''Phidippus johnsoni'', the red-backed jumping spider, is one of the largest and most commonly encountered
jumping spiders of western North America. It is not to be confused with the unrelated and highly venomous
redback spider (''Latrodectus hasselti'').
Description
Adults tend to be about a centimeter in length. Both sexes have a bright red
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
; the female has an additional black central stripe. The
chelicerae of both sexes are of a shining
teal
alt=American teal duck (male), Green-winged teal (male)
Teal is a greenish-blue colour. Its name comes from that of a bird — the Eurasian teal (''Anas crecca'') — which presents a similarly coloured stripe on its head. The word is ofte ...
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
''Dasymutilla'' is a wasp genus belonging to the family Mutillidae. Their larvae are external parasites to various types of ground-nesting Hymenoptera. Members of this genus are highly variable in sting intensity, ranging from a 1 ('' D. the ...
'' (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 (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...
, the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
, northern
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, and southern
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. It occurs from sea level to
tree line
The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowp ...
, occupying relatively dry habitats such as coastal dunes or oak woodlands. Between two and thirty redback jumping spiders per 1,000 m
2 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
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...
nests under rocks and wood on the ground and sometimes grape vines. They remain inside these at night and during bad weather.
Molting
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
, 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,
bugs
Bugs may refer to:
* Plural of bug
Arts, entertainment and media Fictional characters
* Bugs Bunny, a character
* Bugs Meany, a character in the ''Encyclopedia Brown'' books
Films
* ''Bugs'' (2003 film), a science-fiction-horror film
* ''Bugs ...
and
moth
Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
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)
{{Taxonbar, from=Q675345
Spiders described in 1883
Salticidae
Spiders of North America