August in Missouri also marks the return of the orb weavers. I think of an orb weaver as a tiny conglomerate that combines an engineering firm with a chemical plant. For these are the creatures which spin huge webs each night.
Spider silk is stronger than any human engineered material, and spiders can create up to ten different kinds - though each spider makes only around five different types. The spider's body contains hundreds of silk glands, each of which can produce a single type of silk, and each of which has a separate "nozzle" on the spinneret. Some glands produce thick strands to construct the initial outer ring of the web, others produce smaller strands to make the radii, still others make the sticky silk to capture, while others make silk to bind prey, and others make silk for egg sacs.
The spider's chemical manufacturing isn't limited to silk; she also produces neurotoxic venom to kill or paralyze her prey, as well as powerful digestive liquid. Lacking a mouth and teeth, she must inject her prey with venom and digestive fluid to kill the prey, which is digested inside itself. The spider will suck the digested fluids out later.
The engineering of web construction is no less amazing, and the spider must re-engineer the complete web each day. She will weave beginning at day's end, and early the next morning will consume the entire web to recycle the silk.
But the orb weavers have to grow and develop as well as the crab spiders. Here's a tiny orb weaver.
The first shot is the butterfly bush from about five feet away. Can you spot the spider?
The second shot s taken by natural light. It's not a pretty dsay, and the sky is gray, but as you can see, the flat light and low contrast are simply enabling this spider to be less visible.
Third shot uses flash to bring out a little more detail. Note the characteristic pose, with front legs folded and extended forward. Note also the characteristic long, narrow cephalothorax; you can see the four eyes grouped on top of the thorax. There are four more obscured from sight.
This one is not developed enough to have constructed a web yet. But with luck, it won't be long.
Edited by davidearls on Aug 11, 2008 at 03:41 PM GMT
