Furrowed steppe weevil
|Furrowed steppe weevil|
Coniocleonus nigrosuturatus ( grooved steppe weevil )
|( Goeze , 1777)|
Coniocleonus nigrosuturatus , sometimescalled the grooved steppe weevil , is a beetle from the family of the weevils (Curculionidae) and the subfamily of the Lixinae . The genus Coniocleonus is represented in Europe with 18 species , some of which are very similar. In particular, Coniocleonus nigrosuturatus resembles the species Coniocleonus pseudobliquus .
The beetle is classified in the Red List of Endangered Animals in Germany in category two (endangered), in Bavaria's Red List of Weevils it is listed in category one (threatened with extinction). In Saxony-Anhalt it is considered to be extinct.
Note on names and synonyms
The species was first described by Goeze in 1777 under the name Curculio nigrosuturatus . Goeze refers to an older French description of the beetle, but the name given there does not comply with the nomenclature rules and the description is therefore not considered to be the first description. In the French description, the beetle is called Charanson à suture noire (weevil with the black seam). The species name nigrosuturatus ( Latin nigro for black and sutura for seam) is just a translation of the French name into Latin. Accordingly, Goeze chose Schwarznaht as the German name for the Beetle. However, the names do not mean that the wing top seam catches the eye as a black line. Rather, in individuals who appear in shades of brown, the wing cover seam is embedded between two pale brown intervals (Fig. 4). In individuals with predominantly black and white markings, the seam is lined with a gray interval on both sides (Fig. 6).
The variant in gray tones of the beetle was described by Fahraeus as a separate species Cleonus leucomelas (gr. Λευκός, leukós, white and μέλας, melás, black, i.e. black and white ). Another synonym is Curculio obliquus (lat. Obliquus oblique , after the course of the ligaments on the elytra) according to a description by Fabricius . The name Plagiographus albirostris is still often used as a synonym for Coniocleonus nigrosuturatus . The beetle described by Chevrolat as Plagiographus albirostris is recognized by Meregalli as Coniocleonus excoriatus after examining the type specimen .
The genus Curculio has been split up several times and differently by different authors. Accordingly, the beetle was temporarily placed in the genus Cleonus , which was defined by Schönherr in 1826. Motschulsky split the genus Cleonus in 1860 and defined the genus Coniocleonus with a key . The name is after Schenkling from the generic name Cleonus and give a wiki. κονία "konía" for "dust" together, but Motschulsky's key gives no indication of what the genus has to do with dust.
Properties of the beetle
|Fig. 4: side view|
|Fig. 5: pronotum from above left (head left),
tinted red: central keel; green tinted: depression;
1 inner bandage (located on top),
2 outer bandage (located on the side)
|Fig. 11: Underside, right worn specimen|
|Fig. 12: Hind tarsus|
The beetle is nine to over fourteen millimeters long and only about three to five millimeters wide. It is black, but the short, close-fitting hairs of different densities made up of simply pointed scaly hair create a lively drawing in shades of brown or shades of gray. However, this does not make the beetle conspicuous, but improves its camouflage. In addition to the dandruff, short hairs also appear in places.
The trunk, which is slightly bent downwards (Fig. 1), is longer than the head and shorter than the pronotum . It is thick, bluntly square, slightly enlarged at the tip, and the sides are parallel to each other. The trunk is hairy whitish on top, largely bald on the sides. On the upper side it has a sharp central keel, which ends at the tip of the trunk in a smooth, slightly raised triangular bald spot (Fig. 2, blue arrowhead). A narrow side keel runs to the side of the central keel. The trunk is sunk in front of the eyes, so that the central keel can be clearly seen. The antennae arise in the front third of the trunk laterally under the expiring side keel. The sensor pits run out towards the front and upwards and just reach the tip of the trunk (in Fig. 2 tinted green). The antenna pits swing down towards the head and end abruptly on the underside of the trunk just before the eyes (in Fig. 3 tinted green). The antennae consist of the shaft, with a kinked whip and club. The shaft reaches the base of the proboscis and is longer than the flagellum. The scourge consists of six limbs. The first link is almost twice as long as the second, the following links are even shorter and the last link is hardly set off against the club. The pointed and dense club is five-limbed. The forehead is only slightly arched. The eyes are elongated, flat, and lateral. They are narrower than the trunk and do not reach the pronotum.
The pronotum is broadest just before the base and narrows slightly rounded towards the front. The posterior edge of the pronotum is pulled back against the tag . The pronotum has a distinct longitudinal keel (tinted red in Fig. 5). This runs through a shallow depression in front and at the back it runs out in a clear longitudinal pit (in Fig. 5 tinted green). The whole top is carved ruggedly, especially at the base next to the longitudinal pit. Four slightly curved longitudinal bands of light hair run parallel to one another over the entire length of the pronotum. The inner (black 1 in Fig. 5) optically continue on the head between the eyes and down to the trunk, while the outer (black 2 in Fig. 5) merge into an area of the same color on the wing covers. The outer bandages on the side are short at the front and tapered downwards and backwards. Laterally, the pronotum is extended forward like a lobe.
The elytra are the same width at the base as the pronotum, but widen noticeably at the shoulders. After that, they hardly narrow at all towards the rear, then significantly in the last third. Each wing cover ends laterally to the seam (in Fig. 7 to 9, green S) with an offset pointed tip (Fig. 9). The two tips gape a little apart.
Most noticeable in the drawing of the wing covers are two diagonal bands on each wing cover. The black color of the two bandages is due to the fact that the beetle is hairless in those places. The bandages run towards the back at about 45 °, where they widen. Together they form a figure that is reminiscent of a small ear of wheat open to the front or a double arrow pointing backwards. The less conspicuous elements of the drawing can be described with the subdivision of each wing cover by ten point strips (numbered in ocher 1,2, ... in Fig. 7 to 10) with slightly increased intervals in between. It is named after the interval between the seam S and the 1st point stripe. This interval is much less densely light-haired than the adjacent intervals and therefore appears uniformly gray, only slightly darker at the base (Fig. 7) and a little lighter at the tip (Fig. 9). Another important element of the drawing is that the first, third and fourth point stripes are deepened and widened like furrows at the base and appear black there due to the lack of hair (Fig. 7). Another feature is a small blunt hump (red arrowhead in Fig. 10). It lies in front of the hairless place where the fourth and fifth row of points converge and the interval between them disappears. In the last third of the first strip of dots, this is also deepened like furrows and black. On the sloping sides of the wing cover there are again less densely hairy intervals.
Initially, the underside is only not hairy at numerous bald spots (Fig. 11 left), in older specimens the hairs can be largely rubbed off (Fig. 11 right). The rear chest is longer than the distance between the rear hips . There is a small, pointed hump in front of the front hips.
The tarsi are four-part. The claws of the claw member are approximated to the base, but extend almost parallel to the outside away from each other. The hind tarsi (in Fig. 12) are narrow, all limbs elongated. The first phalanx is the longest, the second hind tarsal phalanx is considerably longer than the third.
Larva and pupa
The legless larva resembles a maggot . It is slightly curved, white, the head brownish. In the last stage it becomes about 11 to 13 millimeters long. It is round in cross section. The three thoracic and abdominal segments have a very similar structure and can be distinguished from one another mainly by the presence and position of the spiracles . The spiracles sit on the first to eighth abdominal segment laterally near the edge of the preceding body segment. In the chest section there is only one stigma placed laterally between the first and second breast segments. Chest and abdominal segments have transverse bulges on the back, which, together with the bulges on the abdomen, enable movement. The larva is thickest in the fifth and sixth abdominal segment and has a diameter of 4.5 millimeters in the last stage; it tapers almost symmetrically towards the front and back. The tenth abdominal segment is reduced to four anal lobes of different sizes. The dorsal lobe is the largest. There is only one pinpoint eye on each side of the head . The antennae are one-part, membranous with a conical sensory process and three sensillae of different lengths . The upper lip is about twice as wide as it is long.
The doll is eleven to almost twelve millimeters long, at the widest point 4.5 to 5.3 millimeters wide.
The chaetotaxia of larva and pupa can be found in Stejskal et al.
During field observations in Romania, Hungary and Slovakia, the behavior of the species was examined more closely. The beetle occurs in dry and warm locations. It can be found on soils that are hardly or sparsely overgrown, between grasses and herbs near the host plant (name: steppe weevil). The beetle probably avoids locations with denser vegetation because the soil there does not heat up to the extent that it would be necessary for larval development.
There are contradicting statements regarding the host plant. Marcuzzi states that the eating habits are unknown. On the Spanish pages, different genera of thistle are given as feeding plants. In a study of the Ukrainian weevils, the Coniocleonus suturatus is classified as polyphagous on herbs. In Russian publications thyme is often mentioned as the host plant, Reitter states Thymus officinalis as the host plant. In a detailed description of the biology of the beetle from the Czech Republic, however, it is shown on the basis of feeding experiments that thyme is not eaten, but that the beetle presumably lives monophag on the common herons beak . In the search for natural enemies of the arable weed sagebrush ragweed in Hungary, however, it was shown that Coniocleonus suturatus likes to eat the leaves of the weed, which also often causes allergic reactions in humans, and does so severely. In any case, the beetle is largely independent of the chemistry of the soil. It can be found on limestone soils, on sandy and acidic subsoil, heather, dry pasture and grassland, on the roadside, on dikes, in lanes. In a study in 2005, the beetle was one of the dominant beetle species with 6.7% in the gravel steppe Crau in southern France.
The beetle is diurnal and can move very quickly in hot weather. In cool weather he remains motionless. The beetles run across the ground or sit, often in groups, preferably on the leaf rosette of the host plant, both on top, between and below the leaves. The beetle likes to hide, even under stones.
The overwintering beetles appear from early spring. They feed on the leaves of the host plants and mate on them. The males clasp the females tightly and stimulate them by tapping quickly with their middle legs on the rear breast. Although the wings are fully developed, the beetles fly only reluctantly and short distances, so that one also finds the information that they do not fly at all. When disturbed, the beetles drop and pretend to be dead. They are most common and most active from mid-April to mid-May. The development cycle is one year.
The eggs are believed to be laid in the soil near the stems of the host plant. The larvae live in the soil in vertical tunnels near the host plant and feed on the outside of the stem base. The tunnels can be several centimeters long and are round to oval in cross-section with a diameter of four to five millimeters. They end at the surface of the earth. Up to three larvae have been found on the same host plant, but usually only one. The feeding activity is highest in the morning and evening hours and when it is cloudy. During the midday heat, the larvae retreat to deeper sections of the tunnel. At the beginning of July, the larvae pupate a few centimeters below the surface in closed earth chambers. These are inside 25 to 30 millimeters long and 10 to 15 millimeters wide. The beetles overwinter in this chamber or they hatch towards the end of summer, when a second maximum frequency of the beetle can be determined. The beetles feed on the host plant and look for a suitable place to overwinter at the end of summer.
The host plants, which are also well adapted to grazing, are not significantly damaged by the beetle. It is not possible for the beetle to eat roots.
The distribution area extends with gaps from North Africa around the Mediterranean Sea through southern Central Europe to Asia and to Western Siberia . In Europe, the beetle is from Portugal , Spain , France , Belgium , Germany , Switzerland , Austria , Poland , the Czech Republic , Slovakia , Italy , Serbia , Croatia , Hungary , Bulgaria , Romania , Ukraine , Moldova , Albania , Greece , Macedonia , the European Turkey , Southern Russia and the Caucasus, it is also reported from the Mediterranean islands of Sicily , the Balearic Islands and Cyprus . In Asia it is reported from the countries Afghanistan , Armenia , Azerbaijan , Georgia , Israel , India , Iraq , Iran , Jordan , Kyrgyzstan , Kazakhstan , Lebanon , Pakistan , West Bank , Russia , Syria , Tajikistan , Turkmenistan , Turkey and Uzbekistan . In Africa it occurs in Algeria , Egypt , Libya , Morocco and Tunisia .
- Heinz joy , Karl Wilhelm Harde , Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 11 . Rhynchophora (end). Goecke & Evers, Krefeld 1983, ISBN 3-87263-031-8 , pp. 22 .
- Edmund Reitter : Fauna Germanica. The beetles of the German Empire. V. Band, KGLutz Verlag, Stuttgart 1916, , p. 84.
- Klaus Koch : The Beetles of Central Europe . Ed .: Heinz Freude . tape 3 : ecology . Goecke & Evers, Krefeld 1992, ISBN 3-87263-042-3 , pp. 248 .
- Coniocleonus nigrosuturatus and Coniocleonus from Fauna Europaea, accessed on November 22, 2018
- Bayern's Red List of Endangered Weevils (Coleoptera: Curculioidea), p. 165. (nationalredlist.org)
- Red list of weevils (Coleoptera: Curculionoidea) of the state of Saxony-Anhalt, p. 6, version 2004. (lau.sachsen-anhalt.de)
- Johann August Ephraim Goeze: Entomological contributions to the knight Linnaeus' twelfth edition of the natural system. first part, Leipzig 1777, p. 381, no. 49 Curculio nigrosuturatus . (biodiversitylibrary.org)
- Geoffroy (the author is not mentioned until the 2nd edition, 1764): Histoire abregée des insectes que se trouvent environ de Paris. Volume 1, Paris 1762, p. 279, Curculio No. 4, le charanson à suture noire (gdz.sub.uni-goettingen.de)
- CJ Schoenherr: Genera et species Curculionidum. Volume VI, Part 2, Supplementum continens, Paris 1842, p. 52, description of the 89th species of the 211th genus Cleonus leucomelas drawn with FHS. (Farhaeus) (biodiversitylibrary.org)
- Joh. Chr. Fabricius: Entomologiae systematicae, emmendatae et auctae. Volume 1, Hafnia (Copenhagen) 1792, pp. 460, 274. Art Curculio obliquus . (books.google.de)
- Aug. Chevrolat: Mémoire sur les Clionides. In: Mémoires de la Société Royale des Sciences de Liège. 2. Ser. tome 5 Bruselles 1873, Plagiographus albirostris. P. 23, key p. VI ff. (Biodiversitylibrary.org)
- Ivan Löbl, Ales Smetana (ed.): Catalog of Palaearctic Coleoptera Vol. 8: Curculionoidea II. Brill, Leiden 2013, ISBN 978-90-04-25206-6 , p. 99. ( limited preview in Google book search )
- V. Motchoulski: Coléoptères rapport en 1859 par M. Sévertsef the Steppes of méridionales Kirghises, et énumerés par de V. Motschulsky. In: Bulletin de l'Académie impériale des sciences de St.-Pétersbourg. Volume 2, St. Petersburg 1860, p. 539/540 (p. 513 ff, splitting up of Cleonus ) (biodiversitylibrary.org)
- J. Faust: Revision of the group Cléonides vrais. In: German Entomological Journal. Year 1904, Issue 1, p. 177 ff. (P. 283 key for Coniocleonus ) (biodiversitylibrary.org)
- Ernő Csiki: fajaink Cleonus. In: Rovartani lapok. Volume XVI, 1st issue, Budapest 1909, p. 66 ff. (P. 67 key for subgenus and species) (biodiversitylibrary.org)
- Key Curculionidae and Key Cleoninae at coleonet
- R. Stejskal, F. Trnka, J. Skuhrovec: Biology and morphology of immature stages of Coniocleouns nigrosuturatus (Coleoptera: Curculionidae: Lixinae). In: Acta Entomologica Musei Nationalis Pragae. 54 (1), April 2014, pp. 337-354. (researchgate.net)
- Giorgio Marcuzzi: European ecosystem. de Hague / Boston / London 1979, ISBN 90-6193-216-5 , p. 56. ( limited preview in Google book search)
- Species portrait Granada
- Mieczysław Mazur: The distribution and ecology of weevels (Coleoptera: Nemonychidae, Attelabiade, Apionidae; Curculionidae) in western Ukraine. In: Acta zoologica cracoviensia. 45 (3), September 2002, pp. 213-244. (isez.pan.krakow.pl)
- AA Legalov, H. Ghahari, Yu. G. Arzanov: Annotaded Catalog of Curculionid beetles (Coleoptera: Anthribidae ... Curculionidae) of Iran. In: Amurian zoological journal. II (3), 2010, pp. 191-244. (P. 211 thymus as host plant) (attelabidae.narod.ru)
- Horváth Dávid, Kazincsi Gabriella, Keszthelyi Sándor: A Karcsú Répabarkó (Coniocleonus nigrosuturatus), a parlagfü természetes ellensége. In: Növényvédelem. 50 (8), 2014. (academia.edu)
- Sylvain Fadda include: Consequences of the cessation of 300 years of grazing on dry Mediterranean grassland ground-active beetle assemblages. at ScienceDirect. CR Biologies. 331, 2008, pp. 532-546.
- International Weevil Community Website Revision July 13, 2017