Friday, 31 July 2015

More skippers!

The sun shone finally after a wet and cool week. We popped in the wildlife garden in the afternoon. The knapweed, a favourite feeding plant for the skippers is now flowering in the meadow. Both species were very active, a male Large Skipper fed on the flowers, showing its long tongue.
A male Small Skippers followed a female fluttering behind her, but then appeared to lose interest, quickly losing her and perching, maybe she was already mated? The female settle to feed almost next to him and I just managed to take a photo with both in the frame: the male is in the foreground.
 We watched possibly the same female later as she was searching for suitable oviposition sites, which in the case of Small Skippers is Yorkshire Fog grass.  She settled and started a curious dance on the long grass stems, her swollen abdomen curved and everted, its tip touching the stem, and she moved circling around and up like moonwalking. We didn't actually see any eggs (they must be tiny!), but this confirms that the garden has a breeding population.
This gif showis a short sequence of egg laying behaviour:

Thursday, 30 July 2015

Male mouse spider

As I lifted a towel from the kitchen floor, a male Mouse Spider, Scotophaeus blackwalli, ran out. He was quickly potted and had a brief session in the white bowl. These spiders are usually cooperative, and they freeze for a while when disturbed, which is enough for me. This is the time of the year when Mouse Spiders are mature and look for potential mates and I wonder if that's what this male was doing. These spiders are strongly associated to humans, and are mostly found in or around buildings, sheds and gardens, which suggests they have expanded from a more southern origin. Scotophaeus males only have slightly enlarged palps compared to other spiders, but they are still thicker than the female's, this and the very narrow abdomen of the male helps distinguish the sexes.

Wednesday, 29 July 2015

Trespassing old lady

This Old Lady moth, Mormo maura, entered a bedroom earlier tonight, and I took its photo as it sat on the wall. This is a large moth, which looks like is wearing a long dark cloak, hence its name. Although nocturnal, it is not attracted to lights, but it appears inside the house, often (but fortunately not tonight) brought in by the cats, but also possibly to roost. It feeds on buddleia and other flowers at night, while the caterpillars feed on blackthorn. It is a local species, but a regular in the garden, with my records from mid July to mid September. I found this grown larvae on a windowsill a few years ago.
Old Lady caterpillar 30/04/2008

Sunday, 26 July 2015

Cucumber spider with egg sac

 While looking for lily beetles, I found this female Araniella sp guarding its egg sac. The sac, made of coarse yellow silk threads, was attached to the underside of a leaf, and the female sat on a loose web underneath, where she was also eating an aphid (below). There are two extremely similar species, Araniella cucurbitina and A. opistographa, which can only be identified by inspection of their epigyne. Both are small and bright green, with a red mark over their spinnerets, which can often be seen from underneath. They live in trees and bushes, and are orb weavers, although their webs are quite small.

Friday, 24 July 2015

Yellow dung fly

This male Yellow dung fly, Scathophaga stercoraria, as the sole occupant of a very wet cowpat after a rain shower. Yellow dung flies are sexually dimorphic, males and females differ in size and colour: males are much larger and brighter yellow than the female. Larger males are better competitors, better to defend a bit of cowpat from other males. Males spend much of their time on the cow pat, while females only come to the cowpat to mate and lay eggs. Dung flies actually feed on other flies and insects attracted to the dung, but also on pollen and nectar and the dung itself, while the larvae will develop on the dung. Although of Yellow Dung flies are associated to large animal dung, especially cow pats, I've had them in the garden before, where they might have been attracted to compost.
A pair of mate guarding dung flies in the garden, 26/08/2006, illustrating their sexual dimorphism.

Tuesday, 21 July 2015

Summer generation Holly Blue

The first Holly Blue of the summer generation. This butterfly has two main larval foodplants: spring generation females lay their eggs on the buds of holly, whereas summer generation ones lay on the buds of Ivy. Unlike the other blues, the Holly blue tends to fly high near trees and bushes.

Monday, 20 July 2015

Marmalade flies everywhere!

Marmalade flies, Episyrphus balteatus, are the most common British hoverfly, and can be seen year round as they are able to overwinter as adults. However, at this time of the year, they are at their most abundant, as I walk around the garden, every flowers seems to have a few males hovering nearby or females feeding on the flowers. These slim, small hoverfly is able to migrate, and this occasionally bumps the numbers of British individuals. They are very distinctive, as the pattern of double black lines in the abdomen is unique to this species. The male above (eyes meet at the top of the head in many male hoverflies), settled briefly on an Agapanthus flower bud, and rubbed its feet together, keeping its wing open for a few seconds.

Sunday, 19 July 2015

Small Skippers

There were many territorial male Small Skippers in a meadow area in the outskirts of town. The males look like little, golden triangles perched on grass tips or flower heads, which dart after passing butterflies hoping for a female skipper. Males and female skippers are easy to tell apart when perched, as males have a dark line parallel to the edge of their forewings, the 'sex brand'. The photo above shows a female, below, a male. Both sexes were enjoying the plentiful creeping thistle flowers.

Saturday, 18 July 2015

A pair of common field grasshoppers

 I found a pair of common field grasshoppers, Chorthippus brunneus, in the wildlife garden. They were basking on a stone near each other (see photo below) and I managed to approach closely, so that their distinctive hairy underside is visible. They are a variable species, with pink and orange forms, but this population is made of brown, mottled ones. They are winged, and therefore good colonisers, with their folded wings sticking beyond their knees. The male is smaller and has a brightly coloured abdomen and longer antennae. Check the species page of Orthoptera & Allied Insects for more information.

Friday, 17 July 2015

Bright batman hoverfly

Here, a female Myathropa florea basks on a leaf over the wildife garden pond, which is now almost dry. Although batman hoverfly is not its common name, the distinctive batman symbol on this fly thorax makes it very distinctive. This hoverfly has a very long breeding season and you can see it from April until November, where it is often seen feeding on Ivy flowers. Individuals may vary in their brightness and this is because those that develop at high temperatures are brighter (like the one above) than those growing at colder conditions. This is a very common, opportunistic hoverfly which breeds in rot holes in trees or other hollows with wet rotting vegetable matter, where their 'rat-tailed' maggot larvae develop.

More information
Stuart Ball & Roger Morris 2015 Britain's Hoverflies: A field guide. 2nd ed. Wild Guides.

Thursday, 16 July 2015

The nest robber

I was puzzled when I checked the bee hotel a couple of days ago. The painstaklingly, lovingly filled nesting cells of the Osmia leaiana nest that illustrated a post a few days ago were gone. There was pollen everwhere and the nest walls made of chewed leaves weren't there. A Megachile willughbiella female, a leafcutter bee, was inside, rubbing its scopa against the walls. Was she the reason for the disappearance of the smaller mason bee's nest or just taking advantage of a previous nest predator?
 Although I'll never know for sure, I think that the leafcutter is probably to blame. There are plenty of empty cavities in the bee hotel, but she apparently decided that this was a better hole than the rest and probably fought the mason bee out of her nest (Leafcutters have formidable scissor-like jaws, and this leafcutter species is a large bee), and then proceeded to empty the contents, eggs, pollen, nectar and walls to make space for her cells. Today, the leafcutter had completed her first cell (above). Note that the walls are still covered in yellow pollen.
 The bee nestbox is providing plenty of surprises and allowing observations very difficult to make in natural holes. The events illustrated here remind me that competition is fierce out there, although in the case of hole nesting bees, it will pass unnoticed in the darkness. Many bumblebee queens are ousted from their nests by other bumblebee queens, not necessarily from cleptoparasitic species, which take over after a fight. In solitary bees and wasps, suitable nest holes might be limiting and intra and intraspeficic competition might be rife, although fights may often take place inside holes. Watch this fascinating video of three bees fighting for a nest hole by George Pilkington, and this series of photos by Simon Saxton documenting two Ectemnius wasps fighting for a nest hole. Nest lining thicker end walls provides physical defence, and might not only protect against cleptoparasitism, but also against other bees taking over, stealing the nest hole and destroying the nest contents.
7th of July. A female Osmia leaiana working on her nest. Note the remains of last year's leafcutters nest in the cavity under it.
16th July, a female leafcutter emptying nest contents by scooping pollen.

Wednesday, 15 July 2015

Blue lace weaver guarding her egg sac

I found this blue lace weaver, Amaurobius similis, under a flagstone. Its eggs, wrapped on bright white silk, forming a semitransparent large egg sac, which she will guard until the spiderlings hatch. I have written previously on the extreme maternal behaviour of this spider, especially its production of a second batch of eggs for her first brood of spiderlings to feed on, and the matriphagous behaviour of her spiderligs. To read more click here.

Tuesday, 14 July 2015

A shiny forest shieldbug

A close up of a recently emerged forest shieldbug, Pentatoma rufipes, showing all its metallic shinyness.

Monday, 13 July 2015

Pirate spider eyespots?

Wolf Pirate Spiders (likely Pirata piraticus, but there is a similar species, P. tenuitarsis) are one of my favourite spiders, their existence in the boundary of water and land, and their ability to walk and run on water makes them fascinating. A few days ago at the wildlife garden, I discovered a curious fact about them while looking at a photo of a female carrying an egg sac. The female was lodged at an angle on some leaves and I did a double take: it gave me the impression that the abdomen of the spider was in fact, its face. This impression was due to two paired white spots on the female's abdomen looking like eyes. Instead of a spider facing away with her egg sac attached to its abdomen, it looked like a spider looking forward, while carrying its egg sac on its jaws, in the way of nursery web spiders. Pirate spider eyespots? Wolf pirate spiders have paired line of white spots on their abdomen, so I wondered if it was just this particular individual that casually had the spots in the shape and area to give this impression. I checked my photos of this spider and found at least two others with the same spots, one also carrying an egg sac. I also found other photos on the web of this species with the same abdominal spots.
Another Pirata sp with egg sac and 'eyespots' 22/07/2014, same habitat
For comparison, a female nursery web spider carrying her egg sac with her chelicerae.

 Only photos taken in a particular angle, of the spider facing away show this, and I guess everybody prefers a front shot of a spider, so I think this pattern is probably found in the species at least regularly, and not only in the females, this side view of the spider allows to see the larger spot towards the end of the line of spots in a male
A frontal view of the same male showing his enlarge palps:
Have these spots evolved due to them giving an impression of eyes to visual predators, as the eyespots found in some caterpillars and butterflies? In some cases eyespots function to startle a predator giving the impression of a different, larger animal (like the elephant moth caterpillar, the peacock butterfly or this amazing tropical caterpillar), instead, in the wolf pirate spider the eyespots would work like those found at the rear end of some fishes and butterflies, whose function might be to trick or confuse a predator as to where the head of the animal actually is. In fact, eyespots are not unheard of in spiders.
 Why would this be beneficial to this spider? What follows is only speculation, but apparently, wolf pirate spiders live in retreats in moss at the shore of ponds, and females carrying egg sacs often expose the egg sac to the sun at the retreat entrance, while the female remains inside. This could put the female in danger of predation, as she would be less able to detect danger, so the eyespots could afford some protection to the mother and its offspring to be, but I am not aware of any research into the evolution of these eyespots.

With thanks to Catherine Scott (@cataranea) for discussing this on twitter before I wrote the post.

Saturday, 11 July 2015

The woundwort shieldbug

If you have Hedge Woundwort in your garden, Stachys sylvatic you are bound to also have the small and shiny Woundwort Shieldbug, Eysarcoris venustissimus. The whole life cycle of this shieldbug takes place in the plant, they feed, mate, lay their eggs and their larvae feed on it too. They are capable flyers though, so they can easily disperse into new patches. I found this mating pair in the wildlife garden, and when I looked at the photo I noticed a nymph hidden in the seed head to the left of the individual at the bottom, and also a clutch of pale eggs under the seedhead over the individual on the top. The small nymphs look remarkably like the plant seeds green and black. In warm mornings the shieldbugs come to bask on the leaves of the plant, sometimes in large numbers. They are quite gregarious and nymphs and adults are often found side to side.

Friday, 10 July 2015

A cleptoparasite in the bee hotel

The Red Mason bee is well over in the garden. They have been replaced by their smaller relatives, Osmia leaiana. They have started nesting in the bee hotel and there are several females stocking their nests with nectar and pollen and sealing their nests with chewed up leaves. I removed the side panel of the nest box temporarily to see the progress of the nests. Below is a female with a clump of chewed leaves starting another cell. The yellow lumps are the food supply necessary to nurture one of her larvae to develop into an adult bee.  The bee needs many pollen collecting trips to complete a cell, and then many other trips to collect the leaves to build the cell that will seal each of her nests compartments.
Well, that's the mason bee's plan. However, there are other bees and wasps with their own intentions regarding these laboriously collected clumps of pollen and nectar: they are cleptoparasites. They will take advantage of a female bee outing in search of flowers, enter the nest and lay an egg next to the bees egg. The cleptoparasite egg either hatches earlier, or the parasite larva kill the bee larva to have the food to itself. One of these cleptoparasites is the wasp Sapyga quinquepunctata (above), a black, thin, long wasp with iridescent blue/purple wings and white marks on the abdomen. A female was around the bee hotel today. She inspected each hole, checking it there were bees in them and if they had cells in construction. One of the times, as she left the hole, a mason bee appeared in its entrance. The wasp is careful not to enter a nest containing a bee, presumably because the bees are aggressive to intruders (and have their stings to defend themselves).
This bee hotel with observation panels was designed by George Pilkington, check his website, where he has many informative videos and posts on solitary bees and bumblebees.

Thursday, 9 July 2015

Growing garden spiders

Some of the garden spiders are starting to reach good sizes. As soon as they become apparent I realise it's well into summer, and that despite the dismal weather spiders haven't stopped feeding and growing. This one is probably not quite yet mature, but it is likely to be a female.

Wednesday, 8 July 2015

Slug standing up

'Look, a slug standing up' called my 7 year old daughter. I went over by her and watched. Indeed, a Spanish Slug, Arion vulgaris, reared up as high as it could go in between some pots. It waved its body from side to side, and after some time it bent over itself turning round, touching its mucus pore with its head. I had seen this behaviour previously described in Rowson and colleagues' FSC guide 'Slugs of Britain and Ireland':
'Arionids are sometimes seen rearing up off the ground, as if sniffing the air' 
It is a curious behaviour of unclear function, are they really 'sniffing' the air? could they be sensing humidity in the air, assessing when to retreat to a refuge, or looking/smelling for food? Although slugs have very simple eyes, this rearing and moving side to side could allow them to assess where shadows are indicating plants to climb. Alternatively, they could be detecting or emitting pheromones to find or attract potential mates.

Tuesday, 7 July 2015

7 spot ladybird

Yesterday there was a gap in the 31dayswild theme this month, but not to worry, it wasn't so much due to my inability to see and photograph a suitable invertebrate, but more to the overabundance of them as I visited a local nature reserve, but you may want to go to my Wild at Hull blog to find out. So, continuing in today's stormy day 7, I bring you a fresh 7 spot ladybird. Despite the abundance of Harlequin ladybirds in the garden, 7 spots seem to be having a good season and I have seen them regularly this year. This one was giving this knapweed bud a good check for aphids.

Sunday, 5 July 2015

The knapweed bee

A few years ago I introduced some native knapweed in the garden. I planted them on the beds and they did well. However, the following year they didn't come back on the beds, they selfseeded in the cracks in the cement and now I have several large plants growing amongst pots from the cement. They attract many bees, but one in particular, enjoys this plant the most, the small mason bee Osmia leaiana. Males are beautiful golden bees with green eyes, while the females are dark, with an orange brush of hairs under they abdomen, which they use to collect pollen. They often dive head first into knapweed inflorescenced and their orange underside becomes quite visible.
 Today I was very pleased to find out these bees are using my bee hotels, I hope to get some photos of the cells they are stocking soon.

Saturday, 4 July 2015

MIni pond backswimmers

During mid May, I noticed lots of backswimmers in my tin bath pond. Since then they have diminished in numbers but grown in size, after several moults they are now about 1 cm long. They are Common Backswimmers, Notonecta glauca, one of the four British species. They swim on their backs, and come out to breath by touching the water surface with the tip of their abdomen. If you fish one out and put it in a small transparent container you might be able to see its white back by lifting the container and looking up. Mine have all white backs as they are not adults yet. They are predators of insects, which fall on the water and become trapped on the water surface, but as adults, they might catch small fish and tadpoles, and they are also cannibalistic. Avoid handling them, as they are said to be able to prick the skin with its mouth parts! They live in all sorts of ponds, including drinking troughs. They are winged and able to fly, and the adults can emerge out of water and disperse in search of new habitats.
 This is my bath pond (photo from last year, the lily is not yet flowering this year).

Friday, 3 July 2015

A just emerged Elephant Hawkmoth

In the early morning, we found this Elephant Hawkmoth, Deilephila elpenor, in the garden, on the base of the iron leg of a chimenea. It took us a bit to realise that it was fresh, just emerged from its pupal skin, wings still floppy. We moved it to a cat-safe location higher up on bushes, where she positioned herself again facing up, wings folded over her back as they filled up.
 Elephant Hawkmoth caterpillars feed on Rosebay Willowherb, Bedstraws and Fuschias. There is a fuschia overhanging our garden and many cleavers. It was nice to realise that this moth's amazing caterpillar, which gives its common name to the moth, grew somewhere in the garden, and pupated nearby on the soil.
 When I came back from work, in the evening, she was still hanging there, her wings hardened and opened (below). Hopefully she'll fly away tonight.

Thursday, 2 July 2015

A Southern Hawker

As I was about to leave the park this morning on my way to work I checked around an area of trees for Speckled Woods. Instead, I noticed a large dragonfly flying about and landing on a horse chestnut branch. I approached and searched for it. I had clearly seen where it had landed, but it took me a while to find it again. There! hanging from a leaf was a hawker. It rested, about 4 m high at an angle away from the sun, so it wasn't a great spot for photos, but after a while I managed this shot showing its features. As I checked the photo tonight thinking it's a bit early for Migrant Hawkers, I was pleasantly surprised to find that it was an immature Southern Hawker, which I have never seen in the area. Southern Hawkers breed in small ponds or canals, and often in garden ponds. After the adult dragonflies emerge from their native ponds, they spend about month away from water while they mature. Then they will find ponds where to breed. They like to feed on woodland glades, often away from their breeding ponds.

Semaphore flies

After a wildlife-packed June with the 30 days wild challenge, I felt like I needed a new focus and I decided to carry on a wildlife challenge by blogging/tweeting about an invertebrate I've seen that day for July. Yesterday, while walking by the local park pond I saw a Speckled Wood. The butterfly flew away, but it made me notice the flies dancing on the Colt's Foot leaves: they were Semaphore Flies, Poecilobothrus nobilitatus, a whole swarm of them signalling to each other. Although small, this species is very easy to identify by their smoky wings with a white tip. They are very active in July on muddy puddles and ponds.