Embioptera
Small insects that spin silk galleries and live subsocially.
Embioptera, called webspinners or footspinners, is a small order of mostly tropical and subtropical insects within the subclass Pterygota. They have also been known as Embiodea or Embiidina. Over 400 species across 11 families have been described, and the oldest known fossils come from the mid-Jurassic. The insects look very similar: long, flexible bodies, short legs, and only males have wings.
Webspinners live gregariously in subsocial colonies, spinning fine silk from glands on their front legs to build galleries. These colonies usually consist of related females and their offspring. Adult males do not feed and die shortly after mating. In some species, males have wings and can disperse, while females stay near where they hatched. A newly mated female may leave the colony to start a new one nearby, or emerge to find a new food source so the galleries can be extended, but generally these insects rarely leave their silk tunnels.
The name Embioptera means "lively wings," from Greek words for "lively" and "wing." This name is not considered very descriptive for their flying ability; it may instead refer to how quickly they move forward and backward. The common name "webspinner" comes from the unique tarsi on their front legs, which produce multiple silk strands used to build web-like galleries.
Early entomologists grouped webspinners with termites or neuropterans, suggesting names like Adenopoda, Embidaria, Embiaria, and Aetioptera. In 1909, Günther Enderlein used Embiidina, which was widely adopted for a time. Edward S. Ross proposed Embiomorpha in 2007. The currently most accepted ordinal name, Embioptera, was suggested by Arthur Shipley in 1904.
Fossils of webspinners are rare. The group likely first appeared in the Jurassic; the oldest known are *Sinembia rossi* and *Juraembia ningchengensis*, both placed in the new family Sinembiidae, from the Middle Jurassic of Inner Mongolia, described in 2009. The female of *J. ningchengensis* had wings, supporting Ross’s idea that both sexes of ancestral webspinners were winged. Species such as *Atmetoclothoda orthotenes*, possibly the first fossil member of the "primitive" family Clothodidae, have been found in mid-Cretaceous amber from northern Myanmar. *Litoclostes delicatus* (Oligotomidae) comes from the same site. The most fossils come from mid-Eocene Baltic amber and early-Miocene Dominican amber.
Quick Facts
- Taxon
- Embioptera
Facts from the source article.
Lore & Background
Webspinners have a remarkably uniform body form: long, flexible, cylindrical, with short legs and kidney-shaped compound eyes. Only males possess wings, which are long and narrow with simple venation; these wings are stiffened for flight by hemolymph-filled sinus veins and can fold forward to avoid snagging in silk tunnels. The front tarsi contain the silk-producing glands, and the hind femora are enlarged to house muscles for rapid backward movement. The abdomen ends in two-segmented cerci that are sensitive to touch, allowing navigation while moving backward through narrow galleries.
These insects are gregarious, living in colonies of related females and their offspring. Adult males do not feed and die soon after mating; some males are winged and can disperse, while females remain near their hatching site. Newly mated females may leave to establish a new colony nearby, and individuals rarely venture from their silk galleries except to find new food sources. The eggs hatch into nymphs that undergo incomplete metamorphosis, moulting four times before adulthood.
Reader's Guide
The order Embioptera represents a unique evolutionary specialization for a silk-based, subsocial lifestyle within the Polyneoptera. Their phylogenetic position has been debated; a 2012 analysis combining morphological and molecular evidence placed them within the Polyneoptera, but the exact relationships remain unresolved. Internally, four families (Clothodidae, Anisembiidae, Oligotomidae, and Teratembiidae) are robustly monophyletic, while others like Embiidae, Scelembiidae, and Australembiidae show uncertain status. The group likely first appeared in the Jurassic, with fossils rare but known from mid-Cretaceous amber and Eocene/Oligocene deposits. Their distinctive silk-spinning apparatus and ability to move equally well forward and backward in tight tunnels are key adaptations. The name Embioptera, meaning 'lively wings,' was proposed in 1904, though earlier names such as Embiidina and Embiomorpha have also been used. The common name 'webspinner' derives from the silk produced by the front tarsi.
Did You Know?
- Webspinners produce silk from glands on the enlarged basal tarsomere of their front legs.
- Only male webspinners have wings; females and nymphs are wingless.
- The oldest known webspinner fossils, Sinembia rossi and Juraembia ningchengensis, are from the Middle Jurassic of Inner Mongolia.
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