Musings and photos of wild and everyday life

Posts tagged “Silk

Spider Behaviour

Male Spider Tetragnatha extensa cocooning prey in web

There’s been a bit of a gap since the last post – maybe a sign of a good Summer?

Delicate touch - Spider Tetragnatha extensa on web in flowers

Delicate touch – Spider Tetragnatha extensa on web in flowers

Those of you squeamish about Arachnids should maybe wait a bit longer – this is the second part of a Spider feature, dealing more with behaviour.  The previous post can be found here –  Spiders in Ireland.

The first thing we think of regarding spiders is Webs.  Apart from having 8 legs and numerous eyes, this is a very defining deature.  The first picture shows the delicte, sure touch of the spider as well as the strength of the silk lines it weaves.

Spider's Web in frost

Spider’s Web in frost

Raindrops on tiny web

Raindrops on tiny web

Sometimes webs are hard to see – they are used to trap flies afterall – but frost, rain and morning dew makes them very visible.

Then the brilliant structures and their number, can be admired by all.

Dew-covered Webs on bush

Dew-covered Webs on bush

Garden spider - Araneus diadematus underside showing spinners

Female Garden spider – Araneus diadematus underside showing spinners

Spiders have spinners under their rear (see picture and also Garden Spider showing spinners), from where tough silk emerges quite rapidly.

In fact spiders can produce different grades of fibres for different uses – web, temporary scaffold for making web, wrapping prey, cocoons etc – and use different glues.
Garden Spider in web - waiting, feeling

Male Garden Spider in web – waiting, feeling

Spider Meta segmentata female dragging cranefly in web

Spider Meta segmentata female dragging cranefly in web

Spiders wait quietly and still on their webs  with their legs on a number of lines, or at the edge of a web, perhaps under a leaf, but touching a main line, waiting for vibrattions that tell them some prey is struggling with the sticky web.  However spiders themselves are able to traverse the web very quickly.  This seems to be due to a number of factors:-

  1. spiders know where the sticky strands are
  2. spiders have an oily substance on their legs which resists sticking
  3. they walk in a way that minimises the contact between the glue drops and the tiny hairs on their legs and
  4. they have a third claw that seems to work with the flexible hairs to grasp the thread and release it!
Fly caught by spider- linyphiidae

Fly caught by spider- linyphiidae

Prey stuck in a web, is usually doomed unless large and powerful enough to free itself. The resident spider usually approaches quite quickly and ends the struggle with a poisonous bite.

Male Spider Tetragnatha extensa cocooning prey in web

Male Spider Tetragnatha extensa cocooning prey in web

Generally the spider then cocoons its prey using more sticky silk thread – dinner for later.

 

Although it seems out of character, some spiders do not build webs.  Hunter spiders (Hunter Spider), for example, use speed to grab and bite their prey.

 

Spider in web Lough Dan

Spider in web Lough Dan

Another use for spider silk is to make funnels and nests.

Wolf Spider with egg sac

Wolf Spider with egg sac

Spider Tetragnatha extensa on stem

Spider Tetragnatha extensa on stem

Finally, spider silk is used to make a sac to carry its eggs.

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Spiders are good at hiding, whether it is in the shadow under leaves or in the open, staying still.

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This is aided by aligning their legs with the foliage …

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or by looking un-spider-like and staying still.

Harvestman on house wall

Harvestman on house wall