Encyclopedia Article

Description of pseudoscorpions

Pseudoscorpions are a common arachnid closely related to scorpions, mites, ticks and spiders, but they usually go unnoticed because of their small size. When they are noticed is when they accidentally invade homes and wander into sight.

They are not a household pest because they cannot bite or sting and they do not attack the house structure, furniture or occupants. They may be an annoying nuisance, usually during the spring and summer, as an occasional "accidental invader."

Damage caused by pseudoscorpions

Only rarely are they a chronic pest problem. Like other arachnids, pseudoscorpions have 8 legs. In addition, they have a pair of enormous pincers (called pedipalps) on the front of the body that gives them a strong resemblance to the true scorpions.

Unlike scorpions, pseudoscorpions are very small, usually less than 5 mm long, and they have no sting on the end of their flat, oval abdomens. Natural habitats for pseudoscorpions include under leaf litter and mulch, in moss, under stones and beneath tree bark. They have also been reported in bird nests and between siding boards of buildings.

Because they are sometimes found among books, they are also known as "book scorpions." Pseudoscorpions are predaceous and therefore beneficial. They feed on other arthropods, particularly small insects and mites.

Management of pseudoscorpions

Special treatments for control of pseudoscorpions are usually not warranted. Only in a persistent infestation should control be attempted. It would be difficult to prevent all invasion by pseudoscorpions but sealing gaps, cracks and other points of entry may help exclude them.