What do they look like?

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.

These spiders are hairy; 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, with two smaller spots posterior and lateral to the large spotk. The large spot may be orange in juveniles, and there is some variation in spot patterns within the species, though spots are always white, yellow, or orange. In some individuals there are two oblique lateral stripes. The chelicerae are iridescent green. Males are smaller than females, with more starkly contrasting markings, and more iridescence on the chelicerae.

The powerful hind legs are responsible for propelling the spider into a leap.

This species is venomous, but the bite is not dangerous to humans.

Where in the world do they live?

Bold jumping spiders, Phidippus audax, occur across North America from southeastern Canada west to British Columbia, and south to Florida, the Gulf Coast and northern Mexico. The species may have been absent from the arid southwest prior to modern settlement and irrigation, but have been introduced there by human activity. The species also occurs on the island of Cuba, and has been introduced to the Hawaiian Islands as well.

What kind of habitat do they need?

The natural habitats of bold jumping spiders are are grasslands, prairies, and open woodlands. They also occur in agricultural habitat, especially old fields, and are frequently found in backyards and gardens.

How do they reproduce?

The process of copulation begins with a male courting a female. There is a species-specific courting display, which includes movement of the forelegs, palps and chelicerae. The male lifts certain legs and shows off his colored spots. If the female approaches too rapidly, the male will jump away.

Bold jumpers mature in spring, mate in late spring or early summer, then females produce multiple egg sacs over the summer. A female may produce as many as 6 clutches of eggs, each containing 30-170 eggs. Average fecundity is about 200 eggs per female. Later clutches tend to be smaller than earlier ones. Breeding in warmer climates may be more continuous, and adults may survive longer.

Females make a silk shelter for their eggs, and guard them until they hatch and the spiderlings disperse.

How do they behave?

Like most jumping spiders, 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. Jumping spiders have much better vision than other spiders and are alert for prey and predators.

Where temperatures drop to near or below freezing, juveniles of this species will seek out protected refuge spaces and go dormant during the winter.

How do they communicate with each other?

Like all jumping spiders, bold jumpers have good vision (compared to other types of spiders), and use vision more than most spiders. They also have keen senses of touch, and can smell and taste. They locate prey and predators mainly with their vision.

Visual communication plays a strong role in reproductive behavior. Males use visual signals, such as leg lifting, to communicate with females. They use their sense of smell to find the general location of potential mates.

What do they eat?

Jumping spiders are carnivorous predators. They eat a wide variety of insects and other spiders. They have been studied in cotton fields, where they were found to eat several pest species, including boll weevils, tarnished plant bugs, and adults and larvae of bollworms (moths that attack cotton), including pink bollworms and tobacco budworms. In Idaho, P. audax was observed preying on hobo spiders.

Bold jumping spiders actively hunt during the daytime, but not at night. These spiders use their keen eyesight to locate prey,then they spring upon the prey and bite it, releasing venom. They have been observed to have different stalking strategies for different types of prey, approaching flies from a different angle and jumping from a different distance than they do caterpillars. Male and female bold jumpers hunt differently too. Males prefer smaller prey, and spend less time hunting and feeding. Females prefer larger prey, feed more often, and process prey more to get more food from them.

What eats them and how do they avoid being eaten?

Bold jumpers will quickly flee from animals that are too large to eat, jumping down and away or hiding in small crevices. At night they hide in a crevice or small cavity and make a ilk retreat to avoid predators that hunt by touch.

Dragonflies are known to attack them, and birds and lizards do as well.

What roles do they have in the ecosystem?

Phidippus audax is an important predator of insects, and as such impacts insect populations.

Do they cause problems?

Bold jumping spiders may bite humans in self-defense if grabbed or pressed. 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.

How do they interact with us?

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.

Are they endangered?

Currently, P. audax and its habitat are not threatened. This spider is quite common and abundant.

Some more information...

The eyes of the bold jumper are very strong, compared to most arthropods. The anterior median eyes form sharp images while the anterior lateral eyes can judge distance. In vertebrates eyes, the lens is moved to adjust the focus, but in jumping spider eyes the lens is fixed and the retina moves.

Contributors

Katie Knight, Southwestern University

Stephanie Fabritius, Southwestern University

Contributors

Nancy Shefferly, Animal Diversity Web

Contributors

George Hammond, Animal Diversity Web, University of Michigan Museum of Zoology

References

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Knopf, A. 1980. The Audubon Society Field Guide to North American Insects & Spiders. New York: Chanticleer Press, Inc..

Preston-Mafham, K., R. Preston-Mafham. 1996. The Natural History of Spiders. Ramsbury, Marlborough: The Crowood Press.

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Wise, D. 1993. Spiders in Ecological Webs. New York: Cambridge University Press.

Barnes, J. 2004. "Arthropod Museum Notes #33, Bold Jumping Spider" (On-line). Arthropod Museum, University of Arkansas. Accessed March 08, 2012 at http://www.uark.edu/ua/arthmuse/boldjump.html.

Suman, T. 1964. Spiders Of The Hawaiian Islands: Catalog and Bibliography. Pacific Insects, 6: 665-687. Accessed March 06, 2012 at http://hbs.bishopmuseum.org/pi/pdf/6(4)-665.pdf.

Roach, S. 1988. Reproductive periods of Phidippus speces (Araneae, Salticidae) in South Carolina. Journal of Arachnology, 16: 95-101. Accessed March 07, 2012 at http://www.americanarachnology.org/JoA_free/JoA_v16_n1/JoA_v16_p95.pdf.