What’s The Difference Between Yellow Sac Spiders & Crab Spiders?
What’s The Difference Between Yellow Sac Spiders & Crab Spiders?
Summary: Spiders have shared features across the species, which can make it difficult to tell some of them apart. This blog describes the differences between crab spiders and yellow sac spiders. It starts by discussing the basics of each spider, then going into the risks they bring and the prevention methods people can use for all spiders. Green Pest Services provides reliable spider control for Eastern states.
What is a spider but the creepiest form of natural pest control? We appreciate their bug-heavy diets, but spiders are still unwelcome pests in any home.
Every spider has the same basic qualities that make them arachnids. Their eight eyes, eight legs, venomous fangs, and two body sections are shared features. Each species also has unique abilities and physical features that set it apart — for the most part.
Two spiders that have similar habits and preferences are the crab spider and yellow sac spider. But what sets them apart from each other? Let’s find out by learning about each spider and their frustrating habits!
Crab Spider
Crab spiders are:
- Broad and flat
- Short-legged with 2 long front legs
- Hunting spiders
- About .3 inches long
- White, yellow, or green in color
These spiders are quite the talented pest. They can change their colors to blend in with their environment, similar to a praying mantis. Crab spiders even contort their bodies to mimic the shape of the flower that they’re sitting on! They camouflage themselves and wait for their prey, then pounce and capture the insect with their front legs.
Although crab spiders don’t have the best vision, they can detect nearby movement. They usually live near flowers because they have a wide variety of prey to choose from, such as bees and flies. Crab spiders place their egg sacs on flowers in the fall so that the hatched eggs have immediate food in the spring.
The most interesting feature of crab spiders is how they move. True to their name, these spiders can walk side-to-side. They also move forwards and backwards — like any spider — but the side-to-side movement comes in handy when dodging hungry predators. If you see a sideways-walking arachnid, you’ve found yourself a crab spider!
Yellow Sac Spider
Yellow sac spiders are:
- Rounder
- Long-legged
- Hunting spiders
- About 1/4 of an inch long
- Yellow or cream in color
If the yellow sac spider finds a dark corner, you can bet that it’ll hide there as long as possible. These arachnids conceal themselves in between hunting prey, so they’re usually found under rocks, leaf litter, and clutter. They stay hidden during the day, then come out at night to hunt the helpless insects that thought it was safe to do their own nighttime activities.
Similar to crab spiders, yellow sac spiders produce their egg sacs in the fall and stay nearby to guard their offspring until the spring. Each sac contains 30 to 48 eggs, so if the mother put the sac indoors, an infestation is imminent. These spiders don’t usually stay inside on purpose, but a warm house is much better than the freezing weather outside!
Yellow sac spiders live for about a year, and they make use of their short time by devouring a lot of insects. Between their quick reflexes and their strong venom, these spiders are a formidable foe to small pests. They’re also not afraid to get near us, so keep an eye out for these spiders when you’re working in the yard!
Are They Dangerous?
Now for the question on everyone’s minds: are these spiders dangerous?
Well, yes and no. They’re not the most dangerous spiders in America. That title belongs to the black widow and brown recluse. But yellow sac spiders and crab spiders both have the ability to bite us, so they aren’t harmless either.
Since both spiders prefer to stay outdoors, you only run the risk of getting bit if you disturb the adults or their egg sacs. They’re still defensive when they’re indoors, so keep an eye out for these arachnids in your home.
Crab spiders are the less worrisome of the two. Their venom isn’t fatal to human, so a bite won’t typically warrant a trip to the hospital. Plus, they prefer to avoid us at all costs when we get too close.
On the other hand, yellow sac spiders can deliver a nasty, blistering bite. Most bites aren’t dangerous, but some people have similar symptoms to a black widow bite. Fever, chills, aches, and nausea are among the most common. Luckily, this bite is completely treatable. If you’re bitten by this spider and have symptoms, please seek medical attention immediately.
Spider Prevention Tips
If the thought of these spiders makes you squirm, fear not! We have some great prevention tips that work against any type of spider plaguing your home. It’s a good idea to implement these methods year-round because spiders are active in every season, as long as they have a warm shelter.
Our best spider prevention tips include:
- Trim back plants and trees. Cut back plants, bushes, and tree limbs from the house by at least one foot.
- Seal cracks. Inspect the house exterior for cracks and gaps, and seal any that you find with waterproof caulk.
- Remove leaf litter. Don’t let fallen leaves and organic debris clutter your yard for too long. Use a rake or your hands (with strong work gloves!) to pick it up.
- Eliminate clutter. Keep your storage spaces as organized and tidy as you can. This includes the garage, attic, and closets.
- Check door & window seals. Replace any weather-proof seals that are cracked or loose. Check each seal throughout the colder seasons to ensure they’re still good.
- Remove spiderwebs. Spiders can reuse old webs as new homes, so use a duster or vacuum to remove spiderwebs around the house.
- Solve other pest problems. Spiders invade spaces that have a reliable food source. If you start seeing a lot of spiders, inspect your home for any hidden pest problems.
Get Rid Of Spiders With Green!
Whether you’re battling black widows or contending with crab spiders, Green Pest Services is always prepared to solve your arachnid issues! Our licensed technicians start every service by checking the property for any pest activity, then create a treatment plan that targets the current pests and prevents them from returning.
Instead of wasting time with temporary treatments, we provide long-term solutions for your pest concerns. Your complete satisfaction with our services is our top priority. Our team of experts is happy to address every question and concern you have along the way. For a free quote on our reliable services, contact us today!
Citations
Crab spiders (family Thomisidae). Northern Virginia Bird Alliance. Retrieved January 6, 2025, from https://www.nvbirdalliance.org/aah-sanctuary-species-crab-spiders
Fake, E.C. (n.d.). Your winter spider visitors may not be perfect guests. Fairfax County Master Gardners. Available at https://fairfaxgardening.org/spiders/ (Accessed on January 7, 2025).
Understanding crab spiders. (n.d.). Terminix. Retrieved January 7, 2025, from https://www.terminix.com/spiders/crab/
Yellow sac spider. (n.d.). Terminix. Retrieved January 6, 2025, from https://www.terminix.com/spiders/yellow-sac/
Yellow sac spiders. (n.d.). Michigan State University. Retrieved January 6, 2025, from https://www.canr.msu.edu/resources/yellow-sac-spiders
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