Tuesday, April 26, 2011

Little horn-faced bees mating!

Last winter I ordered a few cocoons of the little 1/4" long solitary 'Horn Faced' mason bee, (Osmia cornifrons) from Dave at Crownbees.com. Along with my two other species of solitary mason bees cocoons from last summer, I kept them cold all winter and only a few days ago I put them out to emerge as new adults, ready to immediately mate and start pollinating and nesting. (see my other posts about my mason/solitary bee nesting houses)
The weather has finally warmed up and dandelions are blooming at last! All my little mason bees have begun emerging from their cocoons. The males usually emerge first, and hang around the nest boxes waiting to pounce on the females when they hatch out of the cocoon tubes.  Today was my birthday, and it was also the birth day of many of the little solitary bees in the nesting boxes on my kitchen porch.

I was lucky enough to get some good photos today of one pair of my new tiny horn faced bees mating! The female has two small 'horns' jutting straight out from her face, she uses them to pack mud into the nesting cavities, thus making an individual chamber for each egg she lays.

Here are two pictures of the amorous couple, the smaller male positioned on top. Click on the pictures and you'll see nice big close ups:

I watched as the male performed some strange moves repeatedly. First he would hike his abdomen very high in the air...

Then he swung it back down and curled it tightly into a very hunched position...
He repeated these odd up/down 'hand stand curls' many times while holding the female still. I couldn't see that he was even making any sexual connection during all this, but I suppose he must have been taking care of business somehow-  lol!   After a while they stayed still for a while as in the first photo. Then the male unceremoniously flew off.  A 'one night stand'.  I watched to see what the female would do next...

Right after the male flew away, the female dragged her behind and squirted out this cream colored droplet and walked forward a few steps.  She cleaned her face for a moment, then flew off too. This droplet reminded me of watching bees poop, but the mason bee poo I have observed is gray, while honeybee poo is orange-brown. The mason bees poop immediately upon emerging from their cocoon before they go anywhere, and this female had probably already done that before mating.
This was a thinner liquid, and almost white.  At any rate, she seemed satisfied with her birthday's chain of events and went on her way.  See her little face horns?  She also has shorter antennae than the smaller male.  She's off to find food, pollinate flowers, and starting nesting!


  1. What a fantastic thing to witness. And photograph! Thanks for sharing.

  2. Hi Strumelia,
    Great to read again how well your mason bees are doing.

    It seems that my mason bee females are pinned down within seconds of their cocoon emergence (before wing groom and poop) so I would be surprised if the post-coital poop you mentioned was any different to one before.

    Great that you captured the male gymnastics!

  3. Thanks Paul. Yes, male calisthenics....lol!