Missouri Spiders

Brown Recluse Spider

There are more than 300 different types of spiders in Missouri. Orb weavers, crab spiders, jumping spiders, and wolf spiders are among the most frequent types. The proportions of their bodies, the make-up of their limbs, and the placement of their eyes all help to set these groupings apart. Tarantulas are uncommon in Missouri, but they have been spotted on occasion. Only two spider species in Missouri, the brown recluse and the black widow, are a risk to human health. 

Despite widespread belief to the contrary, most spiders pose little threat to human health. The first reaction of most spiders when they feel a vibration is to run and hide. They aren’t dangerous until provoked, and they rarely bite even then. Most people get bitten by spiders when they are squished while hiding in their clothing or shoes.

Black Widow

One of two poisonous spiders found in Missouri is the black widow. A red hourglass marking can be seen on the underside of the female black widow’s abdomen. The abdomen typically dwarfs the head and chest. The males are noticeably smaller than the females, and they have a variety of yellow and red markings all over their bodies. Similar marks can be seen on younger black widow spiders. Females are the only ones with venom.

Black widow spiders are nocturnal, solitary, and fearful insects that like to hide out in dark, undisturbed places under rubbish, litter, boards, or rocks. They also populate seldom-visited structures like basements, crawl spaces, and attics. Black widow spiders are nocturnal and will not leave their webs until they are disturbed. Black widow spider bites typically occur when people accidentally come into contact with the spider’s web or when the spider is pinned against their skin.

The venom of the black widow spider is toxic to the neurological system. Pain at the bite site, fainting, nausea, impaired vision, and trouble breathing have all been linked to black widow spider bites. Seek emergency medical assistance if you are bitten by a black widow spider. Black widow bites almost never prove fatal, and the majority of victims make full recoveries quickly.

Black widow spiders are notorious for creating sloppy, asymmetrical webs close to the ground. Because of the potential danger posed by black widow spider bites, prompt action should be taken at the first sign of an infestation.

Brown Recluse

So named because of its shy nature and pale brown coloring, you may find the Brown Recluse in basements, storage closets, and woodpiles or any other damp, crowded, and undisturbed place. The brown recluse spider was detected in roughly 70% of Missouri houses in one survey.

The recluse spider is a dangerous species native to the Southeast and Midwestern United States. A violin-shaped marking may be seen on the back of this little spider, which can be any shade of brown. The brown recluse spider is nocturnal and reclusive. Spider bites typically occur when victims put on gloves or shoes where spiders have been hiding. Children, the elderly, and those with prior medical issues are most vulnerable to a life-threatening allergic reaction following a bite. In the event that you suspect a bite from a brown recluse spider, it is important to get medical assistance at once.

The brown recluse spider’s venom is deadly to both humans and pets. The severity of a brown recluse bite is proportional to the venom dose and the susceptibility of the victim. Sensitive people may have a severe reaction complete with a stinging sensation, severe pain, swelling, and a white blister on the bitten area. The surrounding tissue may slough off and die, creating a deep ulcerated sore after a bite. The average reaction is minimal and limited to an area smaller than a dime. On very rare occasions the ulcer can spread to other areas. Immediate medical intervention can avert life-threatening responses and mitigate the effect of a bite from a brown recluse. Brown recluse bites are often painful but almost never fatal.

Spiders are reviled and misunderstood, but they serve an essential ecological function. They prey on nuisance  insects and their presence aids in reducing pest numbers. Although certain spiders are dangerous due to their venom, most are completely safe around humans. Most spider species aid people by controlling bug populations in our homes and gardens. Spiders perform a crucial function in our ecosystem, and we should learn to respect them for it.

In Missouri, wolf spiders and daddy longlegs are frequent house guests. Although they may look scary, daddy longlegs are actually very useful and should be accepted. Wolf spiders prey on the brown recluse and the black widow. Humans need not worry about being harmed by daddy longlegs or wolf spiders.

PestWorld.org. “Spiders.” PestWorld.org, 2023, https://www.pestworld.org/pest-guide/spiders/

Houseman, Richard M., Department of Entomology. “Spiders.” Extension.missouri.edu, University of Missouri Extension, 2023, https://extension.missouri.edu/g7386