Predators of Mason Bees

Hi Margriet,

I took the images of the Quicklock trays in the Highrise that have popped open.
As you can see there are a few empty holes now that previously had been full. It must be the chickadee as you suggested.

Do you think it is too risky for me to try to tape it tight again? I dont want to squish them but they are completely exposed now.

Your bee-loving friend, Eve

Hi Eve, I would not try and tape the nesting trays at this stage.  When they are done flying turn the trays so they are facing inwards- then the chickadees can’t get at the larvae.
Margriet

Quicklock Trays in a HIghrise showing tape has loosened around nesting trays.

Brilliant!

That’s why you have a Phd  and I don’t. 🙂

Hello Margriet.
This is my second year with a mason bee nest. When I cracked
open my corn plastic stack to clean my nest last year I was surprised to find two
of the tunnels occupied by spiders.
I had at least 25 cocoons hatch this spring. I went out o check on the house
on Tuesday and noticed webs around the house. On closer inspection, at least
three tunnels had fine webs over the openings.
I assume the spiders prey on the bees. Am I correct? And if so, how do I get
rid of them without disturbing the entire corn plastic bee stack?  Thanks,  Kevin K
The only way I know is to catch and remove them from the site.  This would be quite difficult I think. 
 I have seen a jumping spider catch a mason bee!  So bees beware!  Dr Margriet

Check out your mason bee homes every now and then, and make sure you do not have a line of ants crawling towards the bees’ nests.  A good way of getting rid of them is to first remove most of the ants bysquashing them, and then have a water spary and then drip at the location where ants are crawling up the structure.  When the ground is wet, ants are discouraged from going in the direction of moist soil.

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.