Earth bugs

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Earth bugs
Tritomegas sexmaculatus

Tritomegas sexmaculatus

Systematics
Class : Insects (Insecta)
Order : Schnabelkerfe (Hemiptera)
Subordination : Bed bugs (heteroptera)
Partial order : Pentatomomorpha
Superfamily : Pentatomoidea
Family : Earth bugs
Scientific name
Cydnidae
Billberg , 1820

Earth bugs (Cydnidae) are a family of bugs (Heteroptera) within the suborder Pentatomomorpha . About 560 species of about 110 genera are known of them. In Europe 63 species are represented, 19 of which occur in Central Europe. The animals owe their German name to their way of life. Many species live in the ground and are physically well adapted to the burrowing way of life. In the course of the history of their research, the composition and taxonomic position of the family has been the subject of intense and controversial discussions and even today these have not been fully clarified.

features

The bugs become 2 to 20 millimeters long. Most species have an egg-shaped, curved, heavily sclerotized body that is black or brown in color and has a smooth, shiny surface. Many species have legs that are modified for digging.

The head is often wide and flattened and is square or semicircular in shape. Both it and the pronotum have thorns in many species; these are transformed setae that serve as mechanical sense organs. The antennae are five-part. The hips ( coxes ) have distally flattened setae or bristles that rest on the surface of the thigh rings ( trochanters ). The rails ( tibia ) are provided with numerous long thorns. The tripartite tarsi are often delicate and severely receded. Trichobothria are formed on the third to seventh sternum on the abdomen , which are usually transverse or longitudinal at the level of the spiracles . Unlike the other segments, the spiracles on the second abdominal segment are located on a membranous area on the side of the anterior part of the sternum. In the females, the eighth laterotergites are fused. The spermatheca of males is small and has two flanges.

The nymphs have their scent gland openings on the abdomen between the third to sixth tergum . In a number of species, the nymphs on the abdomen are red or yellowish-white in color.

Although the earth bugs are a relatively primitive group of the Pentatomoidea, many species have physical adaptations to life in the ground. These include the flattened, thorny head, the widened, flattened and heavily thorny front legs, the smooth body surface and, in some species, the strongly thickened, strong, thorny thighs ( femora ) of the hind legs. In many individuals you can see signs of wear and tear on the legs, especially on the tapering front rails, which probably result from digging. The comb-like setae distal on the hips are probably used to prevent dust or the like from entering the joint between the hip and the thigh ring during the dig. Assuming this assumption is correct, it would mean that digging is a primordial trait, as all species in the family, including those that do not dig, have these setae. A stridulation organ is developed in many species . The noises are generated by the postcubital vein on the hemielytres and a tergum on the abdomen. This is probably a plesiomorphic feature of the Pentatomoidea.

Occurrence

The family is distributed worldwide and has its main distribution areas both in the tropics and in the temperate latitudes.

Way of life

The way of life of the earth bugs is insufficiently researched. Many species live in the ground and the adults are often found in the ground around plant roots where they suckle ( Cydninae ). The females lay their eggs on the ground, the nymphs also live in the ground. Members of the family were found to a depth of about 1.5 meters below the surface. From Scaptocoris castaneus is documented that they with their scythe-shaped front rails scraping the ground in front of him and pushes with the other leg behind and compressed again, so will be no real transition, but the animals quasi move only in a small chamber. Little is known about most of the species of the Amnestinae , but they seem to be less tied to an earth-dwelling way of life, since representatives were found several times when shearing off vegetation and under parts of plants and stones. Both nymphs and adults of Amnestus subferrugineus were found in Panama in the guano of bat caves , which is why it is assumed that they feed on seeds found in them. The representatives of the subfamily Sehirinae live on top of plants. In North America and Europe, it is found mainly on mint family (Lamiaceae), predatory leaf family (Boraginaceae) and related plants. The black and white earth bug ( Tritomegas bicolor ) is known to lay its eggs in clutches of more than 100 in chambers just below the surface of the earth and that the female defends them after they have been laid. The females also take care of their brood with the young nymphs, who gather around their mother. Defense includes passive sitting on the clutch, targeted shielding from predators and also reacting to unfavorable environmental conditions, during which the female transports the eggs to a more suitable location. In some species, the females also transmit endosymbionts to their offspring.

Many species can fly well. The animals like to fly at night, sometimes in large numbers to artificial light sources, which means that the individual species have been relatively well researched taxonomically. Sometimes the flight times of the respective species are very short and for some species they are limited to certain times of the day (e.g. the first hour after sunset). With the help of their stridulation organs, most earth bugs can also produce chirps during mating. The males can be heard chanting advertisements and rivals, the females respond to the males singing. The noises transmit vibrations to the substrate or the ground, which the bugs with receptors in their legs can perceive. Noises are also generated when the animals are disturbed.

More than two dozen species are considered pests in agriculture. More important agricultural pests include Scaptocoris castanea on the roots of a large number of cultivated plants in Brazil, Stibaropus indonesicus on the roots of sugar cane in Indonesia, Atarsocoris brachiariae on the roots of pasture grasses in Brazil, Byrsinus varians on pearl millet in India, Microporus nigrita on the roots of crops on sandy soils in Europe, Panagaeus bilineatus on crops, especially peanuts, in the USA.

gallery

Taxonomy and systematics

The earth bugs (Cydnidae) are probably the taxon of the Pentatomoidea that has been discussed most controversially in the course of the history of their research. The family was first described by Gustaf Johan Billberg in 1820 . Amyot & Serville first divided the group into two subfamilies (Cydninae and Sehirinae) in 1843. Froeschner recognized five subfamilies in 1960 and Dolling in 1981 eight. The latter included the Thyreocorinae and the Thaumastellidae, which had been considered a family within the Lygaeoidea until then , as subfamilies. Lis divided the family in his work from 1994 to 2001 into seven subfamilies, where he set up a new subfamily, the Cephalocteinae with the two tribe Cephalocteini and Scaptocorini (previously separate subfamily). Schuh & Slater (1995) considered the Thyreocorinae and those of Schaefer et al. In 1988 Parastrachiinae were added as subfamilies of the earth bugs, but saw the Thaumastellidae following Jacobs (1989) as an independent family. Other authors suggested different classifications. An investigation based on morphological features and DNA sequences from 2008 by Grazia et al. confirmed Dolling's (1981) point of view on the basis of the morphological characteristics, but could not confirm it in the other analyzes. However, there was also no clear alternative, whereby, due to insufficient DNA material of some of the subfamilies in question, it was noted during the investigation that the monophyly of the Cydnidae sensu Dolling should be questioned, but that more detailed investigations were necessary.

As a result, Grazia et al. a preliminary consideration of the Thaumastellidae and the Corimelaenidae (including Parastrachiinae as a subfamily and the genera of the former Thyreocorinae) as independent families within the Pentatomoidea, as these would be primarily responsible for the paraphyly of the Cydnidae sensu Dolling. Accordingly, the Cydnidae would, taking Lis, corrected by Grazia et al. consist of the following remaining subfamilies and tribe:

Species in Europe

The following species occur in Europe:

More types

A selection of non-European species:

Fossil evidence

The oldest fossil Cydnidae come from the older Cretaceous , due to uncertainties in dating possibly from the younger Jurassic . They are assigned to the subfamily Amnestinae. Another fossil species, possibly also an Amnestinae, comes from the also Cretaceous Santana Formation of Brazil

Earth bugs have been identified in Dominican amber . The age of this amber is between 25 and 40 million years (Lower Miocene to Eocene ). The conservation of soil-dwelling organisms in amber is unusual and probably goes back to the very strong resin flow of the "Dominican amber tree", so that viscous resin lumps fell to the ground and living organisms were trapped there.

supporting documents

Individual evidence

  1. ↑ a b c d Jocelia Grazia, Randall T. Schuh, Ward C. Wheeler: Phylogenetic relationships of family groups in Pentatomoidea based on morphology and DNA sequences (Insecta: Heteroptera) . In: Cladistics . tape 24 , no. 6 , December 1, 2008, p. 932-976 , doi : 10.1111 / j.1096-0031.2008.00224.x .
  2. ↑ a b c d e f g h Family Cydnidae. (No longer available online.) Australian Biological Resources Study. Australian Faunal Directory, archived from the original on April 16, 2014 ; Retrieved April 21, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.environment.gov.au
  3. ↑ a b c d e f g h i RT Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995, pp. 220ff.
  4. ↑ a b Cydnidae. Fauna Europaea, accessed April 21, 2014 .
  5. ↑ a b c d Ekkehard Wachmann , Albert Melber, Jürgen Deckert: Bugs. Volume 4: Pentatomomorpha II: Pentatomoidea: Cydnidae, Thyreocoridae, Plataspidae, Acanthosomatidae, Scutelleridae, Pentatomidae. (=  The animal world of Germany and the adjacent parts of the sea according to their characteristics and their way of life . 81st part). Goecke & Evers, Keltern 2008, ISBN 978-3-937783-36-9 , pp.  9 ff .
  6. ↑ Dominique Pluot-Sigwalt, Jerzy A. Lis: Nymphal and adult cephalic chaetotaxy of the Cydnidae (Hemiptera: Heteroptera), and its adaptive, taxonomic and phylogenetic significance . In: European Journal of Entomology . tape 99 , 2002, pp. 99-109 .
  7. ↑ Jerzy A. Lis, Miriam Becker, Carl W. Schaefer: Burrower Bugs (Cydnidae). In: Carl W. Schaefer, Antonio Ricardo Panizzi (Ed.): Heteroptera of Economic Importance. CRC Press, 2000, p. 405 ( limited preview in Google Book search).
  8. ↑ Jerzy A. Lis: Burrower bugs of the Old World - a catalog (Hemiptera: Heteroptera: Cydnidae) . In: Genus. International Journal of Invertebrate Taxonomy . tape 10 , no. 2 , 1999, p. 165–249 ( bishopmuseum.org [PDF; accessed June 21, 2014]).
  9. ↑ Jerzy A. Lis: Peltoxys pilosus n. Sp. from the Democratic Republic of Congo with a key to known species of the genus (Hemiptera: Heteroptera: Cydnidae: Garsauriinae) . In: Genus. International Journal of Invertebrate Taxonomy . tape 13 , no. 2 , 2002.
  10. ↑ Jerzy A. Lis: Taxonomy and phylogeny of Cephalocteinae with a reference to their historical biogeography (Hemiptera: Heteroptera: Cydnidae) . In: Polskie Pismo Entomologiczne . tape 68 , no. 2 , 1999, p. 111–131 ( researchgate.net [PDF; accessed June 21, 2014]).
  11. ↑ Yunzhi Yao, Wanzhi Cai, Dong Ren (2007): The first fossil Cydnidae (Hemiptera: Pentatomoidea) from the Late Mesozoic of China. Zootaxa 1388: 59-68.
  12. ^ David M. Martill, Günter Bechly, Robert F. Loveridge: The Crato Fossil Beds of Brazil Window into an Ancient World. Cambridge University Press, 2011 ISBN 978-0-521-30080-3 . Appendix: species list for the Crato Formation, p.594.
  13. ↑ David A. Grimaldi: Amber - Window to the Past. New York 1996. ISBN 0-8109-1966-4 .

literature

  • RT Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995.

Web links

Commons : Earth Bugs (Cydnidae)  - Collection of images, videos and audio files