A source for information on spiders
Ground spider is the name that many people use for a
large group of spiders. The scientific name for the family is Gnaphosidae. There are many species in this family. There
are a few that are fairly common One is the Parson spider, Herpyllus
Ecclesiasticus. This is a blackish spider with white abdominal markings. It is
about 1/3” long. Another is the mouse spider, Herpyllus blackwalli. This spider gets its name from the color of the hair on its body – it is “mousey” gray. The
mouse spider is about 1/2” long.
Ground spiders are one of the most populous species of spiders in the world.
Commonly found dwelling beneath rocks, logs and other objects on the ground, ground spiders rarely leave their
homes except to hunt. These spiders are red or gray-brown in color and may be solid or striped. Ground spiders do
not cause any medical conditions in humans. Due to their reclusive nature, humans rarely see them.
While these spiders do spin silk, they do not trap prey within their webs. Rather,
ground spiders hunt and chase prey along the ground. Hunting typically occurs outside, but ground spiders may also
be seen in homes when temperatures drop significantly.
Ground spiders produce silk through the use of their spinnerets, which are shaped
like barrels. These glands are often instrumental in identifying ground spiders. Also known as endites, the
mouthparts of ground spiders are found in pairs and feature indentations not present on other spider
Ground spiders are nocturnal hunters. They do not make webs to capture prey. They
forage aggressively for insects. During the day, they hide under stones or logs. When they come inside of homes,
they spend the day in dark, quiet places. People who are bitten by spiders often say that it happened when they
picked up something that had been stored for a long time. Shoes in closets are good hiding places for
Preventing ground spiders and other hunting spiders starts with eliminating their
food. Since these spiders eat insects that crawl, inspect the outside for insect entryways. Ground-level entrances
should be closed. Check exterior doors to be sure they close properly. Replace any missing weather-stripping. Check
basement windows and crawlspace vents for proper screens. Squares of plastic screen can prevent insects from using
weep holes as entrances to the home.
Move firewood piles away from the house. Move mulch 6 to 12” away from the
foundation. This will create a “dry zone” that insects (and spiders) will hesitate to cross.
A barrier application of insecticide on the outside foundation can help prevent
insects from coming into the house. Because of moisture and temperature, the barrier will need to be re-applied
periodically. The local pest control professional can do this. They will use an assortment of products for varying
surfaces and weather conditions.
These spiders are small, with a body that is usually less than 1/2-inch in
Color varies, but most species are brown. Some have bright orange or red
Ground spiders are a widely varied group. A few species are commonly
associated with building invasions, especially the Parsons spider which is recognized by the cross-like whitish
marking on its abdomen. Ground spiders are hunting spiders; they do not build webs, but rather chase down their
prey. Most species are night hunters but some are active during the day.
These spiders live outside beneath stones and logs and within leaf litter,
mulch and heavy ground covering such as ivy. Indoors, they may be found scurrying along baseboards and hiding
beneath furniture and appliances.
Ground spiders require few treatments indoors to control, although an exterior
foundation treatment may be necessary in those rare cases where these spiders regularly invade homes. Placement
of sticky insect traps inside your home behind furniture and near doorways may capture many spiders as they
enter. The following tips may be helpful in reducing the number of spiders around the home:
- Remove or limit heavy, ground-covering vegetation near the
- Seal cracks and holes in the building’s exterior.
- Install tight fitting screens on all attic and foundation
- Seal holes around pipes indoors, especially those plumbing lines leading
from basements and crawl spaces, to prevent spiders from entering your home.