will focus on the details of Osmia californica.
-Restricts pollen collection from a few composites
-Does not always overwinter as an adult (lignaria overwinters as an adult)
-About half of 33 overwintering cocoons were prepupae and the remaining half were adult
-Uses a mixture of mud and small amount of leaf tissue (lignaria uses mud only)
-Leaves no vestibule at entrance to nest (lignaria leaves a vestibule)
-Seals last cell with a thicker partition and does not build an end plug
-Buries its egg within the pollen mass (lignaria lays the egg on top of the pollen mass).
I think the most interesting part of this information is that Osmia californica does not always complete their transformation into an adult bee by winter. This means that some bees overwinter as prepupae and complete their development the following spring.