The Bug Box: Pseudoscorpions

Colorado State University

Yale University

This bug is creeping around your property. He may be friend or foe.

Name: Order Pseudoscorpionida

Alias: Pseudoscorpions. There are many different species in the United States. Mostly they go unnoticed as they are very small, being 1/16th to 1/8th of an inch long. Pseudoscorpions are arachnids and are closely related to mites, ticks and spiders and have eight legs and two general body regions: the head-thorax (cephalothorax) and the abdomen. They have front claws that closely resemble true scorpions with which they grab their prey. The claws, or pedapalps, have a poison gland that they use in subduing their prey. They can walk backwards as well as forwards. When found in the home, they are generally around moisture sources. They feed on a variety of small insects and other arthropods. Pseudoscorpions can be found in many different habitats including ground cover, leaf litter, in rotten logs, under bark, in bogs, swamps, rock outcroppings and caves, nests of birds and rodents and homes. They are even found on larger insects where they apparently feed on mites. Pseudoscorpions use their spinnerets to produce silk that is used to make temporary nests and sheets for sperm transfer. The female will produce three to four clutches of eggs with up to 30 eggs per clutch. The eggs, which are carried by the female, hatch into imatures that ride on their mother’s back for a short time and then go through three additional stages before maturing into adults. Adults evidently live from about six months to three or more years.

Crimes: These guys are rarely observed and despite their menacing looks they are medically harmless to people.

Redeeming Qualities: They are predators on other insects and arthropods and considered one of the good guys.

Sentence: Control measures are seldom needed. Simply transfer them outside if found indoors. Eliminating food sources inside the home will discourage them from setting up shop indoors.


For more information on dangerous and beneficial bugs, call agent Wayne Jones at the Bonneville County Extension Office at 529-1390.