Archaeognatha
Archaeognatha Temporal range:
| |
---|---|
Rock bristletail | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Subclass: | Monocondylia Haeckel, 1866 |
Order: | Archaeognatha Börner, 1904 |
Families[2] | |
| |
Synonyms | |
|
The Archaeognatha are an
Until the late 20th century the suborders
The order Archaeognatha is cosmopolitan; it includes roughly 500 species in two families.[6] No species is currently evaluated as being at conservation risk.[7]
Description
Archaeognatha are small insects with elongated bodies and backs that are arched, especially over the
: 341–343Unlike other insect orders, they do not have olfactory receptor-coreceptors (Orco), which have either been lost or were never present in the first place.[10][11]
Archaeognatha differ from Zygentoma in various ways, such as their relatively small head, their bodies being compressed laterally (from side to side) instead of flattened dorsiventrally, and in their being able to use their tails to spring up to 30 cm (12 in) into the air if disturbed. They have eight pairs of short appendages called styli on abdominal segments 2 to 9. Family Machilidae is also unique among insects in possessing small muscleless styli on the second and third thoracic legs,[12] but are absent on the second pair of thoracic legs in some genera.[13] Similar stylets on the legs are absent in family Meinertellidae.[14] They have one or two pairs of eversible membranous vesicles on the underside of abdominal segments 1 to 7, which are used to absorb water and assisting with molting.[15] There are nine pairs of spiracles; two pairs on the thorax, and seven pairs on abdominal segments 2 to 8.[16] The pair of spiracles on the first abdominal segment has been lost.[17]
Further unusual features are that the abdominal sternites are each composed of three sclerites, and they cement themselves to the substrate before molting, often using their own feces as glue.[18] The body is covered with readily detached scales, that make the animals difficult to grip and also may protect the exoskeleton from abrasion. The thin exoskeleton offers little protection against dehydration, and they accordingly must remain in moist air, such as in cool, damp situations under stones or bark.
Etymology
The name Archaeognatha is derived from the
An alternative name, Microcoryphia,[4] comes from the Greek μικρός, mikros, 'small', and κορυφή, koryphē, which in context means 'head'.[20]
Taxonomy
Families | No. of Species | Defining Notes | Image |
---|---|---|---|
Machilidae | 250 | Most are restricted to rocky shorelines | Need specific image |
Meinertellidae | 170[21] | Lack scales at base of hind legs and antennae | Need specific image |
Biology
Archaeognatha occur in a wide range of habitats. While most species live in moist soil, others have adapted to chaparral, and even sandy deserts. They feed primarily on algae, but also lichens, mosses, or decaying organic detritus.
Three types of mating behavior are known. In some species the male spins a silk thread (carrier thread) stretched out on the ground. On the thread there are droplets of sperm which the female will take up when her ovipositor makes contact. In others a packet of sperm (spermatophore) is deposited on the top of a short stalk. If a female takes up the sperm or not is often random, but in many species the male will try to lead the female's genitals over the sperm during courtship. A more direct way of fertilization occurs in species of the genus Petrobius, where the male place a droplet of sperm directly on the female's ovipositor. [22][23] One hypothesis is that the external genitals of insects started as structures specialized for water-uptake, which could reach deeper crevices than the coxal vesicles, and over time the female would use it to take up sperm from the ground instead of water.[24] After fertilization she lays a batch of around 30 eggs in a suitable crevice. The young resemble the adults, and take up to two years to reach sexual maturity, depending on the species and conditions such as temperature and available food.
Unlike most insects, the adults continue to moult after reaching adulthood, and typically mate once at each instar. Archaeognaths may have a total lifespan of up to four years, longer than most larger insects.[1]
References
- ^ ISBN 0-19-510033-6.
- The Paleobiology Database. Retrieved 26 November 2020.
- S2CID 86430759.
- ^ ISBN 978-0-12-404692-4.
- ^ A. Blanke, M. Koch, B. Wipfler, F. Wilde, B. Misof (2014) Head morphology of Tricholepidion gertschi indicates monophyletic Zygentoma. Frontiers in Zoology 11:16 doi:10.1186/1742-9994-11-16
- ISBN 9781444344967.
- ^ NC State University, ENT 425 | General Entomology | Resource Library | Compendium [Archeognatha]
- ISBN 9781461569183.
- ISBN 9780080920900.
- PMID 33502604.
- PMID 30063003.
- ISBN 9781501717918.
- ^ Mendes, Luís F. (1990). "An Annotated List of Generic and Specific Names of Machilidae (Microcoryphia, Insecta) with Identification Keys for the Genera and Geographical Notes".
- JSTOR 25010224.
- ISBN 978-0-19-265483-0.
- ISBN 9789401705080.
- ^ Proceedings of the 1st Dresden Meeting on Insect Phylogeny: "Phylogenetic Relationships within the Insect Orders". (Dresden, September 19-21, 2003)
- ISBN 9781477310359.
- S2CID 85309726.
- ^ H. G. Liddell (1889). An Intermediate Greek-English Lexicon: Based on the 7th Ed of Liddell & Scott's Lexicon.
- .
- PMID 23578395.
- PMID 22766521.
- ^ 9th Dresden Meeting on Insect Phylogeny 2019
External links
- Archaeognatha - Tree of Life Web Project
- Microcoryphia Virginia Polytechnic Institute and State College Department of Entomology[dead link]