Dictyoptera (parent)

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Dictyoptera
Macropanesthia rhinoceros, a burrowing cockroach from the Blaberidae family

Macropanesthia rhinoceros , a burrowing cockroach from the Blaberidae family

Systematics
Sub-stem : Six-footed (Hexapoda)
Class : Insects (Insecta)
Flying insects (Pterygota)
New winged wing (Neoptera)
Polyneoptera
Superordinate : Dictyoptera
Scientific name
Dictyoptera
Leach , 1818
Orders

The Dictyoptera are a superiority of the insects, in which the scraping , with about 4600 species, termites , with about 3000 species, and the Mantis , are combined with about 2300 species.

features

At first glance, the orders summarized here have different shapes and different ways of life. The following common features are rated as morphological autapomorphies :

  • The eggs are placed in an oothec , which is then enveloped by a later hardening secretion from accessory glands located in the ninth segment of the abdomen. This feature is secondary in the termites, but is still preserved in one species ( Mastotermes darwiniensis ). In connection with this: regression of the ovipositor , which is only rudimentary or has been completely lost.
  • The tentorium , a sclerite inside the head, is perforated in the middle, the connective of the abdominal cord runs through the hole .
  • In females, a subgenital plate is formed, which is formed from the coxosternum (a sclerite) of the seventh abdominal segment.
  • The proventriculus, a section of the digestive system, has a more or less six-fold (hexaradial) symmetry. In most basal insect orders, it is bilaterally symmetrical. It serves as a muscular chewing stomach that is toothed on the inside.
  • The external genital appendages of the males are similar in structure, they are always clearly asymmetrical. They are in different groups, apparently secondary, reversed in mirror symmetry. However, the genital appendages of the termites (apart from rudiments in a few species) are completely regressed.

Phylogenetic position

External system

The association of the three classical orders to the Dictyoptera is supported by numerous scientific studies and is considered to be well secured; it has been adopted in all recent textbooks and textbooks.

The Dictyoptera belong to a group of hemimetabolic insect orders, which in many respects have similar morphological shape, the Polyneoptera . It is scientifically controversial whether the orders summarized here form a clade (a holophyletic community of descent), or whether the similarity only reflects a common level of organization and there is no closer relationship to one another; Many scientists today prefer a common ancestry, their sister group would then be the common clade from the Paraneoptera and the Holometabola . The relationships within the Polyneoptera are among the most difficult problems in insect phylogeny and are very controversial, neither analyzes on a morphological basis nor phylogenomic studies (construction of family trees based on the comparison of homologous DNA sequences) have so far been able to clarify the situation with certainty.

One hypothesis sees the small order of the ground lice (Zoraptera) as a possible sister group. This was proposed on the basis of genetic data and is supported by a special structure of the rDNA . But this is by no means undisputed, there are numerous contradicting studies

Empusa pennata , a fishing insect

Internal system

Although the position of the taxa within the Dictyoptera has long been disputed, more recent studies seem to indicate a consensus. The following results were achieved:

  • Virtually all studies indicate that cockroaches are paraphyletic to termites ; That means: The termites are more closely related to some groups of cockroaches than they are to each other. The cockroaches are therefore not a monophyletic group and must be resolved as a taxon according to the rules of cladistics . The most likely sister group within the cockroaches is the genus Cryptocercus , which shares the social way of life within dead wood with the termites . The termites are monophyletic.
  • The terrors are sister groups of the common clade of termites and cockroaches (this was postulated by Hennig as early as 1981, he called the common clade "Oothecaria" instead of Dictyoptera). These two groups are monophyletic.

The relationships within the (remaining) cockroaches are far less clear. Sister group of termites and Cryptocercidae together could, according to morphological data, be a clade from the family Lamproblattidae and the subfamily Corydiinae ( syn. Polyphaginae). According to molecular studies, the termites and Cryptocercidae are more closely related to the Blattidae . The currently accepted system of cockroaches follows this model, after which the termites, the Cryptocercidae and the superfamily Blattoidea (with the families Blattidae, Lamproblattidae and Tryonicidae ) form a clade.

Naming and rank

The name Dictyoptera is made up of the Greek roots dictyon ("net") and pteron ("wing") and should literally be translated as "net wing". However, the term Netzflügler in German is usually used for the order Neuroptera, so that the direct translation would be misleading and should be avoided.

The name Dictyoptera (as "Dictuoptera") was first introduced in 1818 by William Elford Leach in his treatment of the insect systematics in the Edinburgh Encyclopedia by Sir David Brewster . Nikita Kluge points out that the name for this taxonomic group is completely wrong, because Leach mentions the common cockroach as the only belonging species , i.e. does not include termites or catching horrors (he places termites in the Neuroptera, the catching horrors in the grasshoppers). Although this is unequivocally the case, this is how the name became common. Since no nomenclature rules apply to higher taxa in zoology (above the family level) , the names are assigned according to the consensus of the scientists, so that neither rules of priority according to other rules have to be observed.

Since, according to the results presented here, the earlier order of the cockroaches is paraphyletic, it must actually be resolved as a taxon according to the cladistic rules. In addition, the termites, as a sub-taxon of the cockroaches, are no longer equal to them and are viewed more as a superfamily than an order. For these reasons, numerous entomologists have started to view the Dictyoptera not as a superordinate but as an order.

Individual evidence

  1. ↑ a b c Klaus-Dieter Klass (2003): Relationships among the principal lineages of Dictyoptera inferred from morphological data. Entomological Treatises 61 (2): 134-137.
  2. ↑ Klaus-Dieter Klass & Rudolf Meier (2006): A phylogenetica Analysis of Dictyoptera (Insecta) based on morphological characters. Entomological Treatises 63 (1-2): 3-50.
  3. ↑ WCWheeler, M.Whiting, QDWheeler, JMCarpenter (2001): The phylogeny of the extant hexapod orders. Cladistics 17: 113-169. doi : 10.1111 / j.1096-0031.2001.tb00115.x
  4. ↑ Yanhui Wang, Michael S. Engel, Jose A. Rafael, Kai Dang, Haoyang Wu, Ying Wang, Qiang Xie, Wenjun Bu (2013): A Unique Box in 28S rRNA Is Shared by the Enigmatic Insect Order Zoraptera and Dictyoptera. PLoS ONE 8 (1): e53679. doi : 10.1371 / journal.pone.0053679
  5. ^ Y. Mashimo, Y. Matsumura, R. Machida, R. Dallai, M. Gottardo, K. Yoshizawa, F. Friedrich, B. Wipfler, RG Beutel (2014): 100 years Zoraptera — a phantom in insect evolution and the history of its investigation. Insect Systematics & Evolution 45 (4): 371 - 393. doi : 10.1163 / 1876312X-45012110
  6. ↑ a b cf. BRB Davis, SL Baldauf, PJ Mayhew (2009): Eusociality and the success of the termites: insights from a supertree of dictyopteran families. Journal of Evolutionary Biology 22: 1750-1761. doi : 10.1111 / j.1420-9101.2009.01789.x
  7. ↑ a b cf. Daegan Inward, George Beccaloni, Paul Eggleton (2007): Death of an order: a comprehensive molecular phylogenetic study confirms that termites are eusocial cockroaches. Biology Letters (2007) 3: 331-335. doi : 10.1098 / rsbl.2007.0102
  8. ^ George William Beccaloni: Blattodea Species File Online . Version 1.0 / 4.0. World Wide Web electronic publication. [1] (accessed on July 20, 2015)
  9. ^ George William Beccaloni & Paul Eggleton: Order Blattodea. In: Z.-Q. Zhang (Editor): Animal Biodiversity: An Outline of Higher-level Classification and Survey of Taxonomic Richness (Addenda 2013). Zootaxa 3148: 199-200.
  10. ^ WE Leach (1815): Classification. In: D. Brewster, Edinburgh Encyclopedia, vol. 9, Entomology: 67-162. scan of the original edition at archive.org
  11. ↑ Nikita Julievich Kluge (2010): Circumscriptional names of higher taxa in Hexapoda. Bionomina 1: 15-55.