Platform Web Spiders

Unidentified platform-web spider in the back garden of my house in Hayes.  Female.  5 August 2011.

I don't usually post photos of species I can't identify, but I don't have any proper reference books for spiders so for the time being I can't name it. But I do know some things about spiders in general.

This is a platform-web spinner. They produce horizontal webs with a number of anchoring strands reaching up and down. Those that reach up also act as a trap; if some flying insect collides with a strand it will fall onto the platform, and be pounced on.

This web was low to the ground, and its inhabitants were on its underside, so I could only photograph them from underneath. You can see the female's plump abdomen, and the tips of her mandibles pointing straight at you.

Below is the male. He is thinner; he does not have to accumulate energy to produce eggs. The mandibles are more clearly visible. You can also see his large, oddly shaped pedipalps which are used during sex. The male spins a small web on which he deposits sperm. He sucks this up into his palps, and it is from these that he inserts it into the female, reaching over her body to do so. A remarkable and strange method of fertilisation.

These spiders "listen" for vibrations in the web with their feet. Look at the male. He is widespread and his feet are placed to notice vibrations from any direction. Now check out the female. Two of her feet are on key strands; she made this web, and she knows its properties. She stays in it, and the male must come to find her.

Unidentified platform-web spider in the back garden of my house in Hayes.  Male.  5 August 2011.