While California boasts beautiful scenery and weather year-round, it is also home to a large number of spider species. While most of these spiders are nothing more than a nuisance or something that sends a chill up your spine when you see them crawling across your path, California is home to some venomous spider species that can pose a medical concern.
Here at Insight Pest Management, we have an in-depth knowledge of the common spiders in Southern California, and we hope this information can help you identify your spider problems. The good news is residential pest control can help keep your home spider-free.
- California has numerous spider species, some of which are venomous.
- Management has knowledge of common spiders in Southern California.
- American house spiders help control insect populations and are commonly found indoors and outdoors.
- Western black widow spiders are highly venomous to humans and prefer dark areas.
- Brown widows and false black widows are less venomous than black widows, but still can cause pain and discomfort.
American house spider
The American house spider, also known as the common house spider, is a comb-footed spider known most for its cobwebs that are iconic at Halloween. These spiders are known to help control insect populations and are frequently found in the corners of your floors and ceilings and under eaves and overhangs outside.
- Scientific name: Parasteatoda tepidariorum
- Physical appearance: These spiders have a bulbous abdomen that is brown in color, often speckled with white and dark patches or lines. It has long, skinny legs covered in comb-like hairs.
- Habitat: Commonly found in corners or floors, ceilings, and windows indoors and under eaves and overhangs outdoors. Known for their characteristic cobweb.
- Diet: Other insects, such as flies, cockroaches, earwigs, mosquitoes, moths, and ants.
- Toxicity (Danger Level): House spiders are not venomous, but they can bite. A bite may feel like a bee sting and cause redness and swelling.
Western black widow spider
The Western black widow spider is best known for its characteristic jet-black body and red hourglass shape on the abdomen. Female black widow spiders are highly venomous to humans. However, death from a slack widow bite is very rare. While these spiders do not want to interact with humans, they tend to hide in areas where you may come into contact with them, such as boxes, inside shoes, or in bathtubs and toilets, looking for moisture. You are more likely to see a female black widow as males are eaten after mating.
- Scientific name: Latrodectus hesperus
- Physical appearance: Shiny black body with distinct red hourglass on the abdomen. Females have a ½ inch body size (not including the legs) while males are roughly half the size.
- Habitat: Black widows prefer to nest near the ground in dark areas that are not normally frequented by humans, such as wood piles and under low shrubs. Indoors, they will look for dark, undisturbed locations, such as storage areas.
- Diet: Insects and other spiders
- Toxicity (Danger Level): Extremely potent venom that, when bitten, can cause symptoms such as muscle and chest pain, breathing and speech difficulty, swelling of the extremities and eyelids, cramping, nausea, body discomfort, restlessness, and body sweats. While the venom spreads quickly, a bite does not usually deliver enough to provide a fatal dose in adults. Children can have more complications. Symptoms usually improve within a few days but can last weeks.
Often confused with daddy long-legs, cellar spiders have small bodies with very long legs that prefer to spin their loose, irregular webs high in doorways to catch prey. When disturbed, these spiders shake in order to blur their appearance. This shaking often vibrates the entire web. Unlike other spiders that remove trapped prey or remove old webs to create new ones, cellar spiders add more webbing to existing webs, often creating excessively thick and noticeable webs over time.
- Scientific name: Holocnemus pluchei or Pholcus phalangioides
- Physical appearance: Oval light brown, grey, or yellow abdomen with clear, white, or marbled patterns and long, thin legs.
- Habitat: These spiders look for dark, damp areas and are drawn to places such as basements or cellars.
- Diet: Insects
- Toxicity (Danger Level): Non-venomous and not known to bite humans.
Brown widow spider
The Brown widow spider is not a native spider to Southern California and only became established in the early 2000s. While this new spider resident has venom as toxic as its black widow counterpart, it is unable to inject as much venom through a bite, making it very unlikely to cause symptoms greater than a painful bite and a red spot.
- Scientific name: Latrodectus geometricus
- Physical appearance: Unlike the characteristic look of a Black Widow, the Brown Widow is mostly mottled tan and brown with black accents. It does, however, have an hourglass shape on the abdomen, but the color is a muted orange and not as distinct.
- Habitat: Similar to black widows, the brown widow prefers to nest near the ground in dark areas that are not normally frequented by humans, such as wood piles and under low shrubs. Indoors, they will look for dark, undisturbed locations, such as storage areas.
- Diet: Insects and other spiders
- Toxicity (Danger Level): While their venom is as toxic as a Black Widow, they are unable to deliver a toxic bite to humans, typically causing pain similar to a bee sting and localized redness.
False black widow
Also known as the cupboard spider or the dark comb-footed spider, the false black widow has a similar body shape to the black widow. While not as venomous as the black widow, it can still cause a bite that can cause significant pain but is not considered medically significant.
- Scientific name: Steatoda grossa
- Physical appearance: Similar body shape to the black widow with a body color ranging from brown to purplish black. The main difference is you will not see a red hourglass shape on the underside of the abdomen.
- Habitat: They tend to build webs in building and doorway corners.
- Diet: Other insects and spiders, with their preferred diet being Black Widows
- Toxicity (Danger Level): A bite can cause swelling and blistering in the area and may cause discomfort and a fever for a couple of days but is not severe and has no long-term effects.
The European spider, also known as the noble false widow spider, is a relatively new spider to Southern California. Originally found in England, Spain, and other areas of Europe, the European spider was first found in Ventura County in 2011 while researchers were looking for the invasive Brown Widow.
- Scientific name: Steatoda nobilis
- Physical appearance: Same size as a Black Widow but with a white or tan band on the front part of the abdomen and the back. This white banding can often look like a house with a domed roof, and legs are reddish brown.
- Habitat: They can be found both indoors and outdoors.
- Diet: Insects
- Toxicity (Danger Level): Not considered to have venom toxicity
One of the most intimidating spiders in California is the wolf spider. These large and hairy spiders are often mistaken for Tarantulas. These spiders do not spin webs but rather chase and hunt down their prey and are most commonly found on the ground.
- Scientific name: Lycosidae spp.
- Physical appearance: Gray, brown, black, or tan in color with darker markings and stripes. These spiders have a very distinct eye pattern, with two medium-sized eyes on the top row, two large eyes in the middle row, and a bottom row of four small eyes. They can grow up to one and a half inches, not including the legs.
- Habitat: Outside, Wolf spiders look for areas on the ground to camouflage, such as under plants, under rocks, or in wood piles and logs. They may also dig burrows to hide and wait for prey. Indoors, they will hide in doorways and windows, among houseplants, and in closets.
- Diet: Insects and small vertebrates, such as amphibians and reptiles.
- Toxicity (Danger Level): Wolf spiders do have venom, but it does not pose a threat to humans. Bites may cause redness or swelling.
Similar to the wolf spider, the fishing spider can be just as large and sport similar markings. The difference is these spiders are most often found near bodies of water and have been known to eat small fish. While they have a larger size, they are still able to walk on water, making it easier for them to hunt their natural diet of aquatic insects.
- Scientific name: Dolomedes vittatus
- Physical appearance: These spiders are large in size, brown with a white border and dark spot on the head, hairy, and move very quickly.
- Habitat: Near the water. They are often found along rivers and streams and will often take shelter in boats and boathouses.
- Diet: Water insects and small fish
Toxicity (Danger Level): While they can bite, they pose no danger to humans.
California is home to a number of tarantula species, including the California ebony tarantula, most common in Ventura County. Unlike many other spiders with short life spans, female tarantulas can live up to 25 years. Males, however, take 8 to 12 years to mature before searching for a mate and dying a few months later.
- Scientific name: Theraphosidae
- Physical appearance: Dark brown and ebony to light beige in color, with females having a leg span over up to 5 inches.
- Habitat: These spiders spend most of their time in burrows waiting for prey to approach.
- Diet: Insects and small lizards
- Toxicity (Danger Level): Tarantulas are venous, but the venom is typical to that of a bee sting. However, they do have large fangs and can give a painful bite if they are disturbed.
Similar to the brown recluse that is not native to California, the desert recluse is similar in appearance and toxicity. The good news, as their name implies, they are reclusive and nocturnal, so you aren’t as likely to run into these spiders.
- Scientific name: Loxosceles deserta
- Physical appearance: Tan or yellowish-tan in color with a light brown abdomen. They have a fiddle-shaped marking on the body and have six eyes instead of eight, arranged in pairs of three. Body size is around ½ inch with full leg span ranging between 1.5 to 2 inches.
- Habitat: Mostly found outdoors in dense vegetation and do not do well indoors.
- Diet: Insects
- Toxicity (Danger Level): Necrotic in nature, the venom of the Desert Recluse can damage tissue around the area of the bite, as well as cause symptoms such as nausea, fever, abdominal cramps, joint pain, and headache.
Silver garden orb weaver
This orb-weaver spider is known for its UV reflecting bodies and silk that spins beautifully outdoors webs that attract pollinating insects by imitating the characteristics of flowers. This spider thrives in dry and humid environments and is often found on prickly-pear plants.
- Scientific name: Argiope argentata
- Physical appearance: Covered in silvery hairs that give a metallic and white appearance that reflects UV light. The underside of the abdomen is a dark brown with a yellow stripe.
- Habitat: These spiders are found throughout Southern California, Argentina, and Chile.
- Diet: Moths, butterflies, and other insects.
- Toxicity (Danger Level): Harmless to humans
You don’t have to share your home with spiders
Southern California is home to a diverse population of spiders, and while most of the spiders you will encounter are likely to be more afraid of you, some with a bite can pack a punch. The good news is, that you don’t have to share your home or yard with spiders. The team of professionals at Insight Pest Management offers spider control that can help. To learn more about how we can send the spiders packing, request an appointment today!