Chelifer cancroides
ORDER
Pseudoscorpionida
FAMILY
Cheliferidae
TAXONOMY
Chelifer cancroides Linnaeus, 1758.
OTHER COMMON NAMES
English: House scorpion.
PHYSICAL CHARACTERISTICS
Slightly smaller than scorpions, with a length of 0.10–0.18 in (2.6–4.5 mm). Does not possess stinging tail, has enlarged pedipalps, and transmits spermatophore in complex courtships. Cephalothorax (also called scutum) contains six pairs of appendages: chelicerae, palpal chelae (two well-developed claws), and four pairs of legs. Femora of legs one and two are different in general structure, especially with regards to joints, from femora of legs three and four. Cephalothorax is olive-brown to dark red. Palpal chelae (reduced claws near mouth) consist of large bulbous hand, with one fixed finger and one moveable finger. Moveable finger does not have edge but instead has a subapical lobe. Accessory teeth are not contained on chelel fingers. Opisthosomal tergites are pale brown to olive-green, with darker spots. Pedipalps are tawny brown to reddish brown, with some olive coloration. Venom apparatus is well developed in both fingers of palpal chela. Cheliceral flagellum consists of three long, straight setae. Complex internal genitalia of males are heavily sclerotized. Spermathecae of females are short, rounded sacs, with sclerotic plates.
DISTRIBUTION
Throughout most of Europe.
HABITAT
Usually found under stones, beneath bark of trees, or in vegetable debris, but can also be found in human habitations and outbuildings such as stables, barns, grain stores, factories, and houses, and seems to move wherever humans locate. Often found in old books (thus, its common name). Prefers warmer regions of the world.
BEHAVIOR
Often found in groups of several dozens. Females often use pedipalps to hold onto flying insects such as houseflies to be carried to where it wants to go. Males do not commonly use this method of transportation (called phoresy). Palpal chelae are mainly used for defense/fighting, acquisition of prey, and moving small objects (like sand grains) to make nests. A small, spherical silken chamber (or cocoon) is built for hibernation during winter months, and for molting.
FEEDING ECOLOGY AND DIET
Carnivore and insectivore, eating animal tissue and arthropods such as small insects, mites, and lice. Often secures itself underneath wings of large tropical beetles to feed on parasitic mites. It may also do similar actions to legs of houseflies and other two-winged insects. Generally will grab prey with pedipalps, immobilize prey with poison glands, rip it up with chelicerae, and suck fluids from body.
REPRODUCTIVE BIOLOGY
Complex courtship and mating behaviors from both males and females, including extension of ramshorn organs of male and dance-like behavior by pair. Reproduction is through spermatophore: adult males use modified first legs to expel mass of spermatozoa. Females are oviparous; they will build nest by secreting a "brood sac" attached to body, where she will nourish young. Generally, 16–30 offspring are produced from each reproductive cycle; they will depart the mother's protection soon after hatching, after reaching a fixed, definite shape. Sexual maturity is reached in 1–2 years.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Often eats lice that have infected human hair. Also feeds on other creatures seen as pests for humans, such as mites and ants. It seems to offer little direct benefit to humans, although little is really known about its contribution to human life.
