A pseudoscorpion, (Pseudoscorpiones).
Photo by Drees.
Common Name: Pseudoscorpion
Scientific Name: Varies
Order: Pseudoscorpiones
Description: The body of pseudoscorpions is divided into two general regions; the head-thorax (cephalothorax) and the abdomen. The body and appendages have many setae. The cephalothorax is covered by a shield or carapace that is not segmented. There is usually one or more pairs of eyes on the edge of the cephalothorax. There are six conspicuous appendages on the cephalothorax; the chelicerae, the palps, and 4 pairs of walking legs. Chelicerae are short and have a clasping mechanism with a fixed and a movable finger. The pedipalps are longer and have a claw that resembles that of a scorpion. The abdomen has 12 segments but the last two are reduced and inconspicuous. They do not have a long tail like scorpions and they do not sting. Pseudoscorpions are quite small with a body length generally under 3 mm. Thirty three species exist in Texas.
Life Cycle: Pseudoscorpions have spinnerets and produce silk that is used to construct nests and temporary sheets for sperm transfer. Females usually produce only 3 or 4 clutches of eggs but some produce up to 30 eggs per clutch. Immatures hatch from eggs carried by the female. There are three additional immature stages which are free living, followed by the adult stage. Although data is sparse, adults are apparently long lived, probably surviving for 6 months to two years.
Habitat, Food Source(s), Damage: Pseudoscorpions are predators that feed on a variety of small insects and other arthropods. Pseudoscorpions can be found in a wide variety of habitats and habitat by species preference is well documented. They can be found in ground cover, leaf litter, in rotten logs, under bark, in bogs, swamps, in rock outcrops, caves, and homes. None are known to be external parasites (ectoparasites) but they can be found in bird and rodent nests where they feed on arthropods in the nests. They are sometimes found on beetles or large insects where they apparently feed on mites.
Pest Status: Rarely observed; not pests and medically harmless.
For additional information, contact your local Texas A&M AgriLife Extension Service agent or search for other state Extension offices.
Literature: Hoff 1949; Weygoldt 1969.
A pseudoscorpion, (Pseudoscorpiones).
Photo by Drees.