While picking up a dead moth from the living room floor, I noticed a spider greedily devouring it. That got me curious. . .
Jumping spiders are common throughout North America. Generally carnivorous, jumping spiders are usually found in vegetation where they lie in wait for insects upon which to prey. Their common name derives from the leaps jumping spiders make when pouncing on their victim. Before jumping, the spider secures a silk thread by which it can climb back to its perch if it misses the mark. The power for jumping comes from the jumping spider’s fourth pair of legs. Unlike grasshoppers and other jumping insects, the legs are not muscular and modified for jumping. Instead, the internal fluids of this arachnid extend into the fourth pair of legs and hydraulic pressure propels the jump.
Jumping spiders do not spin webs but rather make little silken shelters under leaves, bark or stones. They moult, build egg cases and overwinter in these little “tents”. Most active during the day and liking sunshine, jumping spiders also spend their nights in their cocoon shelters.
Jumping spiders can be recognized by the rectangular shape of their cephalothorax and the roughly rectangular shape of their head, looking face on. The arrangement of the jumping spider’s eight eyes are also characteristic. The eyes occur in three rough rows. The first “row” contains two large eyes that face forward. The next row has two very small eyes above and to the outside of the large median eyes. Finally two pair of eyes in the third row face upward and slightly forward. Jumping spiders have the best vision among invertebrates.
I believe this jumping spider is Phidippus clarus, a species whose markings are quite variable.
The pictures were taken in our Lookout CA house (Modoc County).