Nursery web spider

 The rough grassland on the old Brancepeth  colliery site, never grazed or mowed, is perfect habitat for the nursery web spider Pisaura mirabilis. This female had recently enclosed her egg cocoon inside a silken tent woven around grass stems - a nursery where the vulnerable spiderlings can hatch and grow in safety.

Over 250 years ago, the Swedish taxonomist Carl Alexander Clerck gave this species the scientific name Pisaura mirabilis, the marvellous Pisaura. Its fraught courtship ritual has been a source of wonder for arachnologists ever since. Males pacify females, which are notoriously prone to cannibalism, with the gift of a fly wrapped in silk. The larger the fly, the longer it will take to unwrap and eat, extending the opportunity to copulate before her hunger turns to aggression. So, there is a premium on males who are good hunters, though deceitful suitors sometimes wrap and present small twig fragments, risking death mid-copulation when she uncovers the fraudulent offering.

If she does accept his advances she'll eventually produce a ball of eggs wrapped in white silk that she carries in her jaws, slung under her body, until they are almost ready to hatch. The egg cocoon is so large that she is forced to walk around on tip-toe, to keep it clear of the ground.

 These pictures show what happens next - a remarkable example of spider maternal instinct. Her eggs have matured and the grasses have grown tall, so she climbed to the top and bound a few together with silk. Then in the space below she wove a tent, deposited her eggs inside, nibbling through the cocoon so that the spiderlings could hatch and then finally sealed them inside their silken nursery. 

Now, she’ll stand guard until they grow large enough to bite their way out of their nursery and take their first steps into the outside world. In the photographs below you can see her yellow egg cocoon, safe inside the nursery she has woven, with spiderlings beginning to hatch.

Nursery web spider

Although some spiders have a fearsome reputation, there’s no denying that others have endearing qualities – and none more so than the nursery web spider Pisaura mirabilis, one of our larger native species, growing up to about an inch long. It's quite common in our region in grassy places, where it spends much of the time hunting insects on the ground or sunbathing on leaves. 

Its peculiar way of resting with its front two pairs of legs held close together, so that at first glance it appears to have only six rather than eight legs, makes it easily recognisable.

The one in the pictures below lives in the garden of my eldest son and his partner, near Blaydon.

 When the time for courtship arrives in early summer the male spider catches a fly, wraps it in silk and presents it as a gift to a potential mate. Sometimes, if he can’t catch a fly, he’ll present her with a gift-wrapped piece of debris instead but it seems that the size of his gift, rather than its quality, is the crucial factor in determining whether she’ll choose him as a mate.

It's the thought that counts ...... as any bloke will tell you if he's forgotten his wedding anniversary then bought his wife a last-minute bunch of flowers in a petrol station.

If she does accept his advances she'll eventually produce a ball of eggs wrapped in white silk that she carries in her jaws, slung under her body, until they are almost ready to hatch. The cocoon is so large that she is forced to walk around on tiptoe, to keep it clear of the ground.

What happens next is a remarkable example of spider maternal instinct. By the time that her eggs have matured the grasses have grown tall and she climbs to the top and binds several together with silk. Then in the space below she weaves a tent, deposits her eggs inside, nibbles through the cocoon so that the spiderlings can hatch and then finally seals them inside their silken nursery. She’ll stand guard while they grow large enough to take their first steps into the outside world. 

This particular spider is unusual in that it has recently lost its right front leg and is regenerating a new one - in the picture above it's the dark-coloured leg at the bottom of the picture.

You can see the new leg, almost black and at 8 o'clock, in this closer image. Spiders can regenerate lost limbs will they are still growing and still moulting their exoskeleton, but once they reach their final moult at maturity they can't replace lost legs.

  

Nursery web spider

My son and his partner found this very fine nursery web spider Pisaura mirabilis in their house yesterday. These rather fearsome-looking arachnids have the endearing (?) habit of catching flies, wrapping them in silk and presenting them to potential mates. The females carry the eggs around with them underneath their body until they are almost ready to hatch, then spin a nursery web over a clump of vegetation and deposits the cocoon of eggs inside, where the young can hatch and develop in relative safety.

This individual has lost a leg on the right side of its body. Young spiders can generally regenerate lost legs during moulting if the injury occurs early in their life but this is a mature specimen, so it's destined to be a seven-legged spider for the rest of its life.