Marpissa formosa (Banks, 1892)
A jumping spider
Basis for Listing
Marpissa formosa (Beautiful Jumper) is known from sites on the East Coast and Gulf Coast as well as from Great Lakes states. There are only seven known occurrences of Beautiful Jumper in Minnesota (two of these records are photographic) in seven counties. Beautiful Jumper was listed as special concern in 2013.
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. Their body shapes and colors often imitate prey such as ants and beetles. Beautiful Jumper is one of four species in the genus Marpissa found in Minnesota. Compared with other jumping spiders, which are commonly stocky in appearance, Beautiful Jumper has an elongate body and long front legs; males have a shiny black head and body, both marked with white spots; the female is brown with a central white stripe on the abdomen that is usually bordered by wide reddish-brown bands. Viewed from the side, the shape of the head (carapace) is flatter than that of other jumping spiders. Males have an overall length of 6-7 mm (0.24-0.28 in.) and females 7-9 mm (0.28-0.35 in.).
In Minnesota, this species has been found as far north as Cass County and as far south as Blue Earth County. Records are from upland prairie, lowland prairie, wet meadow/carr, and marsh communities. In Douglas County, a male was taken from big bluestem (Andropogon gerardi) at Lake Carlos State Park and in Sherburne County, a female specimen was collected at Uncas Dunes Scientific and Natural Area from mixed prairie/meadow including goldenrod (Solidago spp.), cattail (Typha spp.), grasses (Gramineae), and horsemint (Monarda spp.). Barnes (1958) associates this species with shrubs and herbaceous vegetation.
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.
Conservation / Management
With only seven records confirmed over the past 40 years, there is not yet enough information to guide specific management plans.
Conservation Efforts in Minnesota
Surveys are ongoing to determine the distribution of this species in Minnesota.
References and Additional Information
Barnes, R. D. 1958. North American jumping spiders of the subfamily Marpissinae (Araneae, Salticidae). American Museum Novitates 1867:1-50.
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.
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.
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.