Rare Species Guide

  Basis for Listing

Habronattus viridipes (a species of jumping spider) is known from sites on the East Coast and Texas as well as from Great Lakes states. The Minnesota specimens establish the known northwestern range limit for H. viridipes in the U.S. (Griswold 1987). Historically (1934 and 1935), there were three known occurrences of adult H. viridipes in Minnesota (Goodhue, Ramsey, and Crow Wing counties). Since that time, about a dozen new occurrences have been confirmed in nine counties. Habronattus viridipes was listed as special concern in 2013.

  Description

Jumping spiders are one of the most recognizable types of spiders as they generally have a stout body, rather short legs, a very large set of eyes, and the ability to jump. Their body shapes and colors often imitate prey such as ants and beetles. "Viridipes" means “green foot”, and in H. viridipes the male’s front pair of legs has a distinct green tint. Habronattus viridipes is also one of 12 similar species described by Griswold (1987) in which males have unusual modifications to parts of their third legs, typically described as "bumps" or "knobs" by amateurs. In this species, a triangular “bump” sticks out from the third leg that can be seen with the aid of magnification. The male H. viridipes has a light narrow band down the center of a dark abdomen, but it is not as wide as for H. c. maddisoni. The female is brown with grey legs and not easily identified in the field.

  Habitat

This species has generally been found in central and southeast Minnesota. Preferred habitats include sand prairie such as at Helen Allison Savanna and Weaver Dunes Scientific and Natural Areas, hill prairie such as at Seven Sisters Prairie (The Nature Conservancy), and oak savanna such as at Cedar Creek Ecosystem Science Reserve.

  Biology / Life History

Very little is known about the specific details of the biology and life history of this species, but it shares a number of general traits with other species in the group.

Jumping spiders do not spin webs for catching prey. Instead, they construct small tent-like silken retreats under rocks or logs or on plants, which they use at night and during hibernation. The females also lay their eggs in them. Jumping spiders are most active during the day, and they prefer sunshine. They tend to stay in their retreats on cloudy or rainy days. Jumping spiders are generally interested in whatever approaches them and will often turn and face human observers and may even advance towards them. They are generally harmless to people.

Jumping spiders have four pairs of eyes with the large principal pair giving them better vision than other spiders. The forward-looking placement of this pair of eyes provides binocular vision enabling them to judge distances accurately, and they are able to identify prey, predators, and mates from up to 30 cm (1 ft.) away (Weber 2002). Physiological and behavioral experiments have demonstrated that they have color vision, possibly extending into the ultraviolet range.

Jumping spiders feed primarily on insects, though some may feed on web-building spiders. They will also feed on other jumping spiders, usually those that are smaller than themselves. Jumping spiders actively stalk their prey instead of snaring it in a web. They may, however, steal insects snared by the webs of other spiders. Jumping spiders hunt primarily during the day, using their keen eyesight to locate prey. Having spotted a potential quarry, a jumping spider will slowly stalk the prey until it is within jumping distance. Then it lifts its front legs and pounces. Like all spiders, jumping spiders move their legs not by muscular contractions but by changing the pressure of the fluid within them. This hydraulic system enables them to jump up to several times their body length without having large muscular legs. Before jumping, the spider always affixes a silk safety line to whatever it is jumping from; in case it falls, it can climb back up this tether.

The same visual capabilities that are critical to jumping spiders’ success as hunters also support complex courtship behaviors. Males often differ in appearance from females and can have colorful, sometimes iridescent, modifications to their bodies, front legs, or mouthparts. The parts of the male's body that are used in courtship are often conspicuously colored. In many jumping spider species, the males perform courtship dances in front of the females that are species specific. The male's movements range from a slight lifting of a leg to complex movements such as bobbing their bodies, twitching their abdomen, performing zig-zag movements, waving their front legs, or flashing their mouthparts into the eyes of the females. Some male jumping spiders also have auditory signals that, when amplified, sound like buzzes or drum rolls. It is presumed that females choose mates based on their courtship dances. After mating, females lay their eggs in their silken retreat and often guard their eggs and newly hatched young.

  Conservation / Management

With only 13 records confirmed over the past 40 years, there is not yet enough information to guide specific management plans.

  Conservation Efforts in Minnesota

Surveys are ongoing to determine the distribution of this species in Minnesota.

  References and Additional Information

Ehmann, W. J. 2002. Conservation biology of special concern jumping spiders (Araneae: Salticidae) of Minnesota. Final Report submitted to the Natural Heritage and Nongame Research Program, Minnesota Department of Natural Resources. 11 pp.

Ehmann, W. J., and B. E. Boyd. 1997. Surveys for proposed special concern jumping spiders of Minnesota. Final report submitted to the Minnesota Department of Natural Resources. 18pp.

Foelix, R. F. 1996. Biology of spiders. Second edition. Oxford University Press, New York, New York. 336 pp.

Forster, L. M., and M. R. Forster. 1999. How do jumping spiders catch up on their prey?: a model for pursuit behaviour. (Araneae; Salticidae). Preliminary Draft, 06 Aug 1999.

Griswold, C. E. 1987. A revision of the jumping spider genus Habronattus F. O. P.-Cambridge (Araneae: Salticidae), with phenetic and cladistic analyses. University of California Publications on Entomology 107. University of California, Berkely. 344 pp.

Maddison, W. 1994. Jumping spiders of America north of Mexico [web application]. Tree of Life web project, University of British Columbia, Vancouver, Canada. <http://tolweb.org/accessory/Jump>. Accessed 16 Aug 2006.

Richman, D. B., and B. Cutler. 1978. A list of the jumping spiders (Araneae: Salticidae) of the United States and Canada. Peckhamia 1(5):82-110.