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By Katie Knight
Geographic Range
Bold jumping spiders, Phidippus audax, are very common in North America, but appear more frequently along the East Coast. There have also been sightings of bold jumping spiders in Eastern Canada. No sightings have occurred outside North America. (Huntley, 1997; Jackman, 1997; Vest, 1999)
Habitat
Bold jumping spiders are most frequently found in gardens. They live around human dwellings on objects such as tree trunks, vegetation, under stones, and on boards. They are not reluctant to enter houses. (Jackman, 1997; Vest, 1999)
These animals are found in the following types of habitat:
temperate 
; terrestrial .
Terrestrial Biomes:
desert or dune ; savanna or grassland ; chaparral .
Other:
urban ; suburban ; agricultural .
Physical Description
(0.24 to 0.59 in)
The most distinctive features on P. audax are the eight eyes. The forward-facing anterior median (AM) eyes are the largest of all the eyes. When a person looks at the spider, the AM eyes are the ones that look back at that person. To the side of the AM eyes are the smaller anterior lateral (AL) eyes. Behind the AL eyes, and almost on top of the head, are the posterior median (PM) eyes and posterior lateral (PL) eyes. Jumping spiders have very keen eyesight. Eyesight is essential for hunting and courting.
Females measure from 8 to 15 mm in length, and males are between 6 and 13 mm.
Bold jumpers are extremely hairy. The cephalothorax and abdomen are black with little, white hairs. The cephalothorax is high, heavy, and convex. The abdomen is distinctly marked. In the middle of the abdomen, there is a large, triangular white spot. There are several other spots, ranging in color from white to even yellow or orange. These spots are posterior to the central triangular spot. In some individuals there are two oblique lateral stripes. Many have chelicerae (mouthparts) that are iridescent green.
The powerful hind legs are responsible for propelling the spider into a leap. To obtain food, a jumping spider pounces on its prey. This species could not perform this difficult task without the great ability of the hind legs. (Comstock, 1980; Huntley, 1997; Jackman, 1997; Kaston, 1978)
Some key physical features:
ectothermic ; bilateral symmetry .
Sexual dimorphism: female larger.
Reproduction
In males, a pair of coiled testes lie in the anterior part of the abdomen. There is no copulatory organ, so the seminal fluid is transferred to a female by a highly specialized appendage of the palpus during copulation. Females possess ovaries, oviducts, a uterus, a vagina, and one or more spermathecae (pouches for the reception of the seminal fluid). All the reproductive organs are located in the abdomen in both males and females.
The process of copulation begins with a male courting a female. The male lifts certain legs and shows off his colored spots. This behavior is restricted to P. audax. If the female approaches too rapidly, the male will jump away. After copulation takes place, the female produces an egg sac under a silk blanket. She attends to the egg sac until spiderlings disperse. The spiderlings are able to grow and take care of themselves without the help of their mother. (Comstock, 1980; Knopf, 1980; Preston-Mafham and Preston-Mafham, 1996)
Females protect their egg sac until the young spiderlings disperse. There is no apparent parental care in this species. (Comstock, 1980; Knopf, 1980; Preston-Mafham and Preston-Mafham, 1996)
Parental investment:
precocial ; pre-fertilization (protecting: female); pre-hatching/birth (protecting: female); pre-independence (protecting: female).
Behavior
Bold jumpers hunt alone during the day. Phidippus audax actively watches its prey with its sharp vision. It then sneaks up on its victim and pounces on it. When bold jumping spiders jump, they release a line of webbing for security. This ensures that if a leap fails, there is a safety line that will catch the spider before it falls. Hunting and courting are the only activities that individuals continuously perform. (Huntley, 1997; Jackman, 1997; Vest, 1999)
Communication and Perception
Visual communication plays a role in reproductive behavior. Males use visual signals, such as leg lifting, to communicate with potential mates. Tactile communication is also of some importance, since physical contact is required for males to transfer gametes to females. (Comstock, 1980; Knopf, 1980; Preston-Mafham and Preston-Mafham, 1996)
Food Habits
Jumping spiders are carnivorous predators. They eat insects and other spiders. They have been known to feed on boll weevil adults, tarnished plant bugs, adults and larvae of bollworms, pink bollworms, tobacco budworms, and cotton leafworms. In Idaho, P. audax attacks, kills, and eats hobo spiders. Bold jumping spiders actively hunt during the daytime, but not at night. These spiders use their keen eyesight to scope out prey,then they spring upon the prey and bite it, releasing venom. The victim is incapacitated. (Huntley, 1997; Jackman, 1997; Vest, 1999)
Primary Diet:
carnivore (insectivore ).
Animal Foods:
insects; terrestrial non-insect arthropods.
Ecosystem Roles
Phidippus audax is an important predator of insects, and as such impacts insect populations.
Economic Importance for Humans: Negative
Bold jumping spiders will bite humans if cornered, handled, or threatened. Gardners are at highest risk of being bitten. However, this is very rare, and bites are usually asymptomatic to slightly painful. A local reaction might occur, such as an erythematous papule or a small urticarial wheal. Aside from occasional bites, this species does little more than frighten an occasional arachniphobe. (Huntley, 1997)
Ways that these animals might be a problem for humans:
injures humans (bites or stings).
Economic Importance for Humans: Positive
Phidippus audax has not been reported as having direct economic benefit to humans. However, as predators of many insects that are damaging to cotton crops, these spiders may help to curb populations of these detrimental insects.
Ways that people benefit from these animals:
controls pest population.
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
State of Michigan List: [link]:
No special status.
Currently, P. audax and its habitat are not threatened. This spider is quite common and abundant.
Other Comments
The eyes of the bold jumper are incredible. The anterior median eyes form sharp images while the anterior lateral eyes can judge distance. Phidippus audax is a superior hunter because of this phenomenal advantage. (Wise, 1993)
Contributors
Katie Knight (author), Southwestern University.
Stephanie Fabritius (editor), Southwestern University.
Nancy Shefferly (editor), Animal Diversity Web Staff.
