Phidippus pius Scheffer, 1905
A Jumping Spider
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Basis for Listing
The distribution of Phidippus pius (a species of jumping spider) extends across eastern North America, though its occurrence throughout is spotty. The species is believed to be rare due to the destruction of its native prairie habitat (Minnesota's Remaining Native Prairie). In Minnesota, the species is limited to unplowed prairie sites in the south-central and southwestern portions of the state, a habitat that is extremely vulnerable to agricultural development. Phidippus pius has been documented in Minnesota from only six counties, from one site in each. Four of the observations occurred before 1977 and one each occurred in 2013 and 2015, with no repeat observations at any site. It was listed as a special concern species in Minnesota in 1996.
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. The genus Phidippus includes the largest known jumping spider species, which can be up to 22 mm (0.87 in.) long.
Adult male P. pius have a pair of narrow black bands running down the central part of the orange-scaled abdomen, with several pale dots evenly spaced along each band. Similarly, the ground color of the cephalothorax is orange, usually with one or more unscaled dark bands across the anterior portion. Females have similar patterns but appear more orangish gray.The legs and unscaled cephalothorax sides are not black, but orangish to gray-brown. A related species, Phidippus apacheanus can initially be confused with P. pius, but males of P. apacheanus have a cephalothorax thats dorsal side is entirely bright scarlet, while the parts below are glossy black rather than orange-brown.
In Minnesota, P. pius appears restricted to unplowed prairie sites in the south-central and southwestern portions of the state in the North Central Glaciated Plains and Minnesota and Northeast Iowa Morainal ecological sections.
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 use silk to 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 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; 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 feed on other spiders. They will even 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 find prey. Having spotted their 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 may 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 that are specific to that species in front of the female. 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 the males’ courtship dances. After mating, females lay their eggs in their silken retreat and often guard their eggs and newly hatched young.
Conservation / Management
Phidippus pius is known primarily from the southern United States (Richman and Cutler 1977). The few Minnesota specimens collected represent the northwestern-most records for this species. As such, Minnesota populations may yield clues about ecological tolerances and perhaps serve as indicators of prairie habitat quality. Although remnants of natural areas may often be too small or isolated to maintain populations of some rare vertebrates, they may be suitable for maintaining invertebrates. Benign to humans, diverse, colorful, and behaviorally complex jumping spiders may be good ambassadors for their kin and invertebrates in general.
Conservation Efforts in Minnesota
Surveys at or near all four previous known localities of P. pius in early summer 1996 yielded no individuals (Ehmann and Boyd 1997). More recently, however, a single female adult was collected in Kandiyohi County near the Chippewa County boundary (2013), and a single male adult was collected from Joseph A. Tauer Prairie Scientific and Natural Area in Brown County (2015). Both of these are new locations. Given the limited remnants of unplowed prairie, these areas are high priorities for habitat protection and additional survey efforts. Any new records will be of high interest.
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.
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.
Maddison, W. P. 2015. A phylogenetic classification of jumping spiders (Araneae: Salticidae) Journal of Arachnology 43:231-292.
Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the eastern broadleaf forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 394 pp.
Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the prairie parkland and tallgrass aspen parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 362 pp.
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.
Weber, L. 2002. Spiders of the North Woods (North Woods naturalist guides). Kollath-Stensaas Publishing, Duluth, Minnesota. 216 pp.
Wikipedia contributors. 2010. Jumping spider. Wikipedia, The Free Encyclopedia. <http://en.wikipedia.org/wiki/Jumping_spider>. Accessed 15 April 2010.