Have you been bitten by a crab spider or is one lurking around your living area? First off, don’t panic; crab spiders’ venom are not poisonous to you (unless you are a bee or unless you happen to be allergic). And if you don’t know if you are dealing with a crab spider (Thomisidae), check to see if they look like a crab in that their front legs are held up and out, their 4 – 10mm bodies are a bit flatter than other spiders, and, like a crab, they are walking sideways. Also check to see if they look a bit neon in color (yellow, green or orange) or sometimes white or brown. You probably should also stop looking for cobwebs; these crabby walkers tend to wait on foliage and on the grounds of gardens for prey.
Although you may not want to hear this, crab spiders are considered helpful for humans as they kill those pesky flies, mosquitoes, moths and other insects (like we do!), however not many people want crab spiders habituating with them. What these crab spiders really love, however, are flowers (hence their bright colors). Like a chameleon, the crab spider can change her color to camouflage itself into the flower she is waiting on to ambush an unsuspecting insect and to hide from other predators.
The crab spider will stay put in its hunting spot for days or even weeks, sometimes changing color with it’s surroundings. When it sees a living meal it can catch, it will drop a silk line to hunt, similar to a fisherman. Again, the crab spider can bite and will bite a human, but its venom is not harmful or poisonous.
If a crab spider is found in your house, it’s probably a mistake on its part for navigation. The crab spider most likely wants to be on a leaf, under a piece of bark, on a flower or in the crevasse of a tree trunk in your garden. If you’ve noticed a brown-speckled, flat, crab-legged spider hanging around and need to test it to see what kind it is, gently poke it with a long stick and watch to see if it widens those long front legs and moves sideways. If it does, that will be a crab spider.