Scorpions Spiders Mites and Ticks: Arachnida

Physical characteristics: The stout-bodied adult zebra jumping spider ranges in size from 0.20 to 0.32 inches (5.1 to 8.1 millimeters). The two body regions are not segmented and are attached to each other by a narrow waist. The body is black with white hairs that form stripes on the abdomen. The eight legs are rather short and covered with sensory hairs. The fangs are large and usually hidden by the leglike mouthparts. Males are similar in appearance to females, but they have larger fangs, a darker body, and brightly colored bristly brushes on their pedipalps. Their eight eyes are arranged in three rows of four, two, and two. Jumping spiders have binocular vision: two of their eight eyes are very large and pointed directly forward, making them capable of focusing on a distant object. Binocular vision allows jumping spiders to accurately determine the distance of prey or another object. The large eyes of jumping spiders are capable of slight movement to adjust focus or to scan the scene without having to change body position. Their legs are not especially enlarged for jumping.

The head of a zebra jumping spider showing six of its eight eyes (rounded bumps, upper center), one large pair at the front, and smaller eyes on the side. Below the eyes are the two large chelicerae which carry teeth for biting prey. (©Andrew Syred/Photo Researchers, Inc. Reproduced by permission.)

Geographic range: The zebra jumping spider ranges throughout the Northern Hemisphere, including most of Europe and the United States.

Habitat: This species is common in gardens, on rocks, stones, flowers, plant foliage, grass, and occasionally on trees. They are often found on vertical surfaces, such as walls, fences, decks, patios, and doorways.

Diet: They eat mostly small insects and spiders.

Behavior and reproduction: Jumping spiders jump more than they walk, and they can do so forward, sideways, and backward with equal ease and speed of movement. They do not use webs to capture their food but instead actively hunt their prey throughout the day. These spiders can catch prey up to twice their own body length, spotting them as far away as 8 feet (2.4 meters). They slowly stalk and pounce upon their prey from as far away as 6 inches (15.2 centimeters). Before jumping, the spider plays out a strand of silk and attaches it to the ground or to a branch or leaf as a safety line. Using its fangs, the spider delivers both venom and digestive chemicals. The prey is then chewed up with the spider's powerful mouthparts, and its body fluids are sucked into the spider's mouth.

Jumping spiders also build a silken cocoon or retreat into crevices, under stones and bark, or on foliage. Retreats are used as hiding places at night or shelters for molting, feeding, protecting young, and hibernation (high-bur-NAY-shun), a period of inactivity during the winter.

Before mating, males must first transfer sperm to special chambers on their leglike mouthparts. Males then court females with an elaborate and colorful display of leg waving. This dance is intended, in part, to identify the male as a potential mate for the female and not a meal. If she is willing, the male attempts to deposit the sperm into an opening underneath the female's abdomen. Females lay their eggs in silken shelters and guard them until they hatch and molt for the second time. Zebra jumping spiders mature in late spring or summer and live for about one year.

Zebra jumping spiders and people: Although the species is considered a nuisance around homes and buildings, these spiders are harmless to humans and probably eat many insects that are considered pests.

Conservation status: This species is not endangered or threatened. ∎