Jumping Spiders

The Essays of Frances Williams ~ September, 1968

Published Aug 27th 2017 in Wildlife, Phidippus, Jumping spiders

Jumping spiders are welcome residents in my home. They never build messy cobwebs; they pay their rent by eliminating the silver fish which would eat the glue from the spines of my books; they are friendly, alert, and have a personality which leads a sympathetic observer to anthropomorphism. (Anthropomorphism: ascribing human traits, to animals.)

My jumping spiders belong to the genus Phidippus. I have been unable to place them as to species. They are black, and covered with short, thick hairs. Like all spiders, their bodies have two parts, the cephalathorax and abdomen. The cephalathorax, or front portion, is high, convex, and broader than the abdomen. The top of the abdomen has a triangular white spot in the center, with two smaller white spots on the rear. The books say that males and females of jumping spiders are marked differently, but either mine are, all one sex or this species does not have sexual dimorphism. They are usually about one-half inch long, but occasionally one reaches three-quarters of an inch.

Jumping spiders are hunters, pursuing their prey or springing upon it when it comes near them. Their legs are short and stout, and they move with quick jumping movements. They move sidewise or backward with great ease, and can jump-up to six inches. When they jump, they spin a dragline so they can regain their original position by climbing up the dragline. Phidippus has very keen eyesight. Most spiders are so shortsighted that they must rely on their sense of touch to distinguish their prey from their mates. Phidippus rears up on his back legs, assuming an “on guards” position if a probing finger approaches within a foot. The Jumping spider can see its prey in the distance, creep slowly forward, then leap upon it.

When the female jumping spider is ready to lay eggs, she builds a nest. The nest is placed in a corner, the completed structure being about 1.5 inches long and oval-shaped. The nest is composed of two envelopes. The inner one contains the eggs, and there is a space large enough to contain the adult spider between the inner and outer envelopes. The outer envelope is made of very tough silk, and is so closely woven that only a shadow of the female can be seen through it. The adult spider walls herself into the nest, guarding the eggs until she dies. I have not been fortunate enough to see the spiderlings emerge from the nest. However, I began finding pin-head size jumping spiders all over the house about three weeks after one female built her nest in the corner of the ceiling in the kitchen. The almost microscopic little spiders could jump an inch and a half.

Jumping spiders belong to the family Salticidae which occurs mainly in tropical regions, although representatives of it are found in all parts of the world except in the polar regions. Kingston, a British naturalist, found a jumping spider 22,000 feet up on Mt. Everest. Several thousand species have been described, and nearly three hundred are known to occur in America north of Mexico. For the most part, they live close to the ground, in grass and weeds. When winter comes, the young spiders build a silken retreat much like the adult's egg nest, and hibernate until spring. These retreats are built on plants or under stones. Those individuals which take up residence in my house do not hibernate, but may been seen stalking their prey almost any day of the year.

Many people fear spiders because they believe that spiders are poisonous. It is true that spiders secrete poison with which they kill their prey but it does not necessarily follow that the poison that kills a fly will kill a man. It is also true that very few spiders are strong enough to puncture the skin of a human to inject poison. Anyone who enjoys walking will find much of interest if he learns something of the habits of spiders. Their webs are to be found everywhere, and these vary with each species. The habits of the hunting spiders are also fascinating to anyone who uses his powers of observation.