jumping spider
How many species of jumping spiders are there, and where are they found?
Are jumping spiders dangerous?
jumping spider, (family Salticidae), any of more than 6,000 species of spiders (order Araneae) known for their ability to jump and pounce upon their prey. The largest and most diverse of the spider families, jumping spiders are very common in the tropics, but some live in northern and even Arctic regions. Noted for their intelligence and remarkable eyesight, they are cunning and agile ambush hunters and do not build webs as snares. Their bite is not medically significant to humans and causes only a mild reaction in most people.
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Salticidae
See also list of spiders.
Physical description
Jumping spiders range in size from 2 to 22 mm (0.08 to 0.87 inch), although most are small to medium size. Like all spiders, jumping spiders have six pairs of appendages. The first pair, called the chelicerae, constitute the jaws. Each chelicera ends in a fang containing the opening of a venom gland. The second pair of appendages, the pedipalps, are modified in the males of all adult spiders to carry sperm. In many species the pedipalps are covered in hairs and often resemble short legs near the mouth; they are also used to handle food and function as sense organs. The eight legs of most jumping spiders have an internal hydraulic system that can propel them many times the length of their bodies. Though there are a few species that have hairy bodies, most species have few hairs (setae). The body is often brightly colored or strikingly patterned, especially that of the male.
Jumping spiders have eight eyes and excellent vision that can perceive the full spectrum of color and discern fine details. The two large, forward-facing eyes have spherical lenses, internal focusing mechanisms, and four-tiered retinas that act like a telescope, making distant objects appear closer. Two of the other six eyes are beside the main eyes, while the other four are around the crest of the head and serve as motion detectors.
Jumping spiders are usually strongly sexually dimorphic, and females are typically larger than the males. Males and females of the species Phintella vittata are able to detect ultraviolet light from the UVB band (315–280 nm) and have specialized surfaces on their bodies to reflect it. The reflection of UVB radiation by males during courtship has been shown to enhance their ability to attract females. Peacock spiders (genus Maratus) are also noted for the males’ colorful and iridescent abdomens, which they use in elaborate mating rituals.
Natural history
Jumping spiders are active during the day in sunny areas. At night they hide in closely woven silk nests under bark, stones, or leaves. However, not all species make enclosed shelters. Most jumping spiders are solitary, and—with a few exceptions, such as certain species that mimic ants and when adult males cohabitate with females—jumping spiders do not nest together. In some cases a male will build a nest near the nest of an immature female of the same species and will mate with the female once she matures.