Hawthorn weevil
| Hawthorn weevil | ||||||||||||
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Hawthorn weevil |
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| Scientific name | ||||||||||||
| Otiorhynchus crataegi | ||||||||||||
| Germar , 1824 |
The hawthorn vine weevil or bush vine weevil ( Otiorhynchus crataegi ) is a beetle from the family of weevils and the subfamily Entiminae . The genus Otiorhynchus is represented in Europe with 77 subgenus, Otiorhynchus crataegi is counted to the subgenus Pocodalemes , which is represented in Europe with three species.
   
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| Fig. 1: Different views | |
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| Fig. 2: Detail of the pronotum |
Fig. 3: Detail of the wing cover, scales and bristle hairs |
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| Fig. 4: Front leg, arrows see text |
Fig. 5: Feeler 2nd link of the hostage tinted green |
Notes on names and synonyms
The beetle was first described by Germar in 1824 . Germar adds Dahlii to the name Otiorhynchus crataegi . Presumably the entomologist Georg Dahl provided the material on which the description is based. The species name crataegi is derived from Crataegus . Crataegus is the scientific name for one of the beetles' feeding plants, the hawthorn. Since the hawthorn is not characteristic as a feeding plant, the name bush weevil is also used in addition to the German name hawthorn black weevil. Germar himself does not explain the species name. In the same publication, Germar introduces the new genus Otiorhýnchus . The name is from altgr. ωτίον "otíon" for "little ears" and ρυνχος "rhynchos" for "proboscis" derived. Germar goes into the description of the genus several times on the flap-like widening of the trunk tip, which explains the name. The genus was temporarily divided into six subgenera and the hawthorn vine weevil assigned to the suborder Tourniēria . This is named after Henri Tournier in Peney near Geneva . Upon further splitting, the species was placed in the subgenus Pocodalemes . The name goes back to Edmund Reitter . Reitter does not explain the name, but notes that it largely follows the division of Wilhelm Gustav Stierlin . At Stierlin, the sub-genera are divided into groups that are simply numbered. The hawthorn weevil is assigned to the 18th group by Stierlin. Reitter gives the Rotten names, whereby he partially divides them up. Regarding the names Reitter remarks: Anyone who does not approve of these names can simply ignore them . A comparison with the other names given by Reitter in this context for the Rotten at Stierlin allows the conclusion that the names are predominantly word formations without meaning.
Synonyms are not known.
Characteristics of the beetle
The beetle becomes five to six millimeters long. The head, pronotum and underside are dark brown, the wing covers , legs and antennae are a little lighter brown. Lighter scales in different densities make the wing covers appear spotty, while bristly hair makes the beetle look shaggy.
The head is broad and flat. In contrast to Otiorhynchus rotundatus, the eyes are rather curved. The trunk is stretched forward and is slightly shorter and narrower than the head. It is flat, no longer than wide and has a very fine, short central keel. The slender antennae (Fig. 5) are turned into a rounded pit near the tip of the trunk. This sensor pit is short, wide, only deepened at the front, and can be completely seen from above. The antennae are half the length of the body and are kneeling. The base segment ( scapus ) is almost as long as the rest of the antennae. All seven limbs of the Scourge are more or less stretched. The second limb of the flagellum (tinted green in Fig. 5) is a third longer than the first, the last limb of the flagellum is significantly longer than it is wide. The final antenna lobe is elongated and pointed.
The small pronotum is a little wider than it is long and moderately rounded on the sides. It is densely napped with round, hump-like elevations on which a bristle usually sits (Fig. 2). A weak longitudinal channel can be formed in the middle
A label is not visible.
The elytra together are hardly longer than wide and twice as wide as the pronotum. They are almost spherical. They are protruding with bristly hairs and in places covered with very small, light-colored scales between the hairs (Fig. 3). The scales are at most occasionally narrow and pointed, usually rounded. Their distribution over the wing cover causes a marbling. The wing covers have ten broad longitudinal rows from a few eye points. The intervals are all equally high and narrower than the point stripes. They each have only one row of upright bristle hairs. There is no callous hump at the tip of the wing-coverts, but the wings are granular at the wing-drop.
The legs are medium long and strong. In all tarsi the 4th link is stunted, they appear to be four-link (pseudotetramer). The claws are not overgrown. The front rails are at most angularly widened towards the inside, the outer edge is bent inwards to straight at the point (Fig. 4 green arrowhead). All thighs have a pointed tooth on the inside, the tooth on the fore thigh is multi-pointed (Fig. 4 blue arrowhead).
biology
The finished beetles can be found from April to October. They are nocturnal and then quite nimble. During the day, the beetles hide under the bushes in the leaves, also in compost, and are then very sluggish. When disturbed, they pull up their legs and pretend to be dead. The larvae feed on roots.
In contrast to the majority of most weevils, the hawthorn vine weevil is not very specialized in its food plants. The beetle in gardens and parks preferentially gnaws at the deeper leaves of various shrubs and small trees in a characteristic way. Lilac , privet snowberry but also numerous neighboring bushes ( honeysuckle , ash , snowball , dogwood , sorrel , cotoneaster ) are used as a source of food. The eponymous hawthorn is not preferred to be visited.
The leaf damage (Fig. 6) initially creates semicircular bays on the leaf edge. One can find leaves that are knurled all around like gears of such bays (Fig. 6 Fig. 5). Later the feeding bays are driven deeper into the leaf, if the infestation is severe, the leaves can be completely eaten away (Fig. 6 Fig. 3). The beetle is now classified as a pest for ornamental shrubs in certain areas and control measures are recommended.
Numerous eggs are laid in September. The eggs are almost spherical (0.7 by 0.5 millimeters) and have a strong gloss. They are initially milk white, later they turn light brownish-yellow to red-yellow. They are exceptionally stable and resilient and roll away easily if you try to manipulate them. As the egg matures, the head of the larva becomes visible. At the beginning of October you can find hatched larvae. They are legless but can crawl well.
Occurrence
The species was previously only known from Romania , Yugoslavia and Italy , today it is also more widespread in Central Europe ( Luxembourg , Germany , Austria , France , Great Britain , Denmark , Switzerland ). In addition, in the Fauna Europaea Bosnia-Herzegovina , Bulgaria , Croatia, the Czech Republic , Denmark and Finland and the Middle East are included in the distribution area. The beetle has now also been reported from Belgium and the Netherlands . The species is counted among the invasive species, in Sweden it is classified as an expected species .
literature
- Heinz joy , Karl Wilhelm Harde , Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 10 : Bruchidae – Curculionidae 1 . Goecke & Evers , Krefeld 1981, ISBN 3-87263-029-6 . P. 223
- Klaus Koch : The Beetles of Central Europe . Ed .: Heinz Freude . tape 3 : ecology . Goecke & Evers, Krefeld 1992, ISBN 3-87263-042-3 . P. 213
Individual evidence
- ↑ a b Fauna Europaea systematics and distribution of Otiorhynchus crataetus , accessed on June 12, 2017
- ↑ a b Germar : Insectorum species - novae aut minus cognitae - descriptonibus illustratae Halle 1824 Otiorhynchus crataegi p. 366, no. 507 and the new genus Otiorhynchus p. 343
- ^ A b Sigmund Schenkling: Nomenclator coleopterologicus 2nd edition, Jena 1922
- ^ A b G. Stierlin: Revision of the European Otiorhynchus species , special edition of the Berlin Entomologische Zeitung Berlin 1861 No. 192 Otiorhynchus crataegi in the Google book search
- ↑ a b Edmund Reitter: Overview of the subgenera and the species groups of the genus Otiorhynchus GERM. in Wiener entomologische Zeitung 31st year Vienna 1912 p. 46 top section last sentence: arbitrariness of names and p. 60 pocodalemes
- ↑ Identification tables from coleo-net sub-genus Tournieria , accessed on June 18, 2017
- ^ Ludwig Redtenbacher: Fauna Austriaca - Die Käfer 3rd edition, 2nd volume, Vienna 1874, p. 220
- ↑ a b c Franz Heikertinger: " Otiorhynchus crataegi Germ-. And mastix Ol, two ornamental shrub pests in the Vienna Gardens" in negotiations of the Zoological-Botanical Society in Vienna 73rd volume, Vienna 1932, pp. 119–128
- ↑ David V. Alford: Pests of Ornamental Trees, Shrubs and Flowers 2nd Edition London 2012, ISBN 978-0-12-398515-6 , p. 162, no. 344.
- ↑ Attractants for different species of black weevil Schleswig Holstein Chamber of Agriculture: Test reports in German horticulture PDF
- ↑ E. Palm: " Otiorhynchus (Tourneria) crataegi found in The Netherlands (Coleoptera: Curculionidae) in Entomological Reports Vol. 58, No. 10, pp. 205-206
- ↑ Drumont, Limbourg et al. Contribution à l'étude des Otiorhynchus Germar, 1822 de la Région Bruxelles-Capitale et note sur l'espèce invasive o. Crataegi Germar, 1824 Coleoptera: Curculionidae in Bulletin de la Société royale belge d'Entomologie 152 (2016): 51-61 [1]
- ↑ Christoffer Fägerström, Elisabeth Kärnestam, Rana Anderson Nya och förwäntade öronvivelarter (Coleoptera Otiorhynchini) på prydnadsbuskar i Scerige in Entomolgisk Tidskrift 131 (1) 37-48, Uppsala 2010, ISSN 0013-886X in the abstract
