Thursday, June 25, 2015

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.

  

10 comments:

  1. Thanks for this, I'll have another look at one I Identified as Tibellus oblongus. They look very similar

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    1. I struggle with spider IDs Adrian

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    2. I struggle with IDs full stop.

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    1. ..... Mind the spiders don't bite! Hope your mum is on the road to recovery, and that you are looking after yourself too.

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  3. Now you see, I always thought that was a type of wolf spider! You see hundreds in the fields round here, with the yellow stripe.

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    1. I'd never paid much attention to them until recently Simon

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