Marpissa grata    (Gertsch, 1936)

A Jumping Spider 


MN Status:
delisted
Federal Status:
none
CITES:
none
USFS:
none

Group:
spider
Class:
Arachnida
Order:
Araneae
Family:
Salticidae
Habitats:

(Mouse over a habitat for definition)


Marpissa grata

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Map Interpretation

Map Interpretation

  Synonyms

Hyctia grata, Marpissa wallacei

  Basis for Former Listing

Marpissa grata is a Great Lakes endemic known only from Michigan and Minnesota. It was originally collected by Gertsch (1936) in Minneapolis, Minnesota, and is now known from 10 additional counties. This suggests that the Minnesota populations may be significant to the conservation of this species nationally. Marpissa grata was listed as a special concern species in Minnesota in 1996. Special concern jumping spiders 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.

  Basis for Delisting

Since its listing as a special concern species, M. grata has been found at several new locations, suggesting that it is more widespread than originally thought. Thus, its special concern status was determined to no longer be necessary. Marpissa grata was delisted in 2013.

  Description

Jumping spiders are one of the most recognizable spiders, as they generally have a stout body, rather short legs, a very large set of eyes, and the ability to jump. They also walk with an irregular gait. Their body shapes and colors often imitate prey such as ants and beetles. Marpissa grata has a very elongate abdomen, and is dark brown in color with central yellow patches. The similar M. pikei has been associated with more xeric habitats and has faint spots on a light background in irregular lines along the length of the abdomen.

  Habitat

Marpissa grata prefers habitat that contains sedges or emergent vegetation. Most, but not all, records are associated with wetlands, ponds, or rivers. All specimens collected by Ehmann and Boyd in 1996 were near cattail (Typha spp.) marshes, in grass, and on cattails and willows (Salix spp.). However, several specimens collected in 2004 in Otter Tail County were from a drier site dominated by big bluestem (Andropogon gerardii). Cutler (1971) linked this species to bluegrass (Poa pratensis) meadows and this association has held true at Lake Elmo Park Reserve in Washington County (Ehmann and Boyd 1997).

  Biology / Life History

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 will 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 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, and they are able to identify prey, predators, and mates from up to a foot 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, although 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 find prey. Having spotted a potential victim, 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 visual capabilities of jumping spiders that are critical to their performance as hunters also support complex courtship behaviors. Males often differ in appearance from females and my 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 female that are specific to each species. The male's movements range from a slight lifting of a leg to complex movements, such as bobbing their bodies, twitching their abdomen, performing zigzag movements, waving their front legs, or flashing their mouthparts into the eyes of the females. Some male jumping spiders may also have auditory signals which 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 will often guard their eggs and newly hatched young.

  Conservation / Management

The best time of year to survey for M. grata is from June through September. Future surveys may want to employ alternative sampling techniques to sweep netting such as hand searches and leaf litter collection. Although remnants of natural areas may often be too small or isolated for 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 may 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.

  Conservation Efforts in Minnesota

In 1996, Ehmann and Boyd (1997) confirmed the presence of M. grata in Stearns County, previously reported by Cutler (1988), and within Washington County at a new locality. Significantly, M. grata was also discovered in Murray County in 1996 and in Jackson County in 2007, which extended the range limit of this species more than 200 km (124 mi.) southwest. A single adult specimen was collected in Sherburne County for the first time in 2001 (Ehmann 2002) and in 2004 several adult and immature specimens were collected at two sites in Otter Tail County. The absence of M. grata in apparently suitable habitat elsewhere in the state combined with extremely low collection numbers from sites where it is found is consistent with the interpretation that this species is rare in Minnesota. Any new records will be of high interest.

  References

Barnes, R. D. 1958. North American jumping spiders of the subfamily Marpissinae (Araneae, Salticidae). American Museum Novitates 1867:1-50.

Cutler, B. 1971. Spiders from heading bluegrass (Poa pratensis L.) in Roseau County, Minnesota. Michigan Entomologist 4:123-127.

Cutler, B. 1988. Final report to the Invertebrate Group Committee. Pages 423-431 in B. Coffin and L. Pfannmuller, editors. Minnesota's endangered flora and fauna. University of Minnesota Press, St. Paul, Minnesota.

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.

Gertsch, W. J. 1936. Further diagnoses of new American spiders. American Museum Novitates 852:1-27.

Kaston, B. J. 1955. Checklist of Illinois spiders. Transaction of the Illinois Academy of Science 47:165-172.

Levi, H. W., and H. M. Field. 1954. The spiders of Wisconsin. American Midland Naturalist 51:440-467.

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.

Minnesota Department of Natural Resources. 2012. Statement of need and reasonableness. Minnesota Department of Natural Resources. Division of Ecological and Water Resources. St. Paul, Minnesota. 337 pp.

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.