19-May Webs, Wool & Wild Rituals

As spring is when most spiders hatch it is a good month to find wolf, crab, running crab, ground, tube-web, sac-web and mesh-web spiders. Wolf spiders belong to the family Lycasidae. They tend to be the large, agile, robust spiders we often see in our homes. When looked at closely they have six rather than the usual eight eyes of other spiders. Four small eyes are usually found at the front with two larger, more noticeable eyes behind them. Small, active, ground-living Pardosa spp. are typical e.g. Pardosa lugubris which can be so numerous in woods they can sometimes be heard running across the leaf litter. Alopecosa pulverulenta is a larger example and is our nearest contender in London to be called a tarantula. A tarantula is not an actual species but is the name generally used to describe large dangerous-looking tropical spiders.

The name was given to a wolf spider Lycosa tarantula found near Taranto in Italy. It was believed that if you were bitten by this spider you entered a state of deep melancholy that could only be cured by excessive dancing.

The dance became known as the tarantella. Although small (10 mm) our tarantula, which is usually dark brown with a band along its back, is still impressive. It can be found on bare open ground on Hampstead heath.

Crab or Flower spiders belong to the family Thomisidae. They are hunting spiders with no webs preferring to wait patiently in flowers using a combination of camouflage and ambush to catch their prey. When we first notice them in a flower they tend to open their large crab-like legs as if to attack before scuttling away sideways again like a crab. Generally they tend to be more colourful and slower than other spiders but have a powerful bite sometimes quite capable of paralysing a butterfly or bee almost instantly. One common small brown species found in gardens is Xysticus cristatus. The male is known to spend up to an hour tying down the females securely in silk before mating with her. This is believed to just prevent her from eating him. Running crab spiders are in a different family (Philodromidae). They are often brown or black with flatter, slimmer bodies and legs of unequal length. The males of one species Philodromus aureolus occasionally get noticed in bushes and trees due to their purple and green iridescence. Tibellus oblongus is another striking creamy-brown species. It has a dark stripe down its back and is sometimes seen stretched out lengthways on grass blades. As their name suggests running crab spiders are fast-moving and often even avoid capture by humans.

There are many species of ground spiders (Gnaphosidae). They are often greyish-brown or black sturdy-looking spiders with pointed abdomens and tiny pearly eyes. They hunt at night and tend to spend their days in silken cells under stones which is where we often find them. The Mouse spider Drassodes lapidosus is one example, so-called because of the colour of its abdomen. It is one of the largest spiders you are likely to encounter in London, the females sometimes reaching 2 cms in length. It is best to leave well alone if discovered under a stone guarding its egg sac in its silken cell.

Other families this month may be identified by their webs e.g. the tube-web spiders (Segestriidae). Their webs are tube-shaped with the spider usually remaining well hidden at the far end of the tube. At its entrance there are some radiating lines of silk which may be attached to the spider’s legs. Any movement of these “fishing line” threads can result in the dramatic appearance of what seems like far too large a spider the tube could ever accommodate. The green fanged tube-web spider Segestria florentina is likely to be the most impressive we ever come across. It is black with metallic green fangs. Females can reach 22 mm in length and can inflict a bite which remains painful for a few hours. S. senoculata, the snake-back spider is much more likely to be seen. Its webs are constructed in crevices in walls and among rocks. If the radiating threads are touched with the tip of a grass blade this spider is often easily coaxed out revealing its snake-like markings. Two other families that may be identified by their webs are the sac-web spiders (Clubionoidea) and the mesh-web spiders (Dictynidae). The sac-web spiders are often brown, medium-sized with no marking but rows of tiny pearly eyes.

Their webs are sac-shaped but in this case the sac is suspended in foliage often near the ends of branches. Clubiona corticalis is one common example fond on heaths, marshes, under bark and even around houses. It is easier than most to identify being a reddish-brown with distinctive chevron markings on its yellow-brown abdomen. The male also has noticeably large bulbous palps. Mesh webs are more like the disorganised tangle of silk you tend to see in horror films. Mesh-web spiders (Dictynidae) build smaller versions among the upper branches of dead vegetation and support them with “guy ropes”. The Common mesh-weaver Dictyna arundinacea is probably the most likely to be seen in among the branches of gorse bushes and perhaps heather. It is only small (3 mm) but helpfully is partially covered in coarse white hairs.

Caterpillars

A larger caterpillar that takes a bit of finding is the Drinker (75 mm). It is famous for its habit of taking a drink from dew drops. Although now rare it may still be worth looking on its favourite food plant Cocksfoot in places such as Deptford marshes. Its caterpillars are similar, having orange-red lines and reddish-brown hairs but it also has a distinctive erect tuft of black hairs on its back.

A caterpillar getting more common in gardens is that of the brightly coloured Garden tiger moth. Its larva (60 mm) is one of the “woolly bear” caterpillars thickly covered in this case with long black hairs tipped in grey. It is best not to touch these hairy caterpillars as their hairs can often cause skin rashes.

For sheer size and excitement that most impressive caterpillar you are ever likely to encounter in London is that of the goat moth. It can reach an astonishing 10 cms in length. It is purplish-red with orange sides, a shiny black head and has a distinct smell of goats. Like a number of other caterpillars we tend not to see it as when it hatches from an egg it bores straight into wood. It feeds on the heartwood of oak, ash and poplar trees and does so for as long as four years, gradually increasing in size before pupating. We only really ever get a chance to see it when old wood is accidentally split or broken open in some way.

It is still a little early for most of our butterfly larvae. Fritillary caterpillars are always worth looking for on violets in places such as Chapel Bank. Skippers, gatekeepers, ringlets and even marbled white caterpillars will be feeding on coarse grasses in places such as Riddlesdown. In oak woodland e.g. Wimbledon Common, purple hairstreak caterpillars will be feeding on oak leaves and on Denbies hillside, chalkhill blue caterpillars on bird’sfoot trefoil.