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Inside a mason bee nest

Frank M.  contacted me recently about his findings at his yearly mason bee workshop.  A most interesting series of photos- with permission.

“This photo shows some extraordinary wiry frass, even more wiry than the material that I showed you last year from the 2010 harvest.  Any ideas?  There is also some fluffy stuff in the same chamber and the one next to it, similar to the material in one of the images on one of your blogs.”
This beautifully constructed chamber inside a routered piece of wood, has concave mud walls.  It normally contains one masn bee cocoon, but something has entered it.  The chamber contains frass- or insect fecal material.  According to Bosch and Kemp (2009)  wiry frass is likely produced by one of two insects found in masn bee nesting tunnels.  One is the cuckoo bee.  If there is a cocoon amongst the mass of frass- then it would be the cuckoo bee.  If there is no cocoon- it is most likely the spider beetle.  It is about 2-3mm long with 4 white patches on its back and long attennae.  Both insects eat and destroy the mason bee larvae and its food.  They both invade the chamber when it is pretty close to being sealed by the bee.

There have been half a dozen reports of cotton fluff inside the nesting tunnels.  Here is one I found myself.  Most of the fluff is just that, but two cocoon type structures were found in the center row.  If someone knows what this is please let us know.

A nesting tray with 6 routered channels containing mason bee cocoons,
and cotton type fluff in two of the channels.  

Here I have lifted some of the fluff out to show how it neatly fits into the channel.

Two cocoons were found inside this fluffy material.
You can see the end cap directly above where the cocoon is held in the photo.
 The end cap is made of several layers of mud and is thicker than the usual mason bee end cap.

For comparison, this appears like a spider web,
 which either contains young spiders or an adult spider.

 When I find resin bees inside nesting tunnels, I remove any mason bee cocoons , remove mason bee debris out of tunnels with a tooth brush, close up the nest and set out side ready for next year.

Two delicately placed resin walls.  No bees were in these cells.

Resin bee pupae within compartments made of resin.

Last year’s resin bees emerged during summer months
when resin softened up with the heat.   

Here the beneficial wasp is inside a routered tray nesting tunnel,
 securely within its mud vestibule.
TODO:  Remove any mason bee cocoons with a Scoop and  remove
debris with an old toothbrush.  Then replace lid over beneficial wasps and  set
outside ready for next year.

Last week a mason bee keeper asked me to look at these two photos and give them feedback on the insects inside the nesting tunnels.  Every nesting tunnel tells a story!

These are beneficial wasp pupae encased in a very delicate cover.
  These beneficial wasps provision their nests with either spiders,
 aphids or moth larvae.  Sometimes if an egg does not
 develop the larvae food remains in the cell.  

This is a picture of cocoons harvested from nesting tunnels.
The dark brown, still with mud attached, is from the early
 spring mason bee Osmia lignaria.  The reddish cocoon with its bright
 orange fecal material and masticated leaf plugs are probably
 Osmia californica.  Osmia californica is active towards the end of the
 early spring mason bee activity.
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.

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