Spiders – Common Species and Management In and Around Homes
Xing Ping Hu
Urban Entomologist, Department of Entomology/ACES
There are numerous spiders associated with human living habitats. Spiders are arachnids, not
insects. Spiders have eight legs and two body parts—a head region (cephalothorax) and an
abdomen. They lack wings and antennae.
Two images come to mind when mentioning spiders: webs and bites. Webs are often associated
with un-maintained areas, and abandoned/neglected homes. Bites occur only when humans
unintentionally press up or touch against spiders that are able to deliver a medically significant
dose of venom to humans in one bite.
Spiders are beneficial, feeding mostly on small insects and other arthropods. Most species
found in homes and buildings are “accidental invaders” that have entered around door, window,
and other openings. Although most spiders have toxic venom, most spiders cannot harm people.
Those “poisonous” spiders that hurt humans generally spend most of their time in hiding areas.
Common Spiders in and around homes
Funnel weaver spiders: They prefer cool, wet areas, spin funnelshaped webs (no sticky threads), often several-inch-wide, flat
extension covering plants or soil. They live a “lazy life.” They are
predators that sit and wait in the hole of their web, bite the prey on
the web and carry it back into the funnel to be eaten. They feed day
and night on the ground, in most types of vegetation, including
low-growing plants and trees. They rarely come indoors.
Characteristics: They have 6 or 8 eyes, all about the same size,
arranged in 2 horizontal groupings. The body is long oval shaped
and haves a pair of long distinctive silk spinning tubes at the end of
the body.
Funnel weaver spider
Credit to Peter J. Devries
Wolf spiders: Wolf spiders move rapidly, making them seem
aggressive. They actively hunt prey on the ground, day and night.
They do not spin webs but make a small thick web where they rest.
Wolf spiders do not persist indoors but are common “accidental
invaders.” Characteristics: They have 8 eyes of various sizes
arranged in 3 rows— 4 small eyes in front in a straight row, 1 pair
of large eyes in the middle row, and 1 pair of small eyes widely
separated in the rear row (on top of head). Legs are long and hairy.
Wolf spider
Credit to Phil Schappert
Body has black and white markings, similar in looks to funnel web
spiders but lack of the pair of silk-spinning tubes at the end of
body.
Sac spiders (hunting spiders): They are nocturnal, actively hunt
prey at night. Spin silken tubes or sacs in the corners of ceilings
and walls, and behind shelves and pictures where they hide during
the day or retreat after hunting. They do not use webs to capture
prey but can forage large areas in a single night. They may be seen
Sac spider
Credit to Mark Swanson
on walls, ceiling, or ground, at night.
Cobweb weaver spiders: Generally has a soft, round, bulbous
abdomen, and slender legs without spines. They almost always are
found hanging upside down in irregularly spun, sticky webs,
waiting for prey. They are shy, often conceal in a corner of the
web, in a silken tent, or behind debris. Typically they have a
spherical abdomen. Black widow spiders belong to this group.
Black widow spiders mainly dwell outdoors and their webs are
usually found under boards, stones, behind shrubs, where brick or
wood siding extend close to the ground.
Brown recluse spiders: They construct loose irregular web of
very sticky silk that helps trap their prey or to form their egg sacs.
Cobweb spider
Credit to Mike Potter
These spiders occur indoors or outdoors. They prefer dark,
undisturbed and secluded areas. The brown recluse spider has a
violin-shaped pattern on the back of the front body segment. These
spiders have 6 eyes, 3 pairs found in a semi-circular arrangement.
Brown recluse spider
Credit to Sunflower Pest
Solutions
Spider Management
Remember that spiders are primarily beneficial— they eat small insects. A consistent presence of
spiders in structures is often associated with an insect infestation, because spiders cannot survive
long without food. Therefore, reducing insect infestations will also decrease spiders. Pesticide
control is difficult and rarely necessary.
Habitat modifications are the most important tactic for good spider control. Whether found
indoors or outdoors, most spiders have a preference for undisturbed areas.
Outdoors: Remove debris and eliminate places for spider to hide and build their webs by
keeping the area next to the foundation free of trash, leaf litter, heavy vegetation, and other
accumulations of materials. Regularly sweep, mop, hose, or vacuum webs and spiders off
buildings and outdoor areas, especially porches, under eaves, and other likely breeding places
around the home. Outdoor lighting attracts insects, which in turn attracts spiders. If possible,
keep lighting fixtures off structures and away from windows and doorways. Insecticides will not
provide long-term control and should not generally be used against spiders outdoors.
Indoors: Vacuuming spiders can be an effective control technique because their soft bodies
usually do not survive this process. Indoors, a web on which dust has gathered is an old web that
is no longer being used by a spider. Clean up clutter in garages, closets, sheds, basements, and
other storage areas. Dust and vacuum frequently around windows, corners of rooms, shelves,
under furniture, and behind mirrors and pictures. If you see sac spider capsules, remove them.
Individual spiders can also be removed from indoor areas by placing a jar over them and slipping
a piece of paper under the jar that then seals off the opening of the jar when it is lifted up. It is a
good idea to wear gloves when cleaning to avoid accidental bites. Because most spiders enter
houses through small cracks, crevices and other openings, sealing entry points with caulk is the
most permanent solution to spiders wandering inside.
Monitoring spiders: If you are concerned about spiders inside your home, place sticky glue
boards in the rooms where you see spiders, especially on outside walls and in closets and
secluded areas. Take captured spiders to someone who can identify them. Check with your local
extension office. If you have an infestation of brown recluse spiders, you may want to work with
a licensed pest control company— preferably one who has experience treating structures for
brown recluse infestations.
Chemical Control: Typically pesticide control of spiders is difficult unless you actually see the
spider and are able to spray it. There are various insecticides available in retail outlets labeled for
spider control, including pyrethrins, resmethrin, allethrin, or a combination of sodium laural
sulfate and coriander oil. A spider can be killed only if the spray lands directly on the spider. The
spray residual does not have a long-lasting effect. This means a spider can walk over a sprayed
surface a few days (and in many cases, a few hours) after treatment and not be affected. Control
by spraying is only temporary unless accompanied by housekeeping. It is just as easy and less
toxic to crush the spider with a rolled-up newspaper or your shoe or to vacuum it up. Sorptive
dusts containing amorphous silica gel (silica aerogel) and pyrethrins—which can be applied by
professional pest control applicators only— may be useful in certain indoor situations and is
most advantageously used in cracks and crevices and in attics, wall voids, and other enclosed or
unused places