Winter active spiders in the house

We are having an exceptionally mild winter and, although much of the time it is wet and dull, winter invertebrates respond to the prevailing conditions. While some spiders overwinter in the safely of an egg sac, or as tiny spiderlings on leaf litter and tree trunks, others winter as grown young or adults. In warm conditions, some of these species overwintering as grown spiders continue to be active through the winter months, hunting or looking for mates. This post was prompted by a silky, silvery mouse spider Scotophaeus, that I found on the kitchen ceiling in the morning (above). So, I decided to investigate which other spiders were about inside and outside of the house. All the photos taken this morning.

Pholcus phalangioides.

The Pholcus spiders in my outside toilet, which is not heated, have been much more active than it is usual in winter. Pholcus adopts a curious flat position in cold conditions, but a large individual has been changing corners and looks gravid, or indeed very well fed.

Amaurobius similis with centipede prey

 In a crack at the bottom of the toilet door lives an Amaurobius similis. A couple of weeks ago I watched as a large springtail, Orchesella villosa, tripped one of her woolly silk lines. The spider sprung out like lightning out of her retreat, but the springtail, making use of its wonderful jumping abilities, escaped unharmed. Today the spider was luckier. I noticed she was out, which is unusual, and looking closer I saw she was busy with prey: a centipede, likely Cryptops hortensis.
What other spiders are out and about?
Inside the kitchen window, a mid-size garden orb-weaver Araneus diadematus, hung from her web. They occasionally wander inside and live on small plant midges or drosophila from the fruit bowl. Females have occasionally reached full size inside the house and attracted males.

A poor shot of an Araneus diadematus inside the house.

Zygiella x-notata legs visible touching its web.

On the sheltered top corners of windowsills you might find Zygiella x-notata, the missing sector spider, in a silky retreat, often next of her egg sacs and the empty wrapping, one of her front legs touching the guide thread to the center of her web. At night she comes out and sits in the middle of her web. They are active regardless the weather, building their new webs early in the morning even in hard frost.

Wandering male lace weavers

In the last week I have found two different males Amaurobius similis wandering, one in the porch and the other in the house. Note the different abdominal pattern in the photos below, especially the dark blotches surrounding the cardiac mark (the midline elongated area over the abdomen). In this species, mature males are most likely to be found between September and November, and they abandon their webs in search of the female retreats. I released them both after taking their photo paying especial attention to the palp (above), which is diagnostic and separates this species from the similar one A. fenestralis. Males A. similis have an inward pointing, curved sharp projection on its palp, which in A. fenestralis is thicker and blunt.

Male 10/11/15.

Male 15/11/15.

Amaurobiidae: funnel web spiders

This family has almost 700 world species of which three are found in the UK, all from the genus Amaurobius. They are large, robust spiders who produce cribellate, 'fuzzy' silk. They are nocturnal and live most of their lives hidden in silk-lined funnels in crevices in walls, tree trunks, ivy covered walls, or under logs and stones. Funnels are easily spotted as their entrance is surrounded by a messy array of lace-like silk threads extending onto the surrounding area. The silk is bluish when freshly laid and it immediately identifies its owner before you have even seen the spider. Passing insects get tangled on the threads and the resulting vibrations alert the spider sitting in her retreat. She springs out of her retreat, localises the insect and quickly bites a leg. Once she gets a good hold, she pulls the insect into her retreat.

Carding silk
Amaurobius similis often lives inside houses, and if you know where one of her retreats is, you could witness how she combs silk with the structures on her rear legs around the entrance to the retreat. Taking time to spin a few snares around the entrance each night.

An Amaurobius similis on the entrance of her funnel on the corner of a wooden fence.

Amaurobius female carding silk.

Eggs and egg sac guarding
Males mature in the autumn, when they wander in search of mature females (the top shot shows a male Amaurobius ferox, which tends to mature at the end of winter). When they find a female's web, they drum on to the threads with their abdomen and palps to signal his approach. Mating is a very swift affair.  Females lay their eggs in a silk cell on her retreat and sits by them.

Amaurobius sp. guarding her egg sac

Matriphagy
The female's care does not end with the guarding of the eggs in Amaurobius. When the spiderlings hatch, she opens the egg sac to facilitate their emergence. They she will sit by them and eventually produce a second batch of immature eggs, which the spiderlings will devour. This first meal substantially increases spiderling survival rates. She does not end her care them, as just before she dies, she collects the spiderlings under her body encouraging them to climb over her and feed on her body. Watch this video documenting this fascinating spider's maternal behaviour:

Amaurobius ferox male showing his remarkable palps, which appear to be holding white marbles.

A female Amaurobius female on her blue silk threads. 

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.

A spider safari

Today for 30 days wild we did a spider safari. Any day is as good as the next for spiders if you ask me, but I am aware there are many people either fearful or wary of spiders. If you are in either of those categories, thank you for reading on, I hope that at the end of the post you look at them for the wonderful and diverse group they are and by understanding them better you might keep a certain level of respect for them, but enjoy them more. All the photos were taken today.
 My daughter found a large cluster of Garden Orb Spider Araneus diadematus spiderlings in between two pots (above). These spiderlings balls are now everywhere (even on my car!). Once they hatch from their silky cocoon, they will stay in a tight ball for a few days in a communal web. After they moult they will disperse to make their individual webs and start catching tiny insects, mostly aphids.
 There are two age groups of Araneus in the garden now. The tiny newborn spiderlings and the year old spiders which have survived the winter and are not mature. This large male has built its web in a flowering sage with is always busy with insects.

Male Araneus diadematus on his web.

A male Philodromus aureolus

 We also found this lovely spider crawling on a hedge, on our way back from school. Males of some crab spiders have iridescent scales on their bodies. I think this is Philodromus aureolus. After failing to take a photos where it was as it was quite mobile, I potted it to photograph at home. Shortly after I released him in the garden I found another individual on ivy, and what could possibly be the female of the same species (below). Crab spiders don't build webs, instead sitting on leaves or flowers to ambush flying insects that stop to bask or feed on the flowers.There are several common Philodromus species, and without microscopic examination of their genitals (or palps in the case of males) identification to species is not possible, which is sadly true for many species of spider.

A female Philodromus sp.

 I searched on some bare ground in the garden and didn't take long to find a wolf spider, a Pardosa, (probably amentata). Wolf spiders don't build webs either, but they move about searching for insects, although they also do quite a lot of basking on sunny spots on the ground. As they don't have a 'home' females carry their egg sacs with them attached to their abdomen, which you can see in the photo below. This photo also illustrates the maternal behaviour of spiders: many species build a cocoon for their eggs, which they attach to a dry corner, or carry the egg sacs with them, or the spiderlings (wolf spiders do this!) or even feed the spiderligs with eggs, regurgitated prey or especial eggs. The most extreme form of maternal behaviour is matriphagy, in which the mother allows the spiderlings to eat her, and eventually kill her.

Female wolf spider, Pardosa sp., with her egg sac.

 Another favourite place for spiders is the log pile. I removed a few logs and found a Blue Lace Spider, Amaurobius similis. A spider that forms a very characteristic form of carded silk and can be found on crevices on walls or trunks or on thick ivy. Amaurobius is one of the bunch of species in which females sacrifice themselves to their first batch of spiderlings, a matriphagous species.

Amaurobius similis. 

 And a few logs later a large female House Spider, Tegenaria sp. House spiders built sheet webs funnelling into corners, where they have a retreat. When potential prey lands on the sheet they come out and trap them. You can entice them to come out by spraying some water on the sheet web. If you see a large spider with long legs in the autumn running around on your living room carpet, or you find one in the bath in the morning they are likely to be a male Tegenaria. They have abandoned their retreats and go about searching for mature females to mate.

Female Tegenaria sp.

 Then it was time to go inside. I have a thriving Pholcus phalangiodes (known as Daddy Long Leg spiders) population in the house. They hang from corners in the ceiling, not moving much. This mature female, which lives under a shelf in the toilet, with her distended abdomen, looks ready to lay her eggs. She will wrap them loosely with silk and carry them in her mouth until they hatch. Then she will sit by her spiderlings for two weeks (presumably not eating anything during this time). Despite their spindly appearance, Pholcus are fearsome predators, capable of subduing much larger and stronger spiders by wrapping them in silk with their long legs.

Pholcus phalangioides, mature female.

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.

Black Lace-Weaver wanderer

 In springtime male Black Lace weaver spiders roam in search of females. This one was dangerously walking on the pavement this morning, cold and wet from the night's rain. I took some quick shots and took him home for a white background session. The male palps look like they are holding white balls, these are the characteristically white and very visible palpar organs in this species.
 Black-lace weaver females (Amaurobius ferox), as their smaller relatives Amaurobius similis, have remarkable maternal behaviours, including guarding the spiderlings, feeding them using unfertilised eggs and then finally, encouraging them to eat their own bodies (matriphagy). For a fantastic video documenting this spider's maternal behaviour see this Arkive entry.
 More info in the British Arachnological Society page.

Black Lace Weaver: the female

Not even a week after finding my first male Black Lace Weaver, Amaurobius ferox, I came across the beautiful female by the back door mat of some relatives. The previous day I had seen a very fresh dead, limp male - which now I believe had just had a fatal encounter with the female - and possibly disturbed the female from feeding on its corpse. I checked the palps and left the corpse where I found it. The following day, on the same place where I had found the dead body of the male, I spotted the female, indoors. I took more photos of her, velvety black, fresh, alert. She moved across the room in broad daylight, and fearing for her life, I took her outside to a safer place.

A view of the top of the female, showing how dark it is and the faint markings of her abdomen

Crouching by a chair leg

A 'habitat' shot

Later, I spotted the body of the male, this time wrapped in cribellate silk, its skin empty like a discarded sweet wrapper. Were both wandering in search of mates, what was she doing out in the daylight, far from her hiding hole? 

Velcro spinning spider

I found this female Amaurobius similis in the same spot in the kitchen than in January last year. I wonder if it will be the same individual or this is an ideal spot for this species. At around 11 pm, she was carding her silk using the calamistrum or comb in her rear legs (click here for close up photos of this structure). She changed position every now and then. I have posted on the beautiful blue woolly silk of Amaurobius before. In this photo the silk colour is not visible, but I liked to see the spider in action preparing and adding her silk strands around her retreat.

W.S. Bristowe, a wonderful spider watcher, described how the spider makes her 'velcro' snares in detail:

Ciniflo's [now named Amaurobius] spinning operations take place short after dark and as the spider usually stops spinning soon after the light of an electric torch is shone on her it may take a little time before her exact methods are accurately worked out. The abdomen is tilted slightly upwards and the femurs of the hind legs stand out laterally, almost at right angles. The remaining segments of one hind leg are directed backwards and inclined somewhat inwards, while those of the other leg are bent inwards at the tibia nearly at right angles in such a way as to allow the tarsal claws to clasp the other hind legat the base of the metatarsus. In this position the calamistrum, or comb, on the metatarsus of one leg is situated just behind the spinnerets. The spider remains stationary ... [while the threads] spun by the posterior pair of spinnerets are combed out by a rapid oscillation of the legs into loops and flounces. At the same time she moves in such a way as to stretch out the ribbons she has spun.

A side view of the spinning spider.

And a video showing the behaviour. I was a bit nervous of supporting the camera on the windowsill just in case I disturbed her, hence the shakiness!

More information
Bristowe, William Syer. The world of spiders. Vol. 38. London: Collins, 1958.

Drama under the barbeque

This morning, while watching the hoverflies feeding on the fennel I realised I wasn't the only one interested in them. A female digger wasp Ectemnius, was poised on a cherry leaf, attentively following the action, and at one point the spotted a suitable hoverfly victim and attempted a capture.
 In the afternoon I came across Ectemnius again. Another female inspecting potential nest holes in a bee hotel, going in and out of them.

 I decided to sit and watch the action, faintly hoping the wasp would start digging a nest. I noticed the characteristic carded silk threads of Amaurobius spiders (top shot), and thought that spiders and digger wasps must come across each other with some frequency as female wasps inspect nesting sites. Then the wasp moved to the log pile under the BBQ and walked in and out amongst the logs. She appeared to have walked onto a silk thread and a false widow spider, Steatoda bipunctata, promptly came out of her refuge. A fight ensued, the wasp trying to bite or sting the spider, the spider spreading silk on the wasp and retreating, and repeating the procedure as the wasp became more and more entangled and buzzed intermitently in her futile attempts to get herself free.

 
The commotion got an Amaurobius out of her retreat, and at some point both spiders were attacking the wasp, although the Steatoda managed to secure it and, when the wasp stopped fighting, the spider cut free the threads that attached the prey to the log, and pull her to the safety of the retreat.

Early stages of the fight

The Amaurobius' legs are visible behind the abdomen of the wasp in the shot above, while the Steatoda secures the jaws of the wasp with more threads of silk

The wasp front end is now tightly wrapped on silk, now the spider focuses on the rear end

The spider drags the wasp to her retreat

 I watched all this with amazement and struggled to get decent photos as the action happened almost behind the log. The whole sequence of events happened within 15 minutes!

The blue lace web spider

I have done a lot of bee watching this week. Several solitary bees species have emerged and males are patrolling the cherry tree, which is now blossoming. A male Red Mason bee landed to bask on the ivy that covers an east facing wall in the garden. Its legs got tangled on the silk threads of a lace web spider, Amaurobius similis. The spider quickly came out of her burrow, deep in the ivy. The bee disentangled itself before the spider got near and flew away, but the spider carried on checking, with short pulls of the web with her forelegs. There is nothing in my view better than sunlight to get a good shot. This is now my favourite Amaurobius portrait. On top of the natural light, the dark ivy background brings out the warm colours of the spider and also its beautiful blue silk.
Amaurobius produce an uncommon type of silk using a silk spinning organ called the cribellum. This special silk emerges from thousands of spigots on one or more plates instead of normal spinnerets. Each fiber is extremely thin, and the spider then cards the fibers with a series of bristles in the shape of a comb on her back legs - the calamistrum - into a woolly silk, which has properties like the woolly side of velcro. Insects provide spines that get easily tangled into this silk with no need of glue. In Amaurobius, the silk is blue when fresh, with the spider working on new threads in the night.

Do spiders find ladybirds distasteful?

 I witnessed a curious interaction today. A 7 spot ladybird was walking up a wall, when a sudden movement caught my eye. It was a large spider, a female Amaurobius similis that had dashed out of her burrow in a hole in the wall, probably alerted by the pull of one of the silk threads that radiate from her burrow. She had caught the ladybird by one leg. The ladybird struggled to free itself, but she need not fight much. After a few moments, the spider released her grip, turned round and retreated into her burrow. The spider obviously had assessed the ladybird and regarded it not suitable for a meal. I doubt it was due to the ladybird size or strength, as Amaurobius are powerful spiders, able to subdue large flying insects such as droneflies and honeybees. The other possibility is that the spider has tasted the alkaloid rich liquid that constitutes ladybirds chemical defence mechanism and that is released from their leg joints when alarmed (the 'blood reflex'). I have previously seen dead ladybirds wrapped on silk caught on the webs of two spider species (garden spiders Araneus diadematus and the false widow Steatoda bipunctata). Indeed, field surveys and experiments carried out by John Sloggett showed that A. diadematus does trap and consume ladybirds, and is apparently immune to the toxic effects of ladybird's chemical defences. In contrast, other spider species do seem to find ladybirds distasteful, so this is a strong possibility for Amaurobius.

Another view of the interaction, not as sharp, but it shows clearly how the spider's chelicerae are pulling and lifting the ladybird's front right leg.

For other spiders, however, ladybirds are not even considered a food item. Take this little wolf spider, enjoying the company of the 7 spot ladybird a few days ago. Both individuals were sunbathing next to each other most of the morning. The spider popped in and out, paying no attention whatsoever to the ladybird.

More information

Sloggett, J. (2010). Predation of ladybird beetles by the orb-web spider Araneus diadematus BioControl, 55 (5), 631-638 DOI: 10.1007/s10526-010-9291-0

More awakenings

 The early spring temperatures continued today. Ants were scouting out of their nests, sage leafhoppers were active and honeybees and droneflies enjoyed the Laurustinus. I waited until the bee and the dronefly visited the same inflorescence to take the above shot. I wonder if the Laurustinus flowers change colour when they are pollinated, in the same way as the Horse Chestnuts, white when fresh and turning red when already pollinated and stop producing nectar. 

We counted over 100 7-spot ladybirds in the garden. Some were eating aphids on the spurge.

The entrance of the burrow of a large Amaurobius spider under a garage roof. If you click to embiggen you can see the remains of a wasp a Harlequin and some wings I cannot identify, possibly from bluebottles.

A green shieldbug, Palomena prasina, on its dark winter attire came out of its overwintering refuge.

 Wolf spiders enjoyed the sun on the sunny side of the garden.