Black-spotted grasshopper
| Black-spotted grasshopper | ||||||||||||
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Black-spotted grasshopper, female |
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| Stenobothrus nigromaculatus | ||||||||||||
| ( Herrich-Schaffer , 1840) |
The black-spotted grasshopper or black-spotted heather grasshopper ( Stenobothrus nigromaculatus ) is a short-antennae insect from the family of field locusts (Acrididae). The warmth-loving species that is sensitive to excessive moisture is native to Europe and Asia. Due to the increasing loss of its habitats in Central Europe, it is endangered and has already disappeared in many places.
features
The animals are 13 to 18 millimeters (males) or 18 to 25 millimeters (females) and are therefore slightly smaller than the similar heather grasshopper ( Stenobothrus lineatus ). They have a green, sometimes gray or light brown basic color. Both sexes have orange-red hind rails ( tibia ), in males the end of the abdomen is also often orange-red. The pronotum of the males bears fine light lines along the side keels, in the females these are broad. The wings are brown. Females have significantly shortened wings that do not reach the end of the abdomen. Their wings are significantly narrower than the thighs ( femora ) of the hind legs. Males have only slightly shortened wings that are about the same width as the hind legs and end just before the knees of the hind legs. In contrast to the heather grasshopper, the medial field of the wings is much narrower and noticeably longer than half the wing, the wings do not have a white spot and the wing tips are pointed. Regular cross veins run within the medial field and there are brown-black cube spots, which are more contrasting in the female than in the male. The species owes its German name to these spots. In females, a white line runs along the front margin and the edge of the wing. The males from females can be well by their white button and the long, light gray sensor differ, which are curved toward the tip.
Occurrence and habitat
The black-spotted grasshopper, which originated in Siberia, is common in Europe and Asia. In Europe it occurs locally in Germany, France, Spain, Portugal, Italy (in the Alps and on the Apennines), the Czech Republic, Poland, Switzerland, Austria, in the states of the former Yugoslavia, Romania, Bulgaria and northern Greece. Further east, the occurrence extends across Asia Minor and the Caucasus to Siberia. In Germany, the species is preferred at altitudes between 250 and 900 meters, but it was also found in the Allgäu up to an altitude of almost 1500 meters. The northernmost distribution limit is in the state of Hesse . In Austria it has been detected from Burgenland between 150 and 200 meters, in the southern Alps the species is found at heights of 1600 and 2000 meters. In Switzerland the species occurs at altitudes between 500 and 2270 meters.
The grasshopper occurs in very temperature-favored and dry, sparsely vegetated areas, preferably with a flat bottom. The species is often found on heat islands. It inhabits rocky dry grassland , steppe-like gravel areas and dune areas. At higher altitudes they can be found, for example, on pastures, broom heaths and lawns on southern slopes. They are sensitive to excessive humidity.
Way of life
Like most field locusts, the black-spotted grasshopper feeds on sweet grasses . The animals can only climb poorly and awkwardly and often stay on the ground. You jump at a steep angle and, if disturbed, continue walking in the vegetation on the ground after jumping. Males are more active than females. If it gets cooler or at night they hide in the dense vegetation. During the day you can find the animals in open, sunlit places, where they linger in the evening as long as the temperatures are still favorable there.
Singing and courtship
The song of the black-spotted grasshopper is relatively quiet. In ordinary singing, a one to two second whirring sound is usually repeated three times at intervals of one to two seconds. The buzz swells but ends abruptly. When two males compete with each other, the singing consists of stanzas about five seconds long, often produced at longer intervals, with one male singing during the other's pauses. The singing used in courting a female is varied and includes humming and ticking sounds as well as various movement patterns. The animals only sing during the day when the sun is shining. In cold weather, wind and strong shade, both courtship and mating behavior stop. During courtship, the male approaches his partner within a few millimeters and vibrates with slightly raised hind legs. "Zi zi" and "dr dr" sounds are emitted for several minutes, occasionally the wings are flapped briefly. Then the male suddenly lifts his hind legs, first uttering a sharp “dsch”, then a whirring “drrrrsch”. This whirring sound is similar to ordinary singing, but it is stronger and longer-lasting. The sequence of these two sounds is repeated two or more times, after which the singing begins again with the introduction. The pairing attempts by jumping are accompanied by violent "threshing" sounds.
development
The females lay their eggs in the ground. The larvae live in sheltered places that are well heated by the sun during the day. The first adult animals appear in Central Europe from the end of June / beginning of July, the maximum occurrence is in July and August, the last animals can be found until mid-October.
Hazard and protection
The black-spotted grasshopper is endangered in Central Europe by the changes in its habitat and has already disappeared in many places. Intensive agriculture and the abandonment of sheep pastures, which lead to bush encroachment, are particularly responsible for this. The species is classified as "critically endangered" (Category 2) in the Red List of Threatened Species in Germany. In Austria it is listed as "at risk" (Category 3) on the Red List, in Switzerland it is classified as "Vulnerable" (VU).
In addition to the promotion of herding sheep, the clearing of heather and the associated increase in the duration of tanning is necessary to preserve the habitat of the black-spotted grasshopper. In addition, the grazed areas must be mowed every two to three years in order to reduce old grass stocks and matting.
supporting documents
Individual evidence
- ↑ a b c d e f Heiko Bellmann : The cosmos of locust leader. Determine the species of Central Europe with certainty . Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-10447-8 , pp. 268 f .
- ↑ a b c d e f g h Bertrand & Hannes Baur, Christian & Daniel Roesti: The locusts of Switzerland . Haupt Verlag, Bern 2006, ISBN 3-258-07053-9 , p. 288 f .
- ↑ a b c d e f g h Peter Detzel: The locusts of Baden-Württemberg . Eugen Ulmer, Stuttgart 1998, ISBN 3-8001-3507-8 , pp. 443 ff .
- ^ S. Maas, P. Detzel & A. Staudt: Risk analysis of grasshoppers in Germany. Dissemination atlas, risk classification and protection concepts. BfN-Schriftenvertrieb in Landwirtschaftsverlag Münster, 2002, ISBN 3-7843-3828-3 .
- ↑ K. Adlbauer, A. Kaltenbach: Red list of endangered grasshoppers and crickets, catchy tunes , cockroaches and catching horrors. (Saltatoria, Dermaptera, Blattodea, Mantodea) in: J. Gepp (Red.): Red Lists of Endangered Animals Austria , Green Series of the Federal Ministry f. Environment, Youth and Family, Vol. 2, Vienna 1994.
- ↑ Red list locusts. Red List of Endangered Species. Federal Office for the Environment FOEN: Edition 2007 ( page no longer available , search in web archives: online )
literature
- Bertrand & Hannes Baur, Christian & Daniel Roesti: The locusts of Switzerland . Haupt Verlag, Bern 2006, ISBN 3-258-07053-9 .
- Heiko Bellmann : The Cosmos Locust Leader. Determine the species of Central Europe with certainty . Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-10447-8 .
- Peter Detzel: The locusts of Baden-Württemberg . Eugen Ulmer, Stuttgart 1998, ISBN 3-8001-3507-8 .
