Webspinner Fossil range: 199–0 Ma PreЄ Є O S D C P T J K Pg N Jurassic - Recent
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Subclass:	Pterygota
Infraclass:	Neoptera
Order:	Embioptera Lameere, 1900
Families
There are 2 suborders and 10 families: Andesembiidae Anisembiidae Australembiidae Clothodidae Embiidae Embonychidae Notoligotomidae Oligotomidae Teratembiidae Sorellembiidae

Webspinners or embiids (order Embioptera) are a small group of mostly tropical and subtropical insects, classified under the subclass Pterygota. The order has also been referred to as Embiodea or Embiidina^[1] The name Embioptera (lively wings) comes from Greek, embio meaning lively and ptera meaning wings, and refers to the fluttery movement of wings that was observed in the first male specimen described.

The group probably first appeared during the Jurassic and is well represented in Cretaceous amber. All the females are wingless, and in some species also the males. Webspinners spin silk from structures on their front legs. They use the silk to make a weblike pouch or gallery in which they live. The galleries may be found in leaf litter, under rocks, or under bark.

The order contains only some 300 species, most of which are found only in tropical climates, although a small number of temperate species do exist.

[edit] Description

All webspinners have a remarkably similar body form, although they do vary in colouration and size. The head has projecting mouthparts with chewing mandibles. The compound eyes are kidney-shaped, there are no ocelli, and the antennae are long, with up to 32 segments.^[2]

The body is cylindrical in form, adapted for the tubular galleries within which the insects live. The first segment of the thorax is small and narrow, while the second and third are larger and broader, especially in the males, where they include the flight muscles. The wings, where present, are long and narrow, with relatively simple venation. The legs are short and sturdy, with an enlarged tarsomere on the first pair, containing the silk-producing glands. The abdomen has ten segments, with a pair of cerci on the final segment. These cerci are highly sensitive to touch, and allow the animal to navigate while moving backwards through the gallery tunnels, which are too narrow to allow the insect to turn round.^[2]

The female lays her eggs within the gallery, where they hatch into nymphs that resemble small, wingless adults. After a brief period of parental care, the nymphs moult a total of four times before reaching adulthood. Adult males never eat, and leave the home colony almost immediately to find a female and mate. In some species, the female then eats the male, but in any event, the male will not survive for long after mating. A few species are known to be parthenogenetic.^[2]

The nymphs and adult females are herbivorous, feeding on leaf litter, moss, bark and lichen.

[edit] Galleries

Webspinners continually extend their galleries into new food-sources, and expand their existing galleries as they grow in size. The insects spin silk by moving their forelegs back and forth over the substrate, and rotating their bodies to create a cylindrical, silk-lined tunnel. Older galleries have multiple laminate layers of silk. Each gallery complex contains a number of individuals, often descended from a single female, and forms a complex maze-like structure, extending from a secure retreat into whatever vegetable food matter is available nearby. The size and complexity of the colony varies between species, and they can be very extensive in those species that live in hot and humid climates.^[2]

[edit] References

• Grimaldi, D. and Engel, M.S. (2005). Evolution of the Insects. Cambridge University Press. ISBN 0-521-82149-5. 

World list of extant and fossil Embiidina (California Academy of Sciences)

Wikispecies has information related to: Embiidina

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