Dicranocephalus

Dicranocephalus
	Dicranocephalus agilis
Systematics
Order :	Schnabelkerfe (Hemiptera)
Subordination :	Bed bugs (heteroptera)
Partial order :	Pentatomomorpha
Superfamily :	Coreoidea
Family :	Stenocephalidae
Genre :	Dicranocephalus
Scientific name of the family
	Stenocephalidae
	Dallas , 1852
Scientific name of the genus
	Dicranocephalus
	Hahn , 1826

Nymph of a Dicranocephalus species

Dicranocephalus is the only genus of the Stenocephalidae familywithin the bedbugs - suborder Pentatomomorpha . The bugs are sometimes referred to as "wolf milk bugs" in German. Some authors believe that the Stenocephalidae familyincludesanother genus, Psotilnus , and a total of 30 to 36 species. Moulet (1995) synonymized this genus with Dicranocephalus and reduced the number of species due to synonymy to 16. However, this approach is not undisputed and was not shared by Tshernova, who reversed the synonymizations in 1996. The discrepancy arises mainly when looking at Dicranocephalus agilis , which is either a species complex or a widespread, polymorphic species. 5 species occur in Europe , 3 of them in Central Europe.

features

The bugs are 8 to 15 millimeters long and have a relatively slender, elongated body with parallel side edges. They are brown to yellow in color and look very similar to edge bugs (Coreidae).

The head is elongated and roughly triangular. The point eyes ( ocelli ) are close to the trapezoidal pronotum . The buccules , the laterally delimiting the cheek plates, are short and flat, the mandibles extend beyond the frontal plate ( clypeus ). The antennae are four-part. The membranes of the hemielytres are opaque and have one large and one small basal cell, from which a number of longitudinal arteries arise. Scent gland openings are formed on the metathorax . The stigmata on the abdomen are all located anteriorly . Inner laterotergites are formed. Trichobothria are located laterally on the fifth and sixth sternum on the abdomen and are grouped in front of the spiracles. In the females, the seventh abdominal star is completely divided and their ovipositor is slashed (laciniat), whereby the third valvulae are missing. In the male, the spermatheca is sclerotized and has a spherical bulb apically. The nymphs have their scent gland openings on the abdomen between the fourth to sixth tergum .

The eggs are elongated and have four to nine micropylar processes grouped at the anterior pole.

distribution

The family has its main distribution center in the tropics and subtropics of the eastern hemisphere including Australia. Several species also occur in the temperate latitudes of the Palearctic . One species, Dicranocephalus insularis , was considered to be endemic to the Galapagos Islands , but despite a careful search it was no longer found and considered very rare or extinct. However, it is now suspected of having a kind of North African and South Asian distribution ( Dicranocephalus bianchii ) conspecific is (it is therefore concerns only one type) and actually later than the beginning of the 19th century has been introduced by humans in the Galapagos. D. bianchii should therefore be synonymous as a younger taxon.

Way of life

Little is known about the way the bedbugs live. They feed phytophag on higher plants. They are regularly nested by different types of milkweed family (Euphorbiaceae), especially the genus Wolf milk ( Euphorbia ), on which they reproduce. The females lay their eggs on the surface of the stem and not in the plant tissue, despite their laciniate ovipositor. However, there are also polyphagous species which, in addition to the milkweed family, also feed on a wide range of other plant species from the families of the barberry family (Berberidaceae), cypress family (Cupressaceae), pine family (Pinaceae) and rose family (Rosaceae). The European species overwinter under stones.

Taxonomy and systematics

Pierre André Latreille first recognized the group as family in 1825. This view was followed by other authors, such as William Sweetland Dallas 1852 or Douglas & Scott 1865. Carl Stål (1872) and, for example, Puton (1881), however, did not follow this view and regarded the group as a tribe of Stenocephalini of the curved sensor bugs (Alydidae). Finally, in 1957, when Scudder examined the relationship of the genus Dicranocephalus , he showed that the group deserves family status . All well-known authors to date have followed this view. The relationship of the family to other families of bugs has been controversial, as it has features of both the coreoid (in particular the external appearance of the nymphs, the shape of the male phallus and four-lobed primary salivary gland) and the lygaeoid (structure of the ovipositors, spermatheca and eggs ) having. In his revision of the Pentatomomorpha with a focus on the Lygaeoidea in 1997, Henry came to the conclusion that the family can be assigned to the superfamily Coreoidea due to the short buccules and the separate dorsal scent gland openings on the abdomen and that it is the sister group of the Hyocephalidae . He justifies this with the (supericorn) antennae that are deflected above the compound eyes and the mobility of the eighth paratergite.

The following species occur in Europe:

Dicranocephalus agilis ( Scopoli , 1763)
Dicranocephalus albipes ( Fabricius , 1781)
Dicranocephalus marginicollis ( Puton , 1881)
Dicranocephalus medius ( Mulsant & Rey , 1870)
Dicranocephalus setulosus ( Ferrari , 1874)

supporting documents

Individual evidence

↑ ^a ^b ^c ^d ^e Family Stenocephalidae. Australian Biological Resources Study. Australian Faunal Directory, accessed May 3, 2014 .
↑ ^a ^b Stenocephalidae. Fauna Europaea, accessed May 3, 2014 .
^ Ekkehard Wachmann , Albert Melber, Jürgen Deckert: Bugs. Volume 3: Pentatomomorpha I: Aradoidea (bark bugs), Lygaeoidea (ground bugs, etc.), Pyrrhocoroidea (fire bugs) and Coreoidea (edge bugs, etc.). (= The animal world of Germany and the adjacent parts of the sea according to their characteristics and their way of life . 78th part). Goecke & Evers, Keltern 2007, ISBN 978-3-937783-29-1 , p. 253 ff .
↑ ^a ^b ^c ^d ^e ^f R. T. Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995, pp. 283 ff.
↑ Robert G. Foottit, Peter H. Adler: Insect Biodiversity: Science and Society . Wiley-Blackwell, New York 2009, ISBN 978-1-4051-5142-9 , pp. 241 .
^ TJ Henry: Phylogenetic analysis of family groups within the infraorder Pentatomomorpha (Hemiptera: Heteroptera), with emphasis on the Lygaeoidea. Annals of the Entomological Society of America 90 (3): 275-301, 1997.

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 : Stenocephalidae - collection of images, videos and audio files

[abrs-1] Family Stenocephalidae. Australian Biological Resources Study. Australian Faunal Directory, accessed May 3, 2014 .

[www.faunaeur.org-2] Stenocephalidae. Fauna Europaea, accessed May 3, 2014 .

[Wachmann-3] Ekkehard Wachmann , Albert Melber, Jürgen Deckert: Bugs. Volume 3: Pentatomomorpha I: Aradoidea (bark bugs), Lygaeoidea (ground bugs, etc.), Pyrrhocoroidea (fire bugs) and Coreoidea (edge bugs, etc.). (= The animal world of Germany and the adjacent parts of the sea according to their characteristics and their way of life . 78th part). Goecke & Evers, Keltern 2007, ISBN 978-3-937783-29-1 , p. 253 ff .

[Schuh/Slater-4] ↑ ^a ^b ^c ^d ^e ^f R. T. Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995, pp. 283 ff.

[Biodiversity-5] Robert G. Foottit, Peter H. Adler: Insect Biodiversity: Science and Society . Wiley-Blackwell, New York 2009, ISBN 978-1-4051-5142-9 , pp. 241 .

[Henry-6] TJ Henry: Phylogenetic analysis of family groups within the infraorder Pentatomomorpha (Hemiptera: Heteroptera), with emphasis on the Lygaeoidea. Annals of the Entomological Society of America 90 (3): 275-301, 1997.