Rhaphidophoridae
The orthopteran family Rhaphidophoridae of the suborder Ensifera has a worldwide distribution.[1] Common names for these insects include the cave wētā, cave crickets, camelback crickets, camel crickets, spider crickets (sometimes shortened to "criders", or "land shrimp" or "sprickets",[2]) and sand treaders. Those occurring in New Zealand, Australia, and Tasmania are typically referred to as jumping or cave wētā.[3] Most are found in forest environments or within caves, animal burrows, cellars, under stones, or in wood or similar environments.[4] All species are flightless and nocturnal, usually with long antennae and legs.[3] More than 1100 species of Rhaphidophoridae are described.[1]
The well-known field crickets are from a different superfamily (Grylloidea) and only look vaguely similar, while members of the family Tettigoniidae may look superficially similar in body form.
Most cave crickets have very large hind legs with "drumstick-shaped" femora and equally long, thin tibiae, and long, slender antennae. The antennae arise closely and next to each other on the head. They are brownish in color and rather humpbacked in appearance, always wingless, and up to 5 cm (2.0 in) long in body and 10 cm (3.9 in) for the legs. The bodies of early instars may appear translucent.
As their name suggests, cave crickets are commonly found in caves or old mines. However, species are also known to inhabit other cool, damp environments such as rotten logs, stumps and hollow trees, and under damp leaves, stones, boards, and logs.[4][5] Occasionally, they prove to be a nuisance in the basements of homes in suburban areas, drains, sewers, wells, and firewood stacks. One has become a tramp species from Asia and is now found in hothouses in Europe and North America. Some reach into alpine areas and live close to permanent ice, such as the Mount Cook "flea" (Pharmacus montanus) and its relatives in New Zealand.[6]
An as-yet-unnamed genus was discovered within a cave in Grand Canyon–Parashant National Monument, on the Utah/Arizona border, in 2005. Its most distinctive characteristic is that it has functional grasping cerci on its posterior.[7]
Their distinctive limbs and antennae serve a double purpose. Typically living in a lightless environment, or active at night, they rely heavily on their sense of touch, which is limited by reach. While they have been known to take up residence in the basements of buildings,[8] many cave crickets live out their entire lives deep inside caves. In those habitats, they sometimes face long spans of time with insufficient access to nutrients. Given their limited vision, cave crickets often jump to avoid predation. Those species of Rhaphidophoridae that have been studied are primarily scavengers, eating plant, animal, and fungi material.[8] Although they look intimidating, they are completely harmless.[9][unreliable source?]
