Crab Spider

Crab Spider Scientific Name: Ozyptila praticola

What does a Crab Spider look like?

Crab Spider

Crab Spider

Not to be confused with the spider crab, crab spiders are so named for the way they carry their two front pairs of legs (which are much longer than the back two pairs). Or maybe it’s the fact that they “scuttle” both front and backwards as well as side to side. It could also be that the bodies of the crab spider, like a spider crab, are angular and flattened. More likely, it’s a combination of all these traits that gives the crab spider its name. Male crab spiders are approximately 1/8 of an inch long; females larger – ¼ to 3/8 of an inch long. The color of a crab spider widely varies, sometimes dependent on the color of flower they frequent, but most are brown with red and white markings on the sides of their abdomens; some species may also be yellow, green, grey or even pink.

Where does the Crab Spider live, and what does it eat?

Over 2000 species of the crab spider exist and they are found on every continent but Antarctica. The most common species of crab spider, though, are in North America.

Crab spiders do not trap prey in a web, but may drop a silk thread line for protective or reproductive purposes. Some species of crab spiders wander around hunting their prey, but most are passive hunters; they await prey near food sources then grab and eat it. Some species of the crab spider can actually camouflage to the color of a fruit or flower in order to get close enough to their prey to attack.  Crab spiders are most commonly found in gardens, meadows, fields, forests, and shrubbery. If entrance points are available, the crab spider may occasionally enter a home but prefer to remain outdoors on flowers. The crab spider may also be brought indoors on a potted plant or fresh cut flowers.

These spiders prey on insects that land on flowers like bees, wasps, and butterflies. Acting as a natural pest control, crab spiders also feed on mosquitoes, flies, and moths.

Are Crab Spiders venomous?

Crab spiders may attack humans if there is a perceived threat, or when squeezed or pinched against human skin. These spiders are not aggressive, however, and will rarely bite a human. Additionally, crab spiders are not likely to be in places that are inhabited by humans. The bite of a Crab spider is not venomous, but the bite can on occasion cause an allergic reaction. In this case medical attention should be sought. Symptoms of such a reaction may include systemic symptoms like headaches, nausea, or vomiting.

The bite of a crab spider can actually exhibit venomous-like qualities for certain of its prey, such as bees.

How are Crab Spider bites treated?

The best thing to do is remain calm. Crab spider bites are not dangerous and can be treated easily. Most crab spider bites exhibit no symptoms, but if they do there are some simple steps to take to reduce discomfort. To help with pain and swelling, apply an ice pack and avoid abrupt movements. Elevate the bite if it is on an arm or leg.

The Crab spider is a harmless spider that may actually be a very beneficial part of your garden ecosystem. A predator to garden pests like mosquitoes and flies, you can put Crab spiders to good use. If Crab spiders invade your home, however, their webs can be obtrusive and bites are known to occur. Seek control of the Crab spider only when you believe there is an infestation or numbers are large.