Paradamoetas fontanus (Levi, 1951)
A Jumping Spider
Icius fontanus, Paradamoetas fontana
Basis for Listing
Paradamoetas fontanus (a species of jumping spider) has a restricted range in the Great Lakes area of the United States and Canada. The occurrences in Minnesota are at the western periphery of its range. It has been documented from fewer than ten sites in the state, with the most recent record coming from Seven Sisters Prairie (The Nature Conservancy) in 2015. This species’ preferred habitat is vulnerable to human disturbance, particularly drainage. Paradamoetas fontanus 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 middle eyes, and the ability to jump. Their body shapes and colors often imitate prey such as ants and beetles.
Paradamoetas fontanus is glossy black with purplish iridescence, and it is ant-like in appearance. Cutler (1982) gives taxonomic details for this species.
In Minnesota, Paradamoetas fontanus occurs in bogs, marsh edges, mesic prairie, and upland prairie. In 1996, the species was located near cattail marsh edges and near quartzite boulders and seeps (Ehmann and Boyd 1997); in 2015 it was found in a drier site within a gravel prairie. Most localities lie within the Minnesota and Northeast Iowa Morainal ecological section.
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
Paradamoetas fontanus is endemic to the Great Lakes region (Cutler 1981; Wolff 1984). It is best known from Minnesota, suggesting that the Minnesota populations could play a significant role in conserving this species nationally (see also Richman and Cutler 1977). 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.
Best Time to Search
The best time to search for this species is from June through September.
Conservation Efforts in Minnesota
Several known Minnesota localities of P. fontanus are protected including the Cedar Creek Ecosystem Science Reserve and Helen Allison Savanna Scientific and Natural Area (SNA) in Anoka County, Roscoe Prairie SNA and St. Wendel Tamarack Bog SNA in Stearns County, and Seven Sisters Prairie (TNC) in Otter Tail County. Because similar habitats have been sampled elsewhere in the state without success, P. fontanus appears to be very uncommon in Minnesota. It is possible that future sampling with waders or from boats may produce additional records, and any new records will be of interest.