Phidippus johnsoni
Encyclopedia
The red-backed jumping spider (Phidippus johnsoni) is one of the largest and most commonly encountered jumping spider
s of western North America
. It is not to be confused with the unrelated and highly venomous redback spider (Latrodectus hasselti). When threatened, the redbacked jumping spider can inflict a quite painful bite in self defense, but with no serious medical consequences.
Both sexes have a bright red abdomen
; the female has in addition a black central stripe. The chelicerae
of both sexes are of a shining teal
color. The rest of the body is mostly black. It is one of the species of jumping spiders which 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.
, the Pacific Ocean
, northern Mexico
and southern Canada
. It occurs from sea level to tree line, 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.
This species has been introduced to New Zealand
with grape
s.
In November 2011 a female was found in a British supermarket amongst grapes from Brazil.
nests under rocks and wood on the ground. 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 2 mm to about 1 cm has been observed. Although found to feed on a wide variety of insects (e.g., flies
, bugs
and moth
caterpillars and adults), they also prey heavily on spiders. Cannibalism does occur from time to time, in the form of females feeding on males.
Jumping spider
The jumping spider family contains more than 500 described genera and about 5,000 described species, making it the largest family of spiders with about 13% of all species. Jumping spiders have some of the best vision among invertebrates and use it in courtship, hunting and navigation...
s of western North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. It is not to be confused with the unrelated and highly venomous redback spider (Latrodectus hasselti). When threatened, the redbacked jumping spider can inflict a quite painful bite in self defense, but with no serious medical consequences.
Description
Adults tend to be about a centimeter in length.Both sexes have a bright red abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
; the female has in addition a black central stripe. The chelicerae
Chelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
of both sexes are of a shining teal
Teal (color)
Teal is a medium blue-green color. It is named after the Common Teal, a member of the duck family, whose eyes are surrounded by the color.Teal is one of the initial group of 16 HTML/CSS web colors formulated in 1987, shown below....
color. The rest of the body is mostly black. It is one of the species of jumping spiders which are mimics of mutillid wasps
Mutillidae
Mutillidae are a family of more than 3,000 species of wasp whose wingless females resemble ants. Their common name velvet ant refers to their dense pile of hair which most often is bright scarlet or orange but may also be black, white, silver, or gold. Their bright colours serve as aposematic signals...
in the genus Dasymutilla
Dasymutilla
The genus Dasymutilla belongs to the Mutillidae family. The females of the genus are well known for their painful sting, which is where many gain their common name, Cow Killer. The female is wingless and often resemble large ants while the males still retain their wings. The larva of 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 PlainsGreat Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
, the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. It occurs from sea level to tree line, 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.
This species has been introduced to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
with grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
s.
In November 2011 a female was found in a British supermarket amongst grapes from Brazil.
Habits
This species constructs conspicuous tubular silkenSpider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
nests under rocks and wood on the ground. They remain inside these at night and during bad weather. Molting
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
, 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 2 mm to about 1 cm has been observed. Although found to feed on a wide variety of insects (e.g., flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
, bugs
Homoptera
Homoptera is a deprecated suborder of order Hemiptera; recent morphological studies and DNA analysis strongly suggests that the order is paraphyletic. It was therefore split into the suborders Sternorrhyncha, Auchenorrhyncha, and Coleorrhyncha....
and moth
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
caterpillars and adults), they also prey heavily on spiders. Cannibalism does occur from time to time, in the form of females feeding on males.
Bite
This spider only bites when threatened. The bite results in swelling and pain at the bite site, lasting for several days.External links
- Pictures and description (with pictures of mating dance)
- Picture of a female in her nest
