Bee hotel guests

Bee hotels are very popular at the moment. Most garden centres sell them, and they are advertised as homes for solitary bees. Solitary bees do use these bee hotels to make their nests, but once you get guests, how to tell them apart?
I was inspired to write this post after a twitter exchange starting with this message:

There appear to be about 225 species of solitary bee - think id unlikely!!! But so pleased something is using bee box :)
— Ragged Robin (@CarolineIrwin3) July 13, 2013

 With this post, I hope to give you an overview of what species of bees are likely to use bee hotels. In fact, only a small number of the over 250 species of solitary bees in the UK are likely to use bee hotels, so, with a bit of patience, identification is likely. For a start, not all solitary bees use bee hotels as they do not nest in cavities. Many solitary bees nest in the soil (the mining bees), others prefer the mortar of walls, or dig their nests in dead wood, or prefer much smaller holes or crevices than those provided in commercial bee hotels, which are usually made out of bamboo or reed canes. Mind, you, many more solitary bee species will be found in your garden than the ones that use the bee hotel. Once a female bee choses a tube in the bee hotel for nesting, you are likely to notice some activity, as she stocks the nest with nectar and pollen, lays eggs and builds partitions between the cells where her offspring will grow. Once she runs out of space in one tube she makes a stout plug and may start to fill another tube with more cells. The males searching for females or patrolling the area of the bee hotel can also bee noticeable.
 In addition to bees, other insects like some digger wasps or the cuckoo bees or flies that parasitise the bees themselves or spiders will also be seen on or near the bee hotel. My experience is on the north of England, and with home made bee hotels made by drilling holes in pieces of wood, so it is likely a few more species will be found to use bee hotels in the south.
 For identification purposes, time of the year, general size of the bee (use a honeybee as a guide) and colour patterns are useful. Also, it is very helpful if you can check what the bees are carrying as nest materials and the colour of the brush of hairs under the bees' abdomen that they use to carry pollen. The material of the plug covering the finished nests can also provide information as to what species built it. Once you can recognise the species or species group of the bees using your hotel, they are bound to provide an endless source of fascination, and bee watching may be addictive, so make sure you place your bee hotel in a spot you can easily and comfortably watch at close quarters!

Red Mason Bees
These are likely to be the first bees in spring using a bee hotel and the most likely species to use bee hotels. The bees are active from March to May. The females are reddish, with large, black heads, and size similar to honeybees. They have characteristic 'horns' on their faces, which they use to mould mud (above). Males are also reddish, smaller and with a white moustache. Males often sit on or near the bee hotel, sunbathing and looking for females.
  Mason bees use mud to partition cells in the bee hotel holes. They will travel from the bee hotel to the edge of ponds where they fetch mud, a little pellet at a time. Click here for more posts on Red Mason Bees in BugBlog.

Blue Mason Bees
These are much smaller bees and there are two similar species, Osmia leaiana and Osmia caerulescens (the blue mason bee proper). Males of both species are metallic green. They like to sit on the nest or stones or leaves at low level to sunbathe and from there they do patrolling flights in search of females. The females are metallic dark blue with a dark pollen brush underneath (O. caerulescens) or dark brown with an orange pollen rush (O. leaiana, above). Both species use chewed leaves to partition their cells.

Leaf-Cutter Bees
These are high summer bees, flying from mid May to August. I have two species in the garden, a large one and a small one. There are other common species in the UK, so care should be taken with identification. The male of the large species, Megachile willughbiella, is easier to identify, as it sports white-golden mittens on its front legs, which are very visible as he sits on the nest or sunny spots and grooms himself. Other identification features are the colour of the pollen brush on the underside of the abdomen: either orange (in the smaller species M. centuncularis, above) or red and black in M. willughiella (below). It is worth checking your bee hotel in poor weather, as these sun-loving bees like to use it as shelter in cold or wet conditions. More on leaf-cutter bees in BugBlog.

 Female Megachile willughbiella. Note the red and black brush of hairs under abdomen

Megachile willughbiella male. Note the pale 'mittens' on his front legs.

A few photos of the looks of the finished nests follows.

Two M. willughbiella males with two Osmia rufa (grey mortar looking) and a O. leaiana/caerulescens at the top, which is made of chewed leaves). 

A completed nest of a leaf cutter bee, Megachile. They use circular sections of leaves to make their nests.

Two recently completed nests of Osmia leaiana/caerulescens (I suspect the former, which in the last few days has been feeding on knapweed). Photo taken today.

The same area of the bee hotel on the 11th of May, just an Osmia rufa nest had been completed then.

Other bees that are known to use bee hotels in the UK are Chelostoma florisommne and Chelostoma campanularum, other Megachile species and Ectemnius digger wasps.

Ectemnius sp. a digger wasp, emerging from its nest.

More on Bee Hotels
Buglife.
Bees Wasps and Ants Recording Society.
Natural History Museum

Summery wildlife garden

A walk around the lush meadows of the wildlife garden yielded a number of invertebrate sightings. The day flying Six Spot Burnet moths, with their bright red-pink and dark metallic wings feasted on the knapweed (above).

A Meadow Brown feeds on the abundant oregano.

I caught a Small Skipper and a Six spot burnet on knapweed.

These are two shots of Small Skippers, one of my favourite butterflies. The way they carry their wings, held at different angles, instead of pressed together like other butterflies, is quite characteristic.

On the grass, there were many nursery webs of the nursery web spider Pisaura mirabilis. With a bit of patience, the guarding females could be spotted on or under the tents. She guards the eggs, and then the spiderlings which hatch inside the nursery web and remain in it for a few days.

A female Pisaura mirabilis.

My first summer generation Comma Butterfly.

And the first Gatekeepers. These two weren't wasting any time and were mating

Male Gatekeeper.

A Ringlet sat atop a ragwort inflorescence. Once I got closer, I realised the butterfly was dead, prey for a spider that often builds its web under flowers, Enophlognatha ovata.

This large hoverfly is one of my favourites, Chrysotoxum festivum. I often see a male hovering over the pond in the wildlife garden.

I took this shot on the 9th of July this year of the hovering male.

And in the oregano, a cuckoo bumblebee, Bombus ruderarius rupestris which parasitizes the similar looking Bombus lapidarius.

Crab spider stalking fly

I spotted this crab spider in my local wildlife garden, it had this strange clock-work movement and grabbed my attention. Then I spotted the fly. The crab spider, a female Xysticus cristatus, legs outstretched, on the left of the photo. The large fly is on the right, having fed or drank from the base of a teasel leaf. If you want to know what happened next see this video.

Early Thorn moth

While watering the garden earlier, I disturbed a large moth, an Early Thorn, Selenia dentaria. It settled adopting an unusual posture for a moth: wings up together, like a butterfly dangling from a leaf. Its scalloped wings, general tone and pale crescent mark underneath its wings was very reminiscent of a Comma Butterfly. Both species are very cryptic when resting, resembling a brown, shrivelled up leaf. The moth had a turgid abdomen, a female full of eggs. When I tried to pick it up it played dead, or should I say, it played leaf? It clung sideways to the side of the bug pot, occasionally twitching its legs, and then laid on its side at the bottom of the white bowl. I touched it gently and again twitched its legs, refusing to stand up or fly. After half an hour, it hadn't moved. After 45 min, I went to check again. The moth had climbed to the bug pot and had started to lay eggs! I promptly moved it back to the ivy, from where I had originally disturbed it, but I am the proud owner of 10 Early Thorn eggs. I'll give it a go to rear them when they hatch, as they are generalist feeders. There are two generations of Early Thorn, this moth belongs to the second. The larvae look like dead twigs, the adults like dead leaves. There seems to be a logic to it.

Playing dead

Early thorn laying

My bug pot eggs (note to self: I need a new bug pot!)

I left the moth to lay the rest of her eggs outside.

Black and Yellow Cranefly

With the warm temperatures of the last few days, I leave my office window open, and insects get in at night. This morning, arriving to work I found this cranefly, likely Nephrotoma flavipalpis, recognisable by the dark spot towards the end of its wings and mostly yellow head. Its bulbous - as opposed to pointy - abdomen indicates it is a male. He landed on the box of the Concise Edition of BWP, which provided a suitable white background, although the leg of a flamingo is visible in the photo below.

Silverfish

I found two silverfish, Lepisma saccharina, around midnight, as they scuttled about on the conservatory floor. I very rarely come across silverfish at home. A few months back I managed to squish one by accident while taking some shots on the white bowl, as they have soft bodies. To make sure, this time I left them in situ for photos.
  Their metallic shininess stems from the tiny scales that cover their bodies. They appear to drag their abdomen and are quite 'bendy' as they move about. These features together with their general shape gave them their common name. Silverfish belong to a group of wingless insects, the Thysanura, which have long antennae and three prongs at the end of the abdomen and split from the ancestors of winged insects in the early Carboniferous over 250 million years ago, before they developed wings. Unlike other thysanurans that are blind, Lepisma saccharina has small eyes, despite their nocturnal activity patterns.
  Silverfish are often found inside houses, usually in damp areas and are omnivorous, feeding on starchy substances, including binding materials for books, paper, moults of other bugs and other detritus.

More information
Timetree

Ringlet

I watched two Ringlets in the wildlife garden with their characteristic bobbing, low flight amongst the grasses. They looked like they would never settle, but this one did, and it posed beautifully for me for quite a while, allowing close approximation. It's lighter underside colour indicates is likely to be a female. Ringlets live in woodland glades and meadows with long, coarse grasses, their larval food plant. Adults are quite short lived, and their flight season is mainly July.

Pirate spider

I spotted this Pirate Wolf spider yesterday, which goes with wonderful latin name of Pirata piraticus on the pond of my local wildlife garden. There are several British species, most of them found in marshy habitats. These spiders are not only able to move easily on the wet vegetation, but they can run, walk and stand on water, as this one shows. They can even submerge, surrounded by a bubble of air, in case of danger.

Tree bumblebee threesome

This mass of bumblebees landed heavily in front of us. A Queen Tree bumblebee, Bombus hypnorum, and two males, the one ar the rear mating with her, the other one trying too. Quite impressive she just managed to fly with the load!
 In most bumblebee species, queens mate just once, but Tree Bumblebees are an exception, and queens often mate with more than one male. In experiments by Brown and colleagues, 72 queens that had mated the previous day were offered the chance of mating again. Sixteen of them (22%) mated again. The shorter the mating on the first instance the higher the chance the queens would choose to remate. The average copulation duration was about half an hour.
 Paxton and coworkers (2001) analysed queens, workers and males of 14 Tree Bumblebee colonies using very variable genetic markers. They wanted to find out how many males had fathered the colonies workers, and therefore, the level of relatedness between workers. They found that workers of single colonies are the offspring of up to six males, although most of them (60%) were full siblings, os normally one male sires most of the queen's offspring. A further, very interesting finding was the presence of a few number of 'alien' workers in some nests, which although unrelated to the queen were related amongst them. Their explanation for this was that a nest usurpation, a phenomenon that occurs in bumblebees, had taken place. In the spring, after emergence from overwintering, there is high competition for nest sites amongst queens. In tree bumblebees nest boxes and under eaves are favoured, and dead queens are often found just outside occupied nests. Why would this nest usurpation take place and what are the consequences? Usurper queens take over a ready made, established nest with some larvae or pupae - so they are already ahead of the competition with no effort. From then on, the usurper queen rears the already present larvae or pupae, which, when workers will help her rear her own offspring (in the same way that cuckoo bumblebees take over colonies of other species). Without genetic analysis, the success of not of the usurpation events couldn't be assessed, who was the dead queen, the usurper of the initial queen that had established the nest? The fact that the 'alien' workers were small, suggests that they were produced early in the life of the colony, when the queen had to feed the larvae herself. The fact that they were related amongst them rules out that they are 'lost' workers that  have entered the wrong nest. The alien workers were presumably early produced offspring of an usurped queen and had helped rear the offspring of the usurper, so they were effectively 'slaves'.

More information
Paxton RJ, Thorén PA, Estoup A, & Tengö J (2001). Queen-worker conflict over male production and the sex ratio in a facultatively polyandrous bumblebee, Bombus hypnorum: the consequences of nest usurpation. Molecular ecology, 10 (10), 2489-98 PMID: 11742549

Brown, M. J. F., Baer, B., Schmid-Hempel, R., & Schmid-Hempel, P. (2002). Dynamics of multiple-mating in the bumble bee Bombus hypnorum. Insectes sociaux, 49(4), 315-319. DOI: 10.1007/PL00012654

More lesser stag beetles

My kids found two live Lesser Stag Beetles on the pavement near the tree stump, now covered on flowers, where they grow. I couldn't resist the photo opportunity. As they often get squished, we took them home for release in our log pile after a few photos. This year we have found 4 females (2 live, 2 squished) and this male. They are my favourite beetle, the males are so powerful looking but still they have nice large smiling eyes. If I tickled him on the head with a small stick, he raised the front of his body and opened his jaws wide (above), awesome!

Male on relaxed position.

Dorsal view

 Female (left) and male (right). This is one photo in which I positioned both individuals opposite each other. Note the differently sized head and mandibles, despite similar length. The surfacing of thorax and head are also different in both sexes, in the male they look matt, while in the female they are punctated and shiny. Both sexes dig soft, rotting wood with their legs. The male still had some wood stuck to his legs.

This view shows the 'tooth' on the jaws.

For more posts on Lesser Stag beetles on BugBlog click here.

Cock-tail beetle

We found this rove beetle, Ocypus sp. (possibly nitens) running across the garden patio. It lifted its tail briefly a couple of times, honouring one of its common names 'cock-tail beetle', but afterwards it decided to groom itself at the bottom of the white bowl. These are usually nocturnal and predatory, often found under stones and logs during the day. They are quite fast and usually hide before photos can be taken in their natural habitat.

UPDATE Fauna, from Wild about Britain, suggested that this is Tasgius (which used to be Ocypus). I am thinking T. ater, as it has a very shiny head. The enlarged tarsi makes it likely to be a male.