Jumping Spider

Monday, September 19, 2011

Natural History Notes
by Bob Thomas

It’s difficult not to love to watch Jumping Spiders, members of the family Salticidae. These little guys obviously have personality. They are very alert, and seem to spring about with great excitement.

In fact, they have the best vision of all spiders. Their eyes are arranged so that they have two very large eyes pointing forward, giving them good binocular vision. They can see 4-8 inches, and they catch their prey by approaching, then jumping on it - a distance often many times their own length.

Since they have such good vision, the are often brightly colored and are active during day light. Their mating rituals require good vision, as well. The males usually have a brightly colored first pair of legs, which they wave to the female. If she is receptive, she may use one or two sets of brightly colored legs to reply.

Males often have brightly contrasting pedipalps (leg-like appendages located between the jaws and first pair of legs) that they move constantly to communicate with others of its species. One local common small species has white pedipalps that continually move in circles.

Jumping Spiders are usually squatty bodied and very hairy, often looking much like little tarantulas. A common local species is Phidippus audax. Its males are black with white spots here and there, and the pedipalps are iridescent aqua. Some other species are bright red, others are skinny or green. The most unusual species look just like ants, which allows them to infiltrate ant parties and eat the ants.

The next time you see a Jumping Spider bouncing about, just sit and admire. If only we could move like that.