Indoor Spiders Found in Central Indiana

In central Indiana, you may be sharing your home with a variety of spider species.

Because of central Indiana's distinct seasons, including very cold winters and very hot summers, some spiders may venture inside to seek shelter from the elements. All spiders are capable of biting, but the brown recluse is the only medically significant, commonly found indoor species for the region. Sac spiders can produce a necrotic wound like brown recluses, although they are rarely as significant. Most spiders are regional, not exclusive to central Indiana.

American House Spider and Cellar Spiders

The American house spider is responsible for most of the webs that are known commonly as "cobwebs." They prefer indoor environments, although they are rarely seen by their human co-inhabitants. The male of this species is one-eighth of an inch one-fourth of an inch long, while the female is one-fourth of an inch long. They have bulbous bodies that are streaked and splotched with black and brown. These spiders make irregular webs anywhere they can attach a web to, particularly corners of walls and windows. They feed on insects, serving as natural pest-control agents.

Cellar spiders prefer dark and damp places, hence their name. Many people mistake them for daddy-long-legs, although they are very different. You can often find them hanging upside down in their webs. They have elongated abdomens and long legs.

Wolf Spiders

Although they prefer outdoor habitats, members of the wolf spider family are common inside. Wolf spiders scare many people because they are often large, sometimes hairy and can move very fast to escape a human or chase prey. These spiders do not build webs because they are active hunters. During the warmer months, such as central Indiana's summer and early fall, these spiders come indoors accidentally while searching for prey. During Indiana's cold winters, starting in late fall, the spiders move indoors seeking refuge and a winter retreat.

Wolf spiders vary in color, but most are brown or black and may have stripes. Their eyes reflect light like many mammals. The female wolf spider will carry her egg sac with her, and many times the spiderlings will hitch a ride on their mother's back until they are old enough to fend for themselves.

Sac Spiders

Sac spiders are more than likely responsible for most of the spider bites reported inside the home. Like wolf spiders, they do not spin webs to catch their prey; they are active hunters. They get their name by the silken retreat they spin, which resembles a sac. These spiders often build these sacs high up in the corners of walls or other retreats. These nocturnal spiders scurry quickly away from humans, and if disturbed may drop from the wall or ceiling. Bites often occur when an unknowing human slips into bed with a hiding sac spider.

Other Common Indoor Spiders

Central Indiana is home to many spiders, some of which accidentally enter homes. Many species are more commonly found in homes than others. Jumping spiders, for example, sometimes relish the chance to sit on a window sill and wait for prey. These spiders are generally more docile than most, sometimes sitting calmly in the palm of your hand if you pick them up.

Brown recluse spiders, also known as violin spiders or fiddlebacks, also call central Indiana home. These spiders are one of two venomous species found in central Indiana, the other being the black widow. Brown recluse spiders prefer dark hiding places, and you might find them in basements, storage units, behind furniture and along baseboards. They are slightly large, light brown spiders with a dark brown violin-shaped marking behind their eyes.

References

• "National Audubon Society Field Guide to North American Insects and Spiders"; Milne and Milne; 1980
• Ohio State University Extension; Spiders In and Around the House; Susan C. Jones, Ph.D., Extension Specialist
• University of Kentucky; Common Spiders Found Around Homes and Buildings; Lee Townsend and Ken Yeargan; January 1994

Resources

• Insect Identification: Homepage