Farm Horizons, October 2013
Common spiders in Minnesota
By Christine Schlueter
Spiders are in the gardens everywhere, they are considered beneficial because of the large number of insects they prey on.
All spiders have venom and are venomous. Most spiders are harmless to people. Many are active only at night.
Here are some common Minnesota spiders.
Jumping spiders are common spiders outdoors and indoors.
They are active during the day and are often found around windows, ceilings, walls, and other areas exposed to sunlight. Jumping spiders are generally small to medium-sized (about 1/5 - 1/2 inch long) and compact-looking.
They are usually dark-colored with white markings, although some can be brightly colored, including some with iridescent mouthparts. These spiders move quickly in a jerky, irregular gait.
They get their name from their ability to leap on their prey, often jumping many times their own body length.
Like most spiders, jumping spiders have eight eyes, of which the two middle eyes are particularly large. Jumping spiders have the best vision of spiders, seeing objects up to 8 inches away.
Wolf spiders are common spiders outdoors and are occasionally seen indoors. They are moderate to large-sized spiders (1/4 - 3/4 inch long).
Wolf spiders are found on the ground or under stones in a wide variety of habitats, such as forest floors, grassy meadows, swamps, and bogs. Some even like to live underground.
They commonly hunt during the day or at night when it is warm. Wolf spiders are dark-colored, usually brownish or grayish, with white markings.
Fishing spiders, also known as dock spiders, are typically seen around ponds, swamps, slow-moving streams, and nearby vegetation.
They may occasionally be found indoors. Fishing spiders are the largest spiders in the upper midwest (1 inch long). With legs spread out, some fishing spiders cover as much as 4 inches.
They are generally dark-colored, usually brownish or grayish, with white markings. Fishing spiders can “skate” across water and can dive underneath to capture prey. In addition to insects, fishing spiders can also catch tadpoles, small fish, and other small vertebrate animals.
Sac spiders (also known as two-clawed hunting spiders) are common spiders on foliage or on the ground, and can be commonly found indoors. They are small to medium-sized spiders (1/5 - 2/5 inch long) and are usually yellowish or light-colored.
Although sac spiders do not construct webs, they do build retreats from silk. Outdoors, they usually roll up leaves into a tube, or may construct a retreat under stones.
Inside buildings, sac spiders are found in retreats in a variety of places, including high up on walls near ceilings.
Orb weaver spiders are common spiders outdoors in gardens, fields, and landscapes. They are rarely found indoors.
The orb weaver spiders make the familiar “typical” spider web of concentric circles and radiating lines. They range in size from small to large (1/8- to 1-inch long) and are found in a variety of colors, some being brightly colored.
Orb spiders have large, swollen-looking abdomens, including some that are oddly shaped. Despite their large size and bright coloration, orb weaver spiders are not dangerous.
Spiders are predators feeding mainly on living insects, mites, and other small arthropods. Spiders are considered beneficial because of the large number of insects they prey on, including a number of pest species.
All spiders have venom that is injected through the hollow fangs (chelicerae) into the living prey to immobilize the prey and begin the digestion process. Spiders feed by liquefying the prey with digestive fluids that are injected or regurgitated into the prey and then sucking in the digested food.