''Phidippus johnsoni'', the red-backed jumping spider or Johnson jumping spider, is one of the largest and most commonly encountered

jumping spider Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. , this family contained over 600 species description, described genus, genera and over 6,000 described species, making it the largest family of spide ...

s of western North America. It is not to be confused with the unrelated and highly venomous

redback spider The redback spider (''Latrodectus hasselti''), also known as the Australian black widow, is a species of highly venomous spider believed to originate in Australia, but which is now found in Southeast Asia and New Zealand. It has also been fo ...

(''Latrodectus hasselti'').

Description

Adults tend to be about a centimeter in length. Both sexes have a bright red

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

; the female has an additional black central stripe. The

chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...

of both sexes are of a shining

teal alt=American teal duck (male), Green-winged teal (male) Teal is a greenish-blue color. Its name comes from that of a bird—the Eurasian teal (''Anas crecca'')—which presents a similarly colored stripe on its head. The word is often used ...

color. The rest of the body is mostly black. It is one of the species of jumping spiders that are mimics of mutillid wasps in the genus '' Dasymutilla'' (commonly known as "velvet ants"); several species of these wasps are similar in size and coloration, and possess a very painful sting.

Distribution

The distribution of ''P. johnsoni'' is bounded by the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

, the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, northern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, and southern

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. It occurs from sea level to

tree line The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

, occupying relatively dry habitats such as coastal dunes or oak woodlands. Between two and thirty redback jumping spiders per 1,000 m² were found during a study in 1976. In 2012, NASA sent an individual of this species into space.

Habits

This species constructs conspicuous tubular silken nests under rocks and wood on the ground and sometimes grape vines. They remain inside these at night and during bad weather. Molting, egg laying and sometimes courtship and mating occur inside these nests. Most of the time they feed on prey about half their own size, but a range from to about has been observed. Although found to feed on a wide variety of insects (e.g.,

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...

, bugs and

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

caterpillars and adults), they also prey heavily on spiders. Cannibalism does occur from time to time, in the form of females feeding on males.

References

*Peckham, G. W. & E. G. Peckham (1883). Descriptions of new or little known spiders of the family Attidae from various parts of the United States of North America. Milwaukee, pp. 1–35. *Jackson, R.R. (1977). Prey of the jumping spider ''Phidippus johnsoni'' (Araneae: Salticidae). ''J. Arachnol''. 5:145-149
PDF
*Jackson, R.R. (1978). The life history of ''Phidippus johnsoni'' (Araneae: Salticidae). ''J. Arachnol''. 6:1-29
PDF

External links

(with pictures of mating dance)
High-speed photos of Phidippus johnsoni leaping
{{Taxonbar, from=Q675345 Spiders described in 1883 Salticidae Spiders of North America