Thursday, September 15, 2011

Spider Anatomy

Here is the wolf spider that found dead in my basement. Who knows how it died but I saved it and took these photos. You can see the eye arrangement of a row of one small eye, two large and one small on the top row and the 4 small on the bottom row. The ones for main vision are the two larger ones as you might expect and the smaller ones called ocelli are used mostly for sensing light and dark. I definately get the sense that this spider could see me very well if it were still alive. Wolf Spiders activelly search for prey and need the good eyesight. Jumping Spiders have the best eyesight, even better than dragonflies.

Turning the carcus over you can see the fangs (Chelicerae) which are very large. They are like needles that pierce the prey and inject venom for the final kill and turns the insides to liquid. Spiders' guts are too thin to take in solid food, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, since they do not have true jaws. The two furry short looking feet on each side are pedipalps.

Here is another view of the pedipalps and the female genital opening, known as the epigyne on the underside of her body.

Below is a good view of the spineretts that contain the many spigots, each of which is connected to one silk gland.

Hope you enjoyed this simplied spider anatomy. I only mentioned a few of the parts that are unique to spiders, I figured everyone would recognize the legs and body parts.


Cindy said...

Very cool. Dead bugs give us chance to have a good close up look at something without worrying if it will bite or try to escape. How big was this spider?

Jacqueline Donnelly said...

Thanks for the lesson in spider parts. I've always wanted a closer look, but didn't want to handle a live spider, nor to kill one.

squirrel said...

Cindy and Woodswalker, I was very lucky to find a dead one. It is hard to say how big the spider is because it is all curled up. The main body is just a tad over an inch, fangs to spinerets. I'm not afraid of spiders but I don't like to touch them either, even this dead one is creepy furry to the touch.

laurak/ForestWalkArt :) said...

very cool close up shots and so much info i didn't know! thanks!!