Order EMBIOPTERA
Web-spinners
Compiler and date details
31 Dec 1997 - Gerasimos Cassis, Australian Museum, Sydney, New South Wales, Australia
Introduction
The Embioptera (Embiidina) or web-spinners is a small order of exopterygote neopteran insects (Kristensen 1991). The relationships of this highly autapomorphic group are obscure but they share similarities with the Plecoptera, Dermaptera and Zoraptera (Davis 1944). Ross (1982) indicated that Embioptera are most closely related to Plecoptera, Isoptera and Phasmatodea. Kukalová-Peck (1991) indicated that embiids have orthopteroid wing venation.
The group is cosmopolitan, predominantly tropical but found also in warm temperate regions. They are most diverse in the Ethiopian, Neotropical and Oriental regions. Ross (1982) reported that 200 embiopteran species were named but estimated that possibly 2000 species exist.
Embioptera are mandibulate with a strongly prognathous head. They always have a sclerotised gula. The antennae are filiform and contain up to 32 segments. The eyes are always present, but reduced in females and apterous males. Ocelli are absent. The females are always apterous whereas the males are macropterous, brachypterous or apterous. The legs are short, characterised by three-segmented tarsi, with the basal segment of the foretarsi greatly swollen, containing silk glands. The abdomen has ten segments and the cerci have two segments (Ross 1991).
Embiids are herbivorous and feed on outer bark of trees, dead leaves, moss and lichens. They are most noted for the formation of silk galleries which they inhabit. The galleries are sometimes exposed on rocks and bark, or hidden in crevices. The galleries of other species are found in leaf litter, on old fence posts or among hanging moss (Ross 1991).
The suprageneric classification of the Embioptera was reviewed by Ross (1970). He divided the order into three suborders and recognised 14 families. Unfortunately, he did not provide names for his two new suborders and six of his families. Subsequently, Ross (1982, 1991) did not subdivide the embiids into suborders, listing only eight families: Anisembiidae, Australembiidae, Clothodidae, Embiidae, Embonychidae, Notoligotomidae, Oligotomidae and Teratembiidae. This classification is followed here.
The Australian fauna comprises three families (Australembiidae, Notoligotomidae and Oligotomidae), five genera and 26 described species, six with subspecies. Ross (1991) lists 65 Australian species but only 26 species and 20 subspecies have been described.
Acknowledgements
The illustrations used in the published work family introductions, except for Oligotomidae, are from Ross (1991). They are reproduced with permission from CSIRO Entomology and the Melbourne University Press. The modified oligotomid illustration is taken from Insects of Hawaii, with approval from Ross and Zimmerman. Compilation of this section of the Zoological Catalogue of Australia database was funded by the Australian Biological Resources Study.
Database Notes
The information on the Australian Faunal Directory site for the Embioptera is derived from the Zoological Catalogue of Australia database compiled on the Platypus software program. It incorporates changes made to the work published on 2 September 1998 as (Cassis, G., 1998)
Limital Area
Distribution data in the Directory is by political and geographic region descriptors and serves as a guide to the distribution of a taxon. For details of a taxon's distribution, the reader should consult the cited references (if any) at genus and species levels.
Australia is defined as including Lord Howe Is., Norfolk Is., Cocos (Keeling) Ils, Christmas Is., Ashmore and Cartier Ils, Macquarie Is., Australian Antarctic Territory, Heard and McDonald Ils, and the waters associated with these land areas of Australian political responsibility. Political areas include the adjacent waters.
Terrestrial geographical terms are based on the drainage systems of continental Australia, while marine terms are self explanatory except as follows: the boundary between the coastal and oceanic zones is the 200 m contour; the Arafura Sea extends from Cape York to 124 DEG E; and the boundary between the Tasman and Coral Seas is considered to be the latitude of Fraser Island, also regarded as the southern terminus of the Great Barrier Reef.
Distribution records, if any, outside of these areas are listed as extralimital. The distribution descriptors for each species are collated to genus level. Users are advised that extralimital distribution for some taxa may not be complete.
References
Cassis, G. 1998. Embioptera. pp. 377–392 in Houson, W.W.K. & Wells, A. (eds). Zoological Catalogue of Australia. Vol. 23. Archaeognatha, Zygentoma, Blattodea, Isoptera, Mantodea, Dermaptera, Phasmatodea, Embioptera, Zoraptera. Melbourne : CSIRO Publishing, Australia xiii pp. 464
Davis, C. 1944. Studies in Australian Embioptera. Part VII: New Embioptera from tropical Australia. Proceedings of the Linnean Society of New South Wales 69: 16–20
Kristensen, N.P. 1991. Phylogeny of extant hexapods. pp. 125–140 in CSIRO (ed.) The Insects of Australia. A textbook for students and research workers. Melbourne : Melbourne University Press Vol. 1 2nd Edn
Kukalová-Peck, J. 1991. Fossil history and the evolution of hexapod structures. pp. 141–179 in CSIRO (ed.) The Insects of Australia. A textbook for students and research workers. Melbourne : Melbourne University Press Vol. 1 2nd Edn
Ross, E.S. 1970. Biosystematics of the Embioptera. Annual Review of Entomology 15: 157–172
Ross, E.S. 1982. Embiidina. pp. 387–389 in Parker, S.P. (ed.) Synopsis and Classification of Living Organisms. New York : McGraw Hill Book Co
Ross, E.S. 1991. Embioptera. Embiidina (Embiids, web-spinners, foot-spinners). pp. 405–409 in CSIRO (ed.) The Insects of Australia. A textbook for students and research workers. Melbourne : Melbourne University Press Vol. 1 2nd Edn