How to Identify Missouri Spiders

Six-Spotted Fishing Spider

There are many different types of spiders living in the southern regions of the United States, and some are even native to Missouri. Some of them are poisonous, some of them are harmless, and some of them help to lower the number of insect pests living around our houses. However, if you get a visit from one of these eight-legged guardians, it is important to know how to identify different types of spiders so that we can tell which ones are dangerous and which ones can be calmly moved outside.

Difficulty:

Moderately Easy

Instructions

1. Judge how large the spider is by looking at the length of its body and the length of its legs.

2. Check to see if the spider has a body that is 1 inch or more in length without including the leg span. If it does, the spider is most likely a six-spotted fishing spider, tarantula or black and yellow garden spider. If the spider has a body that is less than 1 inch long without including the leg span, skip to Step 6.

3. Six-Spotted Fishing Spider

   Estimate how long the spider's leg span is. If the leg span is around 3 inches long and the spider is a light brown color with light and dark gray markings, it could be a six-spotted fishing spider. These spiders enjoy living near water or dark, damp places. They can run across water to hunt for prey, they do not maintain a web, and they are just poisonous enough to cause minor redness and necrosis near their bites.

4. Tarantula

   Check for whether the spider is a tarantula. If the spider has a leg span close to 2 or 3 inches in length and it is dark brown in color with a very hairy exterior, it could be a tarantula. Keep in mind that the spider may be smaller and still be a tarantula if it is not full grown. Tarantulas pose no threat to humans, which is why many people choose to keep them as pets.

5. Black and Yellow Garden Spider

   Check to see if the leg span of the spider is about 2 1/2 inches long, and look for yellow and black markings with a white area near the head. If your spider fits this description, it is likely to be a black and yellow garden spider. Bites result in only mild itching and swelling for a couple days, though it is believed its bites could inject a very small amount of neurotoxin as well.

6. For smaller spiders, do not attempt to measure the leg span. It is much easier to tell these spiders apart by looking for distinct traits or markings. In Missouri, these spiders could be bold jumping spiders, black widows, brown recluse spiders, ridge-faced flower spiders, funnel-web spiders or filmy dome spiders.

7. Bold Jumping Spider

   Look carefully at the spider to see if it is black with a white marking on its back. Also, if the spider is jumping around, this is another big sign that the spider you are looking at is a bold jumping spider. These spiders are aggressive and spunky, with a bite that hurts but lacks any dangerous poison.

8. Black Widow

   Look at the coloration of the spider and see if it is black with a red hourglass-shaped pattern on its underbelly. If it is, it is almost certainly a black widow. These spiders have extremely poisonous venom and commonly hang upside down from their rough, messy webs.

9. Brown Recluse Spider

   Check to see if the spider is brown and smooth with a violin-shaped pattern on its back. If it fits this description, the spider is most likely a brown recluse spider. These spiders are very poisonous, aggressive, and they enjoy hiding in soft places like the arms and legs of clothing, bedding, or pillows more than any other spider in Missouri.

10. Ridge-Faced Flower Spider

    Check to see if the spider is brightly colored and found among a cluster of flowers. If it is, the spider is most likely a ridge-faced flower spider. These spiders are a type of crab spider, and they will wait for unsuspecting bees or butterflies to land near the clusters of flowers. Ridge-faced flower spiders are not dangerous to humans.

11. Funnel-Web Spider

    Look for a nearby burrow and a funnel-shaped web leading or partially leading to the burrow. If you can find such a burrow, the spider is probably a funnel-web spider. These spiders are harmless to humans and are great at catching pests outside of your home. They are rarely seen indoors.

12. Filmy Dome Spider

    Examine the spider for a yellow and black coloration, and see if it is near on hanging from a dome-shaped web. If it is, you most likely have a filmy dome spider on your hands. These spiders are not dangerous unless you are an insect.

13. If none of these steps led you to an identification of the spider in question, try sending a picture to a biologist in the area or contact a poison control center if bitten. You may also try an online resource such as the one listed under Resources below.

Tips & Warnings

• Spider identification is tricky business if you squish your eight-legged visitor. Try to avoid pounding a spider to death if you would like to know what it was later.

• Always seek medical attention if bitten by a poisonous spider. Serious symptoms may not start appearing for as long as 8 hours after the initial bite. If you can, try to catch the spider that bit you so that you can present it to medical officials for identification.

Resources

• Additional Information in a Spider Database