Hobbies And Interests
Typical and Running Crab Spiders
Typical crab spiders and running crab spiders are named for their habit of keeping their front legs raised in the manner of a crab's claws. They are also unusually mobile in moving from side to side. Despite their close resemblance in general outline and behavior, there are important small-scale distinctions between typical and running crab spiders which suggest that they are more distantly related than originally supposed. Typical crab spiders make up the majority of Ohio's crab spider species, with the most common species belonging to the Misumena family of brightly-colored crab spiders. Running crab spiders represent only about a third of the total species, but include the numerous Philodromus family of ground-dwelling crab spiders.
Habits and Habitat
Crab spiders are passive hunters, preferring to remain still and alert in an area where their coloration provides some camouflage. Many crab spiders, such as the three-banded crab spider, are mottled dark grey or brown, and prefer to wait for prey on logs, tree trunks and the litter of the forest floor. Others, such as the white banded-crab spider, are more brightly colored and spend more time on the leaves or flowers of plants. Crab spiders do not spin webs to capture prey, but use silk to produce drag lines and egg sacs.
Pest Status
Crab spiders do not pose a significant nuisance to humans. They are typically found on vegetation and trees, and are not as likely to enter a house as other species. Since Ohio has a great deal of natural vegetation and forested areas, they are not as attracted to flower beds and yards as in more arid regions. Humans are occasionally bitten as a result of leaning against tree trunks harboring camouflaged crab spiders, but the bite is not dangerous and does not cause significant pain beyond the initial pinprick. Bark-dwelling spiders of the Thanatus and Xysticus families are most commonly encountered in this way, due to their camouflaging ability.
Confusion With the Brown Recluse
Some species of crab spider closely resemble the much more venomous brown recluse, which is a less common inhabitant of Ohio. This resemblance is heightened by the fact that brown crab spiders typically wait for prey on logs and tree trunks, while the brown recluse is commonly found around rotting wood and bark. However, the crab spider has eight visible eyes compared to the brown recluse's six, and the leaf-shaped markings of the crab spider do not closely resemble the distinctive fiddle-shaped markings of the brown recluse. The dark brown species of the Thanatus family of running crab spiders are the most common cause of mistaken identity.