Phidippus apacheanus Chamberlin and Gertsch, 1929
A Jumping Spider
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Basis for Listing
Phidippus apacheanus (a species of jumping spider) is a common species in the southern United States, from Florida to California. However, it appears to be of local occurrence north of 30° to 35°N latitude. It is rare in the Upper Midwest, known only from a few locations in southwestern Wisconsin and southeastern Minnesota. In Minnesota, the species is limited to undisturbed native prairie, a rapidly diminishing habitat type (Minnesota's Remaining Native Prairie). Phidippus apacheanus has been collected at just three sites in the state, the most recent being from 1982. It was listed as a special concern species in Minnesota in 1996. Special concern spider species are those known from three or more sites in Minnesota but with significant range restrictions or particular habitat associations that make their populations appear vulnerable from a conservation standpoint.
Phidippus apacheanus is a large, stocky, showy jumping spider. The males are glossy black, with bright red-orange backs and rings on their legs; and in comparison to adult male Phidippus pius, the red-orange areas cover much more of the cephalothorax (head). Adult females have a pattern on the head similar to the males. According to Edwards and Hill (2008), the bright red scales are thought to mimic patterns of mutillid wasps (also called velvet ants). The females are similar, but also have a few, black markings on their backs. This species is often over 1 cm (0.4 in.) long, and the front of the jaws are iridescent. Maddison (2015) has revised the taxonomic classification for jumping spiders, placing Phidippus in the same group as Paradamoetas, Pelegrina, Sassacus, and Tutelina genera, which include three other state special concern species, and one state threatened species.
In Minnesota, P. apacheanus is known only from the southeastern corner of the state (The Blufflands) in dry prairie, a diminishing habitat type (Minnesota's Remaining Native Prairie). Elsewhere, the species has been found in a variety of open habitats including sagebrush flats in Utah.
Biology / Life History
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 pair of large, principal eyes 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, which, 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
Although P. apacheanus has a large range, the scant Minnesota records define its northernmost extent, suggesting an opportunity to learn more about this species' ecological tolerances. Although remnants of natural areas may often be too small, or isolated to maintain the viability of some rare vertebrates, they may be suitable for maintaining invertebrates. Each new locality for a species adds to the suite of management options for their conservation, and can even guide new land designations or acquisitions. Benign to humans, diverse, colorful, and behaviorally complex, jumping spiders may be good ambassadors for their kin, and invertebrates in general.
Best Time to Search
The best time of year to survey for P. apacheanus is from August through September.
Conservation Efforts in Minnesota
Surveys of all known localities of P. apacheanus conducted in early summer 1996 were unsuccessful at relocating this species (Ehmann and Boyd 1997), as were surveys in Wabasha County in 2015. All known records are from extreme southeastern Minnesota on the Paleozoic Plateau and so, besides known localities, the unsampled counties of Goodhue, Houston, and Olmsted merit attention. The distribution of Sassacus papenhoei, another special concern jumping spider in Minnesota, is similar to that of P. apacheanus. Late-season sampling, including hand searches, may yield new records. Any new records, including date of collection, behaviors observed, and habitat details will be of high interest.
Dr. William J. Ehmann, Ecologist, 2008 and 2017
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. Unpaged.
Foelix, R. F. 1996. Biology of spiders. Oxford University Press, New York. 330 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) - a preliminary draft.
Jackson, R. R., and S. D. Pollard. 1997. Jumping spider mating strategies: sex among cannibals in and out of webs. Pages 340-351 in J. C. Choe and B. J. Crespi, editors. Mating systems in insects and arachnids. Cambridge University Press, Cambridge, Massachusetts.
Maddison, W. 2006. Jumping spiders of American north of Mexico.
Richman, D. B., and B. Cutler. 1977. A list of jumping spiders (Araneae: Salticidae) of the United States and Canada. Peckhamia 1:82-109.
Weber, L. 2002. Spiders of the North Woods. Kollath-Stensaas Publishing, Duluth, Minnesota. 205 pp.
Wikipedia contributors. 2010. Jumping spider. Wikipedia, The Free Encyclopedia. <http://en.wikipedia.org/wiki/Jumping_spider>. Accessed 15 April 2010.