Ips (beetle)
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| De Geer , 1775 |
Ips is a genus of bark beetles (Scolytinae) with a Holarctic distribution. It includes around 35 species, 6 of which are also found in Europe. They live on conifers, especially of the genera Pinus ( pine ) and Picea ( spruce ). Some species are economically important forest pests .
Generic description
The adults are between 2.2 and 8.2 millimeters long. The uniformly arched pronotum is large and hides the head when viewed from above, its base is simply dotted or smooth, the front part has cusps. The eyes are kidney-shaped. The antennae is five-membered and the sutures of the antennae are curved. The first space between the rows of dots on the wing-coverts bears a row of fine granules before the fall. The fall itself forms a shallow trough, its edge is studded with teeth, and it slopes obliquely from the middle of the wing cover towards the end. The second tooth on the fall is a bevel tooth. The tip edge of the elytra is double, the inner edge encompasses the abdomen , and the outer edge limits the fall. From the second sternite towards the end, the abdomen remains almost straight. The front rails are serrated on the outside. The third foot link is cylindrical. Sexual dimorphism exists between the male and female imago : the male has a stronger frontal cusp and stronger teeth at the edge of the fall as well as shorter hair in the middle of the seventh sternite than the female.
distribution
According to the more recent taxonomic revisions, the genus contains 36 species. Of these, 23 live in North and Central America and 13 in Asia and Europe. Of the species of the Old World, 6 are also found in Europe (the black pine bark beetle , which was previously classified as the seventh species in the genus, was transferred to another genus as Orthotomicus mannsfeldi ). The remaining Eurasian species are mainly known from the Himalayas and China, where other, as yet undescribed species are suspected. It is not known whether the Asian species Ips subelongatus , which lives mainly on larches ( Larix ), may have been introduced to Europe, as it has so far mostly been confused with the European Ips cembrae ( large larch bark beetle ) and there is no definitive evidence.
Phylogeny and Taxonomy
The genus Ips was in 1775 by the Swedish entomologists Carl De Geer described , type species is, by subsequent establishment of Ernst Evald Bergenroth , Ips typographus (originally described as Dermestes typographus Linnaeus later Tomicus typographus ). From the originally very broad genus, numerous species have been separated into other genera. In the modern expansion, the genus was determined by phylogenomic studies (determination of the relationships based on the comparison of homologous DNA sequences). In order for the genus to become monophyletic , a number of species and groups of species had to be separated and transferred to other genera. At the same time, a number of species previously described but later synonymized by other taxonomists were restored. According to the results, the Eurasian species do not form a closed community of descent compared to the American ones. The genus was divided into a number of sub-genera. The previously differentiated groups of species were, with a few exceptions, clearly recognized as artificially composed units.
The following synonyms are known from the literature for the genus Ips : Cumatotomicus Ferrari, 1867, Cyrtotomicus Ferrari, 1867.
Species in Europe
The following six species all occur in Europe and Germany . More details on the respective distribution among the species.
- Six-toothed pine bark beetle ( Ips acuminatus ) (Gyllenhal, 1827)
- Small eight-toothed spruce bark beetle ( Ips amitinus ) (Eichhoff, 1871)
- Large larch bark beetle or eight-toothed larch bark beetle ( Ips cembrae ) (Heer, 1836)
- Nordic spruce bark beetle ( Ips duplicatus ) (Sahlberg, 1836)
- Twelve-toothed pine bark beetle or large twelve-toothed pine bark beetle ( Ips sexdentatus ) (Boerner, 1767)
- Letterpress or large eight-toothed spruce bark beetle ( Ips typographus ) (Linnaeus, 1758)
Forestry importance
Since they set up their breeding systems in the bark of the host trees, they are counted among the bark breeders. Of all European bark beetles, some species of the genus Ips have the greatest tendency to mass reproduce in lying wood, in storms or snow throws and breaks, but also in standing conifers that have been weakened by drought , insect damage or abiotic influences. These can then switch to completely healthy trees and cause epidemics on a large scale. From a forestry point of view, bark beetles therefore have a very high damage potential in pure coniferous wood stands . Forestry damage occurs, among other things, from:
- the forced use of the infested trees often well before reaching the harvest age and
- the associated loss of wood, as the trees could continue to grow for several years ( loss of growth ),
- increased expenses due to irregular wood production (increased transport and processing costs ),
- Loss of quality of the wood through the subsequent penetration of fungi ( blue stain ) or other beetles such as longhorn beetles and / or other wood-eating insects (technical devaluation).
If the foci of infestation are not removed quickly, there can be mass reproductions that can reach enormous proportions ( Bavarian Forest National Park ). More information about the consequences under bark beetles .
Ecological importance
Due to the tendency to cause even completely healthy trees to die in the event of mass reproduction, the beetles can dissolve or loosen closed monocultures and give other tree species the opportunity to spread again through the incidence of light on the forest floor. They also create an abundant supply of standing and lying dead wood . In this way, they can indirectly create the conditions for increasing biodiversity .
swell
Individual evidence
- ↑ Lawrence R. Kirkendall & Massimo Faccoli (2010): Bark beetles and pinhole borers (Curculionidae, Scolytinae, Platypodinae) alien to Europe. ZooKeys 56: 227-251. doi : 10.3897 / zookeys.56.529
- ^ Christian Staufer: A Molecular Method for Differentiating Sibling Species within the Genus Ips. In: JC Grégoire, AM Liebhold, FM Stephen, KR Day, and SM Salom (editors) (1997): Proceedings: Integrating cultural tactics into the management of bark beetle and reforestation pests. USDA Forest Service General Technical Report NE-236: 87-91.
- ↑ Anthony I. Cognato & Felix AH Sperling (2000): Phylogeny of Ips DeGeer Species (Coleoptera: Scolytidae) Inferred from Mitochondrial Cytochrome Oxidase I DNA Sequence. Molecular Phylogenetics and Evolution 14 (3): 445-460. doi : 10.1006 / mpev.1999.0705
- ^ Antony I. Cognato & Alfried P. Vogler (2001): Exploring Data Interaction and Nucleotide Alignment in a Multiple Gene Analysis of Ips (Coleoptera: Scolytinae). Systematic Biology 50 (6): 758-780.
- ↑ Donald E. Bright (2014): A Catalog of Scolytidae and Platypodidae (Coleoptera), Supplement 3 (2000-2010), with notes on subfamily and tribal reclassifications. Insecta Mundi 861, 336 pp.
- ↑ Steven L. Wood (1982): The Bark and Ambrosia Beetles of North and Central America (Coleoptera: Scolytidae), a Taxonomic Monograph. Great Basin Naturalist Memoirs 6. 1359 pp. download at archive.org ( Memento of the original from August 20, 2016 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
literature
- Sabine Grüne : Handbook for the determination of the European bark beetles , Verlag M. & H. Schaper, Hannover 1979, ISBN 3-7944-0103-4 .
- Edmund Reitter : Fauna Germanica - The beetles of the German Empire. Volume 5, KG Lutz, Stuttgart 1916.
- Edmund Reitter: Fauna Germanica - The beetles of the German Empire. 5 volumes, KG Lutz (Stuttgart 1908–1916), digital library volume 134, Directmedia Publishing GmbH, Berlin 2006, ISBN 3-89853-534-7 .
- Erwin Stresemann : Excursion fauna for the areas of the GDR and the FRG, Volume 2.1, invertebrates, insects-first part , people and knowledge Volkseigener Verlag, Berlin 1989, ISBN 3-06-012522-8 .
- Fritz Schwerdtfeger : The forest diseases. Textbook of forest pathology and forest protection. 4th, revised edition. Parey, Hamburg / Berlin 1981, ISBN 3-490-09116-7 .
