A ruby-tailed burglar

Parasites seem to be dominant over hosts in the bee house this year.  I watched a mason wasp putting the finishing touches to her nest, blocking up the entrance with mud.

I wasn't the only watcher.  There were several ruby-tailed wasps waiting around.  They are cuckoo wasps and lay their eggs in the nest of other solitary wasps.

One in particular taking a close interest in what was going on.

Eventually the mason wasp was satisfied and after a last look round she flew away.

Within a few minutes the ruby-tailed wasp had returned to the nest and started to chew out the mud seal.

It took 25 minutes of chewing.

You can see her ovipositor is extended ready for action.

Then she suddenly turned around to lay her own egg in the nest.

That took only a few moments and she was off, perhaps to seek another victim.

As I understand it, the mason wasp lays a series of eggs in different cells along the length of the nest, separated by mud wall in the same was a a mason bee so I presume the ruby-tailed wasp, with a short ovipositor, can only parasitise the front cell.  I hope I'll be watching to see what emerges next year.

PS.  The photos are attracting a lot of attention on Facebook.  The experts on the BWARS page say the mason wasp is Symmorphus bifasciatus and the ruby-tailed wasp is likely to be Chrysis angustula.

Yet another thing to worry about

It is a hard life being a solitary bee or wasp.  This season is turning out to be particularly difficult with poor weather and high levels of parasitisation.  The red mason bees have had an especially bad time this year (more on that to follow).

While I was watching the bee house the other day I spotted this shifty-looking fly, loitering with intent.  It wasn't one I recognised so I took its photo, planning to report it to the authorities.  It turns out to be Eustalomiya festiva, aka as the Sub-plumose Log Fly, an ID subsequently confirmed on the UK Diptera Facebook page.

On Steven Falk's Flickr site he says " E. festiva is fairly frequent throughout the southern half of Britain, becoming scarcer in northern England and Scotland.  It is typically found around dead and fallen tree trunks and log piles [of which I have plenty] in sunny sheltered locations in and around woodland.".  He goes on to say "The larvae are cleptoparasites of wood-nesting crabronid wasps such as Ectemnius and probably Pemphredon species", both of which are present in the garden.

I have reported it to iRecord and it is the first record for the north-east of England.  I doubt if it is rare here but there may not be so many dipterists in these parts.  Flies look really difficult and complicated so I am not tempted to become one.

News from the bee house

Fortunately the solitary bee season coincided with warm sunny weather in late spring and early summer.  Now it is wet and gloomy the season is almost over but it has been fascinating to watch and mostly very successful for the bees.  The most numerous residents of the bee houses are always red mason bees.  This is a female in the observation wing having a brief rest before setting off to forage again.

In most previous years I have had between half a dozen and a dozen completed red mason bee nests.  This year, with my new bee house, I have about 80!  Here are 34 of them.

In the next photo the rear cell is complete with a food store of pollen and nectar and an egg. Work has started on the front one contains a bit of pollen and a pool of regurgitated nectar.

A few days later it looks like this.

Here is another bee coming back with a load of pollen.

The bees always reverse in to unload pollen.

Here are a couple of bees plugging the entrances to their nests.

There was one blue mason bee nest from last year with nine cells.  The front six were males. This is one of them.

Once they had chewed their way out of their cocoons five of them sat in the nest for another 24 hours before deciding to brave the outside world.

The females emerged a few days later and one of them moved into my new bee house.

She uses chewed leaves rather than mud to the build the cells.

Here she is in the precess of laying an egg.

Another bee in the new house was a common yellow face bee (Hylaeus communis) but she completed only three cells.  She made several more cellophane walls along the hole before sealing it so three was all she planned.  The nectar pollen mix she brought in was almost black.

The observation part of my original bee house is still in use and this year, for the first time, it was host to a leafcutter bee.  I was very pleased until I realised that she was lining the cells first before working on them so I couldn't see what was going on!  The nest was in an old red mason nest, hence the mud lining.

The bee house has a wire mesh covering as protection against woodpeckers.  Rather than risk dropping the leaf if she flew through the mesh, this bee flew in the bottom each time and then flew vertically upwards to reach the nest.

I was struck by the precision in the final work to seal the nest.

Another resident of the "bee" house was a mason wasp, a solitary wasp that uses mud in the same way as the red mason bee does.  It used a smaller hole and filled the cells with caterpillars rather than pollen.  Here it is clearing out sawdust before starting to build cells, with a red mason bee in the background.

There were other solitary wasps which were tiny.  They made their own holes in the wood, about 1mm in diameter, and stocked them with aphids.  Louise Hislop, our local bee & wasp expert, says they are Passaloecus sp. females.

Perhaps the most exciting bees I saw in the bee house were fork-tailed flower bees.  They nest in rotten wood so I made one panel out of dried rotten wood, specifically in the hope that they would move in.  I made three small starter holes and was surprised and delighted to see that for several days two of them were excavated by female fork-tailed flower bees.  But although I often saw the bees pushing their way out through clouds of sawdust I never saw them going in with pollen.  I wonder if they didn't fancy the holes after all after all that digging.  With luck they did continue when I wasn't looking.  I'll be able to remove the panel later in the year to take a look.

I am already making plans for next year, to make sure there will be room for perhaps an even larger population of bees.

My new bee house

I have just finished making the new, improved, deluxe, mark IV bee house (2023 model).  The central section is fairly conventional but also contains a solid piece of rotten wood, in the hope of attracting fork-tailed flower bees.  The side doors are recycled from my old kitchen units.  They extend in front of the rest of the house so I can put on a wire mesh to protect against woodpeckers and blue tits.

The side panels are covered by perspex so I shall be able to see the occupants.  Three are made out of dead sycamore and the fourth out of rotten dead sycamore.  It was interesting machining the wood but I hope it will have been worth it.  I have put in a mixture of 3, 4, 6 and 8mm holes to attract a variety of species.

The panel with rotten dead wood has just three short starter holes because fork-tailed flower bees apparently like to excavate their own holes.  If one does come in I hope it will stay next to the perspex so I can see what it is up to.

I have transferred canes and tubes etc, some of which contain bees, from the mark I bee house which is now retired.  (The mark II and the mark III are still in use.)

Since taking the above photos I have modified the top section with another log to make it easier for bees using that to get their bearings and I have fitted a clip-on wire cover to protect against blue tits and woodpeckers.  The bees can easily fly through the mesh and I can remove it for photos.

So it's all set to go.  I'll report back later in the spring or summer on which bees have moved into this luxury accommodation.

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.