Family Araneidae
They build their orb webs at night and hide on grass stalks by day.
They are small spiders and easily recognised by their dark and light bands on the abdomin.
They have poor vision and locate their prey by sensing vibrations and tensions in the web. Prey consists mainly of flying and jumping insects.
Spiders are able to re-cycle and re-use up to 90% of their own silk by eating it and is available again for use after 30 minutes.
Info from: Spiders of the Kalahari (Ansie Dippenaar-Schoeman)