Saturday, 25 October 2014

Overwintering lacewings

On a visit to a local nature reserve a couple of weeks ago I looked to the ceiling of one of the hides, hoping to find overwintering butterflies. I didn't find any, but realised the hide contained several hundred lacewing, loosely clustered together in groups all around the ceiling and wall edges. It is something I had never come across. I believe these are one of a group of similar lacewing species, Chysoperla carnea group. Some of the individuals have started to change colour.

Saturday, 11 October 2014

October spiders

I found quite a number of spiders today in a trip to my local wildlife garden. It was mild and sunny. Some spiders basked on the wall, like a couple of young Nursery Web spiders, Pisaura mirabilis, and a wolf spider (Pardosa sp.). Nearby, a pair of Linyphia triangularis. As I went for a walk today, I was surprised by a mature Araneus diadematus female hanging from a tree (above). She might have been disturbed in her web possibly by a bird and dropped to safety on her line of silk. When it is foggy, I have seen these spiders webs quite high up in trees.
Several Pisaura mirabilis, sat on the painted leaves on the sunny wall.
This one seems to have regenerated a few legs, notice that some legs are shorter and paler than the rest. These nursery web spiders will overwinter soon.
As will young wolf spiders, Pardosa sp. which were also on the wall.
A Linyphia triangularis, males guard the female web in this species, fighting any contenders with their long cheliceae. The female is on the left, the male - out of focus - on the right.
Metellina male with present for female? Male Metellina sp. will capture prey before attempting to court a female, and then mate with her as she is entertained with the present ('nuptial gift' as it is called). I found this mature male today and wondered if that is why it was carrying this present. Unfortunately, I didn't see the female.
And on the playground, under a window frame painted with some street art, this pink and fully grown Araneus diadematus.
I found this male Amaurobius similis on the kitchen wall, on the prowl tonight. It measured 8 mm long. I got a good view of palps allowing for species ID.
For more October spiders, check out the Flickr group #Arachtober or on twitter.

Tuesday, 7 October 2014

Hitchhiker crickets

For about a couple of weeks, my six year old daughter has been telling me about the crickets in her school playground. Crickets? surely they would be grasshoppers, I said dismissively. I shouldn't have doubted her identification abilities, as she confidently pointed at oak bush crickets when presented with photos in a field guide, and my husband and son also confirmed it. I was most intrigued, as bush crickets are rare north of the Humber. Last week I spent an embarrassing amount of time searching for the mystery crickets while the kids played after school, while other parents I know looked at me as if I was going nuts. 'I put in on the tree this morning', my daughter would said, 'I've seen four, no... five' I wondered if the kids throwing sticks to get at the conkers was also dislodging the crickets from the chestnut tree at play time. I searched and searched, and, although I did find some Field Grasshoppers, Chorthippus brunneus, nearby there was no sign of the crickets, so frustrating!
  Today, at school pick up time, she told me she had rescued one from a puddle under the chestnut tree. I searched and initially found none, but finally, I founf a live female and a very squished male on the ground, hoorray! Both were collected and taken home, and to my surprise they turned to be the Southern Oak Bush Cricket, Meconema medidionale, distinguished from the related Oak Bush Cricket by its stumpy wings and larger male cerci. Oak Bush Crickets are nocturnal and live in trees canopies, so they are thought to be under recorded, although they are attracted to light, so they turn up inside houses in the summer. Instead of singing by stridulating with their wings like other crickets do, males attract females by drumming with their rear legs on the substrate, and this sound can be audible up to 1 m away. They are predatory crickets, and feed on small insects like aphids and leaf-miners (including those of Cameraria ohridella, the Horse Chestnut leaf miner). Despite their name, they occur in many tree and bush species and are a late species, with adults found from mid August up to the first frosts.
 Since the 1960s, the Southern Oak Bush cricket expanded its distribution range from its original homeland in Italy throughout large areas of Northern Europe, and is now also found in North America. It was recorded in the UK for the first time in the autumn of 2001, and since then, it has spread north up to Nottinghamshire. Given its flightlessness, it is surprising how fast they are expanding. A study systematically searching for this species in the recently colonised Slovak and Czech Republics found that they are found mainly in urban habitats like parks or campsites, often with localised populations near car parks and main roads, suggesting that they might be dispersed passively by vehicles, especially trucks and caravans. They are, unexpectedly, often found on vehicles.
 The fact that several individuals are present suggests that the crickets have been around for a while in the school grounds. Would a teacher returning from a visit down south might be responsible from the introduction of this cricket species in Hull?
The squished male
Side view of the female
UPDATE 8/10/2014
We released the female on the chestnut tree. Although she had lost a leg, she was quite capable of jumping, and hid under a shrivelled leaf. I found a freshly dead male in the same spot, quite intact. Here he is. Look how much longer his antennae are compared to the female.

More information
British Orthoptera & Allied insects page. Here.

Grabenweger, G., Kehrli, P., Schlick‐Steiner, B., Steiner, F., Stolz, M., & Bacher, S. (2005). Predator complex of the horse chestnut leafminer Cameraria ohridella: identification and impact assessment. Journal of Applied Entomology, 129: 353-362.

Vlk, R., Balvín, O., Krištín, A., Marhoul, P., & Hrúz, V. (2012). Distribution of the Southern Oak Bush-cricket Meconema meridionale (Orthoptera, Tettigoniidae) in the Czech Republic and Slovakia. Folia Oecologica 39(2) 155-165.

Liana, A., & Michalcewicz, J. (2014). Meconema Meridionale Costa, 1860 (Orthoptera: Tettigonioidea: Meconematidae)–The First Record In Poland. Polish Journal of Entomology, 83(3), 181-188.

Friday, 19 September 2014

Nervous sac spider

I met this spider while upturning a garden chair. She walked steadily on the ground, and blankly refused to settle on the white bowl. She jumped a few times like a jumping spider! I had to take the photos while she settled briefly on my plastic pot on top of the while bowl. The is a relatively large sac spider, Clubiona sp. (possibly reclusa), around 9 mm long, with very dark chelicerae. Females a silk cell in a folded leaf containing their egg sac

Tuesday, 16 September 2014

Blue lace web spider portrait

I enticed some blue lace web spiders, Amaurobius similis, out of their retreats gently spraying their webs with water. They are shy spiders and might swiftly come inside when realising it is not prey, but some stay out long enough. The one above was one of several in ivy, where I find they are quite common. She looks lovely, both powerful and fresh. The one below, a much darker individual lives on the corner of my fence. Both are mature females, the size of a honeybee.

Hawthorn shieldbug and garden spiders

 At this time of year it is hard not to notice Araneus diadematus, the garden spider. You walk through their orb webs when walking on paths with many hanging by each other by the dozens in front gardens. Most of the individuals you see on their webs now are females. Males have reached maturity and forgot about feeding: mating is the only thing in their mind, so they move across stealthily, in search of just mature fertile females. Many of the females are now just growing their eggs, fattening up, feeding on the many insects still flying in the mild september. The one above got a Hawthorn Shieldbug and rapidly rolled it up with silk, biting it repeatedly. The stink of the bug seems not to bother the spider. It was a dry afternoon, so the tiny dropplets visible on the silk threads on the bottom-left corner of the photo are probably the glue what makes the web sticky.
 I have been photographing garden spiders in the last few days. They are an easy subject. You can find the same individuals day after day in the same spot and you can get very close without disturbing them.
I tried a white background with this one, placing a white card behind the spider outside.
This is the largest spider around, in a very leafy front garden.

Sunday, 14 September 2014

Motherly candy-striped spiders

I find maternal behaviour of spiders fascinating, and I keep an eye for it whenever the opportunity arises. When repotting my gingko bonsai on the 2nd of September, I noticed a couple of rolled leaves. They contained web shelters of Candy Striped Spiders Enoplognatha ovata/latimana. One of them had a female with her egg sac, the other already contained spiderlings (above). I checked today again, both females were guarding their spiderlings. The first one approached the entrance of her leaf to check what was causing the disturbance, the spiderlings clustering together like Araneus spiderling balls. The spiderlings have been in one of the nests for almost two weeks. Will the presence of their mother increase their chances of survival? will the mother feed during this time? In the related genus Theridion (Enoplognatha ovata was previoulsy called Theridion ovatum) the presence of the mother guarding the egg sac appears necessary for egg survival (although there were some loses due to parasitism from a tiny wasp). The mother not only sits near the egg sac, attached to her by a silk thread, but she is on the alert, and will move the egg sac to the centre of the web when predators are nearby. Unguarded egg sacs are rapidly predated by insects (ants, earwigs) and other spiders. And what about the spiderlings? what do they have to gain from their mother's care? In the Happy Face Spider, Theridion grallator, the female loosens the egg sac allowing the emergence of the spiderlings, and then captures prey for her brood. The spiderlings are under the female care up to three months, until they disperse and feed on their own. The female might produce another egg sac if the first one is lost, but she will die by the end of September early October. The spiderlings will disperse and overwinter near the ground.
One of the females, in close contact with her egg sac (2/9/14)

More information

Friday, 12 September 2014

Land flatworm

Some posts take a long time to come out. This one in particular has been on the shelf for a long time. The reason? I wasn't sure of the identity of the animal for a while. I found it under a stone on the 29th of September 2012. A small, shiny white long thing, looking like a piece of root, but then it moved! What on earth was it? I picked it up and placed it on the white bowl, where its paleness didn't contrast as brutally with the background. A very stretchy animal, with no rings or setae: cannot be a nematode or an annelid... a flatworm? I got excited, a land flatworm, wow!, I didn't know we got these in gardens. Then I thought, wait a minute, isn't there an invasive land flatworm? I researched the topic. Yes, there are three species of native British land planarians...and at the turn of the XXI century 10 introduced species. After some inquiries it turned up mine was probably one of the native species, Microplana scharffi. Thank you to Christian Owen in iSpot who identified it for me.
The flatworm with its head up

Elephant hawkmoth and caterpillar eyespots

While visiting a farm in the Peak District, we stumbled with this awesome mini beast: a fully grown Elephant Hawkmoth caterpillar. I had been wanting to see this caterpillar for a long time. Knowing that they like willowherbs I had often look for them when I saw a drift of rosebay willowherb. But not this time, somehow, its dark colour made it stand up against the green foliage. She was hanging upside down from the underside of a rosebay willowherb leaf, on a plant growing by a hedge.
 While handling it it adopted all the postures this caterpillar is known for, suggesting either an elephant, when the caterpillar is fully extended, or a snake, when the caterpillar is disturbed and it raises its front, while retracting its head.
 A 'snake' resemblance is a recurrent theme in various large caterpillars from several families, and it has been suggested that this way the caterpillars gain protention from birds, wary of snakes, which are startled when the caterpillar moves its head and the eyes are exposed on the thickened anterior end.
 A Canadian team formed by Thomas Hossie and Thomas Sherrat carried out an interesting set of experiments using pastry caterpillars, which they exposed to natural predation by placing them in branches in the wild. They used pastry caterpillars coloured with food dye with or without eyespots with or without defensive posture ('snake') and with or without countershading.Their results suggested that the presence of eyespots and the raised position might deter birds from eating the caterpillars and countershading and the position of the eyespots in the thickened anterior end has a protective effect too. But don't rely on me telling you, as you can read it from Hossie's himself in his blog Caterpillar Eyespots.
A close up of the eyespots.
The 'elephant' pose.
and the 'snake' pose
another angle of the snake pose
And of the elephant pose.
The happy caterpillar munching away on its new home.

Sunday, 31 August 2014

Three bright characters for the end of August

Some invertebrates appear as heralds of autumn, and today three striking ones were present in the garden. Migrant Hawkers have been around for a while, forming loose swarms that hunt between 2 and 8 m high, often well away from water. In the cooler, shorter days of late summer it becomes easier to come across sunbathing ones, perched on a branch, often more than one near each other. I flushed this male a few times as I went about in the garden, until I finally spotted him hanging from its perch. I got so close taking the macro above that I could have kissed him.
A single Red Admiral was also about, alternating between feeding in the buddleia and basking on a brick wall. During sunny spells she closed its wings, while during passing clouds she revealed its fresh, amazingly marked wings to their full splendor. This was a beautifully marked individual, the small, delicate blue markings on the edge of its wings very apparent.

I used the flash to counteract the sunshine and reveal the intricate patterning of the underwings, which can make the butterfly well camouflaged.
This garden spider, Araneus diadematus, is one of the largest in the garden, she hangs her web on the side of the rubbish bin, and has her retreat under the rim. Given the size of this species, detailed inspection of the epigyne is possible without even disturbing the spider (click on the photo to see it).

Thursday, 28 August 2014

Common Darters

There were at least two male Common Darters, Sympetrum striolatum, around the wildlife garden pond today. If you move slowly, they are great posers and allow very close approximation. Their faces are locked into a perpetual smiling grimace, adding to their charm. If you watch them from a close distance,  you'll notice that they are constantly flicking their heads around, looking for insects flying overhead. If a suitable one is detected, they dart off, returning to their perch to eat their prey.

The ever smiling darter
A short clip of the darter watching for prey.

Male garden spider

We found this male garden spider, Araneus diadematus, on our garden gate, actively walking about. Male garden spiders are on the lookout for females in August and September, when they become adult and receptive. This was a large and handsomely marked male, so I gave it a session on the white bowl and then released him near the largest female in the garden.

Hunting wasps

There are few things reminding me more of the end of summer than hunting wasps. Today, a buzzing ball of fury fell on the pavement in front of me. A common wasp, Vespula vulgaris, holding on a male Eristalis dronefly, desperately trying to escape. The wasp held onto the dronefly's legs, chewing three of them and a wing off, and rendering the dronefly defenceless.
A loose leg and a wing are visible
I was amazed by the determination of the wasp, which was thrown about by the hoverfly while it was only holding by the hoverfly's abdomen.A very short clip shows moments after they landed.

Thursday, 14 August 2014

A glimpse of Zygiella mating

 By chance while in the garden a couple of days ago, I spotted two small spiders near each other, which immediately attracted my attention. The smaller spider, which I could now see it was a male, proceeded to approach the passive female and insert one of his palps in her epigyne. After a few seconds, he retreated and repeated the process with the other palp. The translucent inflated palp is just visible in the photo above, where the female is on the right. A gust of wind separated the spiders and, despite the male's apparent efforts to find her partner, thus ended their affair. The female now rested atop a flower stem and I could watch and identify her by the pale leaf pattern on her back and ringed legs: a missing sector orb web spider, Zygiella x-notata.
 Given how slow spider courtship may be, in particular the slow initial male's approach to an often aggressive female, I count myself lucky to have witnessed the mating of yet another spider in the garden.
The female Zygiella x-notata

Wednesday, 23 July 2014

Insects in flight

Today it was a summery, hot day, with a light breeze, ideal for insect watching. Somehow, I managed a few decent in flight shots, which usually evade me as I am not patient enough. The first one happened when I spotted two hovering Volucella pellucens. They are large hoverflies, which live near trees and are identifiable even at several meters of distance due to their translucent abdominal belt. Males hover incessantly on the same spot, and inspect or chase off other hoverflies and even speckled woods invading their territory, so maybe this way they spot female hoverflies to mate. Hoverflies also hover during courtship. I tried to encourage them to sit on my finger by slowly raising it towards the hoverfly. This technique often works with hovering males, like this Eristalis intricarius from yesterday shows:
but the Volucella refused several times...
So I tried to get some shots while it hovered and got the shot at the top of the post, and I was pretty pleased with that!
 A bit later, then, in my street, a couple of migrant hawkers were hunting over the verges. Migrant hawkers often hunt together with other individuals, and they may settle to bask near each other. They tend to hunt from 4-5 m above ground. I managed some records shots, this one the best.
I popped in the wildlife garden later to release a grasshopper (a matter for a different post) and watched a large Ectemnius digger wasp (probably the common E. cavifrons) inspecting a rotten log. She had to fend off a Tegenaria spider. Ectemnius are hoverfly hunters and are skilful hovers. Females dig their nests in soft wood, and look by suitable nest sites, often hovering in front of the wood. This allowed me an opportunity for the third flight shot for the day.