Only two terminal abdominal filaments (cerci), filiform (string of beads) or forcep-like.
Long bead-like antennae.
Usually less than 5 mm long.
Found mostly in soil in damp environments.
About 1000 species worldwide, 300 European, and 11 British species.
Some authorities group this order with the Thysanura. It is thought that both the Collembola and the Protura may be descended from the Diplura. Most diplura are found in warmer or even tropical climates.
Diplura anatomy, reproduction and natural history
The diplura in the U. K. are usually less than 5 mm long. The young and adults look alike. They are pale coloured and feed on decaying plant material and fungal hyphae. Their antennae tend to be more robust than those of the Thysanura. As in the Collembola moulting can occur even after sexual maturity is reached.
There is just one family in the U. K., the Campodeidae (see left), of which there are 12 species. They are up to 1 cm long, and colourless.
Reproduction. The males place spermatophores at the end of a stalk on surfaces where the females are likely to find them. Once found by the female the sperm is used to fertilize her eggs. The eggs are smooth, spherical, and laid during summer in batches of 1 - 9. Any uncollected spermatophores are usually eaten by the male. In some species the females guard their eggs.
Diplura are fast moving. They are usually found under bark on dead trees, in tree stumps, under stones, and in leaf litter. Some species appear to live in colonies, but not enough is known about this to describe them as social.