Common Name: Jumping Spiders or Salticids
Scientific Name: Various
The common name comes from their jumping ability and habit which they use to capture prey. They are an occasional nuisance pest indoors, and some black colored species may cause concern when people mistake them for black widow spiders, Latrodectus spp. About 300 species are found in the United States and Canada.
Adult body length about 1/8-3/4″ (4-18 mm); robust, compact with relatively short legs. With 8 eyes in 3 rows, front row of 4 eyes with middle pair very large, 3rd row of 2 moderately large eyes at about midlength of cephalothorax, and middle row of 2 small eyes about midway between 1st and 3rd rows. Color usually black, sometimes brown, tan, or gray, and usually with pale markings of white, gray, yellow, red, blue and/or green; typically densely covered with hairs or scales, these often brightly colored or iridescent. Front legs usually thicker and somewhat longer than other legs; tarsi with 2 serrate (tooted) claws each. No snare webs, quick to jump, with jumping power generally supplied by the 4th pair of legs. Note that there are 3 genera with species which mimic ants, having cephalothorax slightly pinched in at middle to resemble head and thorax and front legs held up and bent like elbowed antennae; these species do no jump.
(1) Crab (Thomisidae) and giant crab (Sparassidae) spiders have body usually flattened with legs positioned/held at right angle to sides giving a crablike appearance and many species with horns or ornaments on cephalothorax and/or abdomen.
1. Phidippus audax (Hentz). Adult female body length about 5/16-5/8″ (8-15 mm), male about 1/4-1/2″ (6-13 mm); color blackish with basal white band and paired white (sometimes yellow or orange) spots on abdomen, largest spot (=fused 2nd pair) triangular, in center, and pointing towards front, sometimes cephalothorax with white lateral bands extending back from rear eyes and abdomen with lateral white bands and tan pattern; male (with swollen terminal segments of palps) with large blunt cusp/knob of front of each chelicera near fang; found throughout the United States and southern Canada.
2. Zebra spider, Salticus scenicus (Clerck). Adult female body length about 3/16-1/4″ (4.3-6.4 mm), male 1/8-1/4″ (4-5.5 mm); color gray (often with brown to reddish scales intermixed) with white markings on cephalothoracic front (with iridescent scales), behind rear pair of eyes, and laterally, and on abdomen as basal band, middle band interrupted at midline, and rear band usually interrupted at midline, legs white or brown with gray rings; male with chelicerae elongate, extending almost horizontally forward, and fangs long and sinuate; found throughout northern Untied States and southern Canada.
Jumping spiders do not construct snare webs but do build web retreats which are loosely woven saclike, composed of several envelopes, and usually have 2 openings. These retreats are used for molting, hibernation, night-time seclusion, and egg laying; often a different retreat is built for each function/activity. The egg sacs are typically lens-shaped and suspended like a hammock from the retreat’s walls. There is usually only 1 egg sac, but occasionally there may be several present at one time.
In the New England states, the zebra spiders mate in May and eggs are laid in June and July. Each egg sac contains 15-25 white eggs. Presumably, the older spider lings overwinter in the retreat and become adults in spring. Adult males are found April to July and females from mid-May to late October.
Unlike most spiders, jumping spiders are active during the daytime and seem to like sunshine. They are hunters and have the keenest vision of all spiders, being able to detect and react to movement up to 18″ (45 cm) distant; however, their night vision is very poor. They can rapidly move both sideways and backward for short distances. They are excellent jumpers. They either jump on passing prey, or once they locate prey, it is stalked and then pounced upon.
When hunting they may jump 1″ or more (25+ mm) but when threatened, they may jump 20 times their body length. They employ silk as a dragline when they jump; the dragline is anchored before they jump and acts as a safety line. Retreats may be built under furniture, in drapery folds, between books on bookshelves, in cracks such as found in wood floors, around windows and doors because more insects are attracted to these areas. Also, their vision is best in sunlit areas. Outdoors, jumping spiders are commonly seen running over tree bark, under stones and boards, on bushes, fences, decks, and the outside of buildings, etc. They like sunny areas.
Follow the standard control procedures for spiders outlined in the introductory section except pesticide application is rarely warranted. Exclusion and the removal of outdoor harborage is key. Indoors, removal with a vacuum is best followed by disposal of the vacuum bag outside.