The order Diplura ("two-pronged bristletails") is one of three orders of non-insect hexapods within the class Entognatha (alongside Collembola (springtails) and Protura). The name "diplura", or "double tail", refers to the characteristic pair of caudal appendages or filaments at the terminal end of the body.
Around 800 species of diplurans have been described.
Anatomy
left|thumb|280x280px|A dipluran of the family Campodeidae
Diplurans are typically long, with most falling between . However, some species of Japyx may reach . They have no eyes and, apart from the darkened cerci in some species, they are unpigmented. The abdomens of diplurans bear eversible vesicles, which seem to absorb moisture from the environment and help with the animal's water balance.
Diplurans possess a characteristic pair of cerci projecting backwards from the last of the 11 abdominal somites. These cerci may be long and filamentous or short and pincer-like, leading to occasional confusion with earwigs. Some diplurans have the ability to shed their cerci if necessary (autotomy). Moulting occurs up to 30 times throughout the life of a dipluran, which is estimated to last up to one year.
As entognaths, the mouthparts are concealed within a small pouch by the lateral margins of the head capsule. The mandibles usually have several apical teeth. but are rarely seen because of their size and subterranean lifestyles.
Reproduction
Like other non-insect hexapods, diplurans practice external fertilisation. Males lay up to 200 spermatophores a week, which are held off the ground by short stalks and probably only remain viable for about two days.
- Campodeidae: possess elongate, flexible cerci that may be as long as the antennae and have many segments. Feed on soil fungi, mites, springtails, and other small soil invertebrates, as well as detritus. The fossil record of the Diplura is sparse, but one apparent dipluran dates from the Carboniferous.