More news from the bee house

A third species of bee has moved into my new bee house this summer.  After the red mason bees and a blue mason bee, two female common yellow-face bees (Hylaeus communis) built their nests in 4mm holes.  These bees are tiny, around 6mm long, and are black and shiny rather than hairy because they carry pollen in a crop, not on their bodies like most bees.  The cell walls in the nest are made of a waterproof cellophane-like material, secreted from the bee's Dufour's gland (close to the sting) and applied with its tongue.

I first noticed them on 12th July but both were already hard at work so they must have begun a few days before.  Here is one of them with one cell complete and busy marking out the next one. (For an explanation of the mud wall at the back see below.)

Here is the other one, marking out cell walls with cellophane.

The next day I found another Hylaeus communis nest in the old bee house.  All the holes there are 8mm and must seem cavernous for this tiny bee.  She had also been hard at work for several days and was stacking her cells on top of and beside each other.

Each cell contains a porridge of pollen and nectar to sustain the growing larva.  Here you can see an egg in the front cell.  The egg is quite big compared with the size of the bee.

Here the eggs have hatched and the larvae are already well grown.

Here is the bee in the old bee house, hard at work on another cell wall.

  

She eventually ran out of steam (or eggs) after building about a dozen cells but sat around for a long time afterwards, tinkering with the last cell wall.  I last saw her on 10th August, over a month after she arrived.

A few days before the Hylaeus bees arrived something else (presumably a couple of solitary wasps) had built a few nest cells in the 4mm holes and then disappeared before the nests were complete.  The cells were separated by mud walls and provisioned with tiny paralysed grubs but I never saw what had put them there.  This is on the west side, with red mason nests above and below.

And this is on the east with what I presume is a tiny egg on the window in each cell.

A third wasp nest has only three completed cells but was sealed with mud at the entrance so that wasp thought its work was complete.  Only a couple of the wasp cells look viable but it will be interesting to see what emerges next summer.  Whatever it is may have to wait until the Hylaeus bees emerge as they are blocking the exit.

Solitary bees and wasps are targets for all sorts of parasitoids.  I noticed this female parasitoid wasp, Gasteruption jaculator, sniffing around but didn't see it enter any of the nests.

And this is a kleptoparasitic ruby-tailed wasp, Chrysis spp.

I already have plans for another bee house for next year, offering even more luxurious accommodation for all sorts of solitary bees and wasps.