brilliant jumping spider

Common and widespread. Very common in Minnesota

June to September

A wide range of habitats, especially old fields and weedy areas in open woodlands

Brilliant jumping spider occurs across North America from coast to coast. It is common east of the Great Plains, less common on the West Coast, and absent form the desert southwest. It is very common in Minnesota. A study in 1997 surveyed jumping spiders in 30 locations around Minnesota. The author collected 572 jumping spiders representing 15 species. Brilliant jumping spider was by far the most common, with 299 specimens (52%) collected.

Brilliant jumping spider is found from July to September in moderately moist fields on grasses and perennial plants. It is a small to medium-sized spider (order Araneae) but a relatively large jumping spider (family Salticidae).

The male is mostly black and 3 ⁄16″ to ¼″ long not including the legs. The front part of the body (cephalothorax) is robust. The plate covering the cephalothorax (carapace) is high, longer than wide, black, shiny, and iridescent. The abdomen is black with a white band around the front; a broad; a reddish-orange longitudinal stripe on each side; and four pairs of small white spots on or bordering a pair of thin, black, longitudinal stripes near the middle. The legs are short, hairy, and black, with pale bands near the end of each segment.

The female is larger, 5 ⁄16″ to ½″ long and has bronze-red to gold scales on the carapace. The abdomen is variable in color. The light form female is varying shades of gray, tan, brown, and orange. The dark form female is colored similar to the male. The colors may be an adaptation to the local environment. The light form may help to camouflage the spider from birds, while the dark form with bright reddish-orange may be warning coloration to predators that avoid wasps. The legs on the light form are pale with dark bands near the end of each segment.

There are four pairs of eyes arranged in what appears to be three rows. The first row of four eyes is recurved. The middle and forward-most pair of these is by far the largest of all of the eyes and can be moved. The second row of two eyes is closer to the first row than it is to the third row, which is set far back on the head. The second and third rows form a square. The jaws (chelicerae) are small. The basal parts of the chelicerae are iridescent green or blue. There are two sensory appendages (palps) associated with the mouthparts. Each palp has a conspicuous white stripe on top (dorsally).

Insects and other spiders

The female is a paragon of parental perseverance. In the fall she creates a large white egg sac at the top of a tall grass or herbaceous plant and drops eggs into the sac. She prevents the eggs from drying out by repeatedly adding silk to cover the egg mass. She stays with the egg sac until the young disperse in about a month. During this time she does not feed and usually dies from starvation a few days later.

The eggs are highly parasitized by flies, mantis-flies, and wasps due to the exposed location of the egg sac.

Early stage spiderlings overwinter. Adults reach maturity in mid-summer

They hunt during the day by sneaking up and pouncing on their prey. They release silk while jumping as a drag line to prevent falling. They do not hunt at night.

They will bite if molested but are usually too quick and wary to be caught. They can jump 10 to 50 times their body length.

Location: Woodbury, Minnesota