Stretch spider portrait

I found this female stretch spider, Tetragnatha, in the garden this evening. I remembered that they have lovely faces and I gave it a try on the white bowl aiming for a frontal shot. They have their eyes in two rows, the bottom central pair facing forward. The face shot also allows to see its enormous fangs. After a short session in the bowl, I returned the spider to her leaf and she rapidly climbed to her retreat.

The resting position of Tetragnatha on a leaf.

Tetragnathidae: stretch spiders or long-jawed orb weavers

This is a large world family, with only 14 British species. Most build orb webs and sit in the middle, instead of having a signal thread and a retreat as in typical orb weavers (Araneae). Tetragnatha are very elongated spiders with slender bodies and long legs, except the third pair, which is short and often hold the spider to stems and grasses while the remaining pairs are stretched forward and back. When disturbed, they run out of their web and stretch themselves along leaves or stems. Some species have a preference for damp places and one of them Meta menardi, lives in caves and other dark places. One of the genera, Pachygnatha, does not build webs when adults.

The locking of the jaws

Males and females have extremely long chelicers furnished with internal spines. Males have two pair of additional large and spines protruding from the inside and outside of his chelicers. These spines lock the female's chelicers open during mating. The male's palps are also very long. For a video of a mating pair of Tetragnatha click here and for a fantastic post by Catherine Scott with observations of mating and male competition click here.

Tetragnatha extensa on resting posture on a leaf over the pond water.

Tetragnatha extensa turning on a leaf allowing to see her chelicers.

Tetragnatha extensa on her web over a pond

Female Metellina sp. on her web. Metellina females are quite plump and don't have particularly long legs.

Male Metellina guarding a female's web. Unlike the female, he is slender and looks more similar to Tetragnatha. He will wait until a female catches an insect to mate. For more information on this species mating strategy see this post at Bugblog.

Stretch spider identity revealed

There is a population of Stretch spiders Tetragnatha sp., on the wildlife garden. On Saturday I popped in with my youngest daughter and there was an adult female by the pond, sitting in the centre of her web, which was almost horizontal, about 20 cm from the surface of the water. She noticed the disturbance and retreated to one end of her web. Fortunately still exposing her underside so I could photograph the areas that make it possible to identify the species: the sternum with a paler centre and the epigyne or genital opening. Matt Prince and Dr Richard Pearce on Twitter confirmed her ID as Tetragnatha extensa, a species likely to be associated to water.

A garden stretch spider!

It has been so pleasant today, warm and still, with high clouds. I had planned to do a little evening gardening and I was about to start trimming the olive tree when I noticed a busy spider web spinning. Wait, a stretch spider, Tetragnatha, a new spider for the garden! I rushed back home to fetch the camera and took some photos. I think it is a female, possibly adult. Her yellow abdominal stripe glowing with the flash. I couldn't bring myself to capture it for ID as I would have surely destroyed her web and spoiled her night hunt, so I might do tomorrow. I will update the post if I find out what species she is.

A Stretch spider by the pond

I spent some time in the wildlife garden this morning looking and photographing pirate wolf spiders (post to follow) and watching pond skaters in the pond. I had noticed a pair of legs coming from under a yellow flag leaf, hugging it and I decided to inspect. As I turned the leaf I spied a large, wonderful female stretch spider of the genus Tetragnatha. The spider had its front and rear legs stretched to the front and rear, and held onto the leaf with her middle legs. She walked up and down the leaf, rearranging her silk threads, which I had possibly dislodged. She was quite a large sized and very colourful spider, with yellow and red stripes on her elongated abdomen, it looked so exotic and tropical!
  Out of the six British species of Tetragnatha, two are larger and more common and one of them associates with water, T. extensa, although detailed genital examination is needed for a secure identification.
 Tetragnatha have very large jaws, and the males using their modified jaws to lock the female's in place - and keep out of danger - when mating.
 You can see the folded fangs in this shot

And this is a scanned figure from Bristowe's The World of Spiders (1958), drawn by Arthur Smith, demonstrating the locking mechanism (male at the bottom)

I took this shot to give you an idea of the size of the spider

For a wonderful account of the mating behaviour and natural history of these spiders, go to the Spiderbytes blog.