Sassacus papenhoei Peckham and Peckham, 1895
A Jumping Spider
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Basis for Listing
Although Sassacus papenhoei (a species of jumping spider) is common in the southern United States, it has only spotty distribution north of 35°N latitude. Minnesota has the most northern populations east of the Great Plains. Despite repeated searching in the southeastern corner of the state, S. papenhoei has only been found in Kellogg Weaver Dunes Scientific and Natural Area (SNA) in Wabasha County (and in 2015, the adjacent Nature Conservancy Weaver Dunes SNA) and Whitewater Wildlife Management Area (WMA) in Winona County. The species' preferred prairie and savanna habitat is vulnerable to human disturbance particularly recreational use and irrigated farming. Sassacus papenhoei 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.
Jumping spiders are one of the most recognizable types of spider 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. Sassacus papenhoei is usually about 5 mm (0.2 in.) long and has a shiny black body (which can look iridescent purplish or greenish) with a white crescent on the top side of the front end of the abdomen (Kaston 1978). The first pair of legs is noticeably larger than other pairs. Sassacus papenhoei is stockier than Paradamoetas fontana another special concern species. In overall appearance, S. papenhoei closely resembles other jumping spiders in the genus Bianor having a sheen on the abdomen that may appear blue, red, purple, or green. Maddison (2015) has revised the taxonomic classification for jumping spiders placing Sassacus in the same group as Paradamoetas, Pelegrina, Phidippus, and Tutelina genera, which include four other state special concern species and one state threatened species.
In Minnesota, S. papenhoei has been documented in southern dry sand prairie and southern dry savanna, especially sites rich in native forbs. At Whitewater WMA, an immature specimen was also found in early summer 1996 along a damp floodplain where grass and moss covered sandy soil (Ehmann and Boyd 1997). In contrast, Cutler (1988) only associated the species with xeric sand prairie; specimens from Weaver Dunes SNA were from sand prairie. In the western United States, S. papenhoei is a common to abundant resident of warm and cold desert shrubs such as creosote bush (Larrea tridentata) and big sagebrush (Artemisia tridentata) (Hatley and MacMahon 1980; Abraham 1983; Ehmann 1994).
Biology / Life History
Sassacus papenhoei is similar in body size to Pelegrina species, and they have been found together in desert shrubs. Their coexistence is not all tranquil as S. papenhoei has been observed attacking Metaphidippus (now Pelegrina) aneolus and immature Phidippus johnsoni in Utah (Ehmann 1994). These interactions are in need of more documentation (see Jackson and Pollard 1997). A brief description and a photo of S.papenhoei has been given by Maddison and Hill (2008) in a catalogue of representative jumping spiders of North America.
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 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 spiders, 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 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
Sassacus papenhoei habitat probably needs to be maintained by burning to control shrub invasion, but until more is known about this species' biology, burning should be used judiciously. Burn units on occupied sites must be designed so that not all occupied habitat is burned in any one year.
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 S. papenhoei is from June through September.
Conservation Efforts in Minnesota
Sassacus papenhoei has been rarely collected despite extensive searches by several surveyors in recent years. Perhaps the best approach to learning more about S. papenhoei in Minnesota is to more intensively sample the Whitewater WMA area. All known records of adults through 2015 are from the Paleozoic Plateau ecological section, which matches the distribution of Phidippus apacheanus another special concern species. Suitable habitat in Fillmore, Goodhue, Houston, and Olmsted counties is a priority for future reconnaissance. Any new records continue to be of high interest.