Year of the Spider: Crab Spiders

Red-banded Crab Spider - Misumenoides formosipes.jpg

Continuing with the Year of the Spider, the next spider spotlight shines on the crab spiders. These members of the Philodromidae and Thomisidae family get their name from their crab-like appearance. Female crab spiders, like other spider species, are larger than their male counterparts. Usually ranging from ½- to ¾-inches in size, crab spiders are smaller than some of our other spider species. The largest of our crab spider species can fit on a quarter, but what they lack in size, they make up for in beauty. Crab spiders, like jumping spiders, have beautiful markings that range from earth tones tan to bright yellows and reds. These markings, while bright, are used to camouflage crab spiders in their pursuit of food. Different than traditional web-building spiders, crab spiders do not use webs to entrap their prey. They use camouflage to hide among flowers in wait of their prey. Crab spiders are often colored to blend in with the whites and yellows of many species of flowers that serve as hunting platforms. Camouflaged against the flower petals, crab spiders lay in wait as various pollinators fly up to feed on the blossoms. As prey approaches, the crab spider pounces, grasping the prey and biting the back of the neck of the insect. This paralyzes the insect and allows the crab spider to eat its meal more easily. Crab spiders are opportunistic feeders and will eat any insect that comes to the flower it is hunting on. Their prey can range from bees and wasps, to the more common moths and butterflies. Because crab spiders spend their time hunting on and around flowers, they are most often found in open fields, meadows, savannahs and other places that support a diversity of flower species.

The life cycle of a crab spider is relatively short; measured in months, not years. The adults mature in late summer or early autumn and mate shortly after. The flat egg sacs, containing up to 100 eggs, are laid on nearby sticks, stems or twigs. A dedicated mother, the female crab spider will guard their egg sacs until their deaths. The young will overwinter in the egg sac and emerge in the spring, feeding through the summer until maturity in late summer, when the process will start again.

Crab spiders are arguably among the prettiest spiders found in North Carolina. They can be readily seen with a little bit of effort and the ability to slow down and look for them. So, the next time you find you find yourself admiring a pretty bloom, lean a little closer and look a little harder. The flower you may be enjoying, may in fact have a predator waiting for its next meal to fly up.