hornet
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Hornet ( Vespa crabro ) |
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| Linnaeus , 1758 |
The hornet ( Vespa crabro ) is a species from the family of the social wasps (Vespidae).
features
The hornet is the largest fold wasp living in Central Europe. The height of the queen is from 23 to 35 millimeters, that of the workers 18 to 25 millimeters and that of the drones 21 to 28 millimeters. As a hornet species, it can be recognized by the shape of the head: When viewed from above, the rear section of the head behind the complex eyes is greatly expanded to the sides, so that the ocelles are further away from the rear edge of the head than from the complex eyes; their distance is more than twice as great.
Another characteristic is shown in the veining of the forewings: Here the first vein (the radial artery Rs ) joins the longitudinal vein (united radius and subcosta) running parallel to the wing edge (combined radius and subcosta) far before the pterostigma or wing mark. In the other genera it opens closely together, less than twice the length of the wing mark.
Usually the hornet is already recognizable by its characteristic color. The head and trunk are black, usually with extensive red or brownish-red markings, the trunk section has no yellow markings. The first tergite of the free abdomen is three-colored only in this species: the front section is red, behind it there is a more or less broad dark spot, the end section is yellow. As with many species of wasp, the rest of the abdomen has black markings of different shapes and dimensions on a yellow background. When looking at the head from the front, the head shield ( clypeus ) is colored pure yellow, the black markings of most other social wasps are missing.
Color variations
In its large area of distribution, the hornet has several variants of coloring and drawing. Some of these occur regionally and have often been described as subspecies by earlier taxonomists . This no longer seems justified today. It is now known that these are not only connected to one another by wide transitions, but that in some cases even individuals with patterns typical of different “subspecies” can appear in the same nest. Today they are predominantly regarded as varieties without taxonomic value. Typical for Central Europe are animals with two V-shaped red longitudinal stripes on top of the middle section of the trunk and a red-colored forehead, known as var. Germana . Especially in northern Europe, animals with a purely black mesonotum and darkened to black forehead, known as var. Crabro , predominate . In England there are some hornets with a predominantly yellow head, the var. Vexator . A number of other color varieties have been described, especially from East Asia.
Possible confusion
The queen of the middle wasp ( Dolichovespula media ) can be mistaken for a hornet worker. It can be distinguished by the color of the tergite (the back plate) of the first free abdomen segment, which is exclusively black and yellow with it, without red or red-brown parts, and the head shield in the middle has a black longitudinal drawing. The other hornet species in Europe (of the genus Vespa ) can be distinguished by the drawing of the abdomen. The oriental hornet, which is widespread in southern Europe and is generally lighter in color, is only shown in yellow on the third and fourth tergites of the abdomen. The Asian hornet , newly introduced from East Asia, has a predominantly black abdomen with a wide yellow band only on the fourth tergite, and its body section is black, always without red or brown parts.
But also completely different insect species such as the hornet swarms , some species of the cudgel sawfly or the hornet hover fly have acquired similarities with hornets in the course of their development. This is interpreted as mimicry , which better protects such alleged imitators from predators.
distribution
The hornet inhabits an area that, compared to other species of the genus, extends further to the west and further north, making it the only species of the genus Vespa that is naturally widespread in Northern and Central Europe . Overall, their settlement area covers large parts of the moderate (temperate) Palearctic , from the Atlantic in the west to Sakhalin , Korea and Japan in the east. In the south it reaches the Mediterranean region, but is locally absent in the warmest, southern sections. It occurs in large parts of south-east Europe, such as the Peloponnese , together ( sympatric ) with the oriental hornet. There is only one old, dubious information from North Africa (Algeria). In East Asia, it is spread much further south in China. In Central Asia it occurs in northern Iran, where it occurs only in the very north, in the region directly on the Caspian Sea . In northern Europe the hornet reaches southern Sweden (up to Limes norrlandicus ) and the extreme south of Norway and Finland, their populations there are declining. In Finland, their occurrence is limited to advances in particularly warm summers; the last record dates from 1973.
In Germany, the species was considered rare and declining for decades, which is why it was included in the Red Lists for a long time . The stocks were concentrated, for example in East Germany, in metropolitan areas, the higher areas of the low mountain range were avoided. The species has been becoming more common again in Germany around the end of the 1970s, it is now widespread almost everywhere and is common locally. The reasons for both the earlier decline and the current recovery are not known. According to, climate changes, declining use of environmental toxins ( DDT ) and the no longer permitted systematic control are to be assumed as possible causes, but not a change in the habitat. However, the same source calls the species a culture follower .
The hornet was introduced to North America as a neozoon by humans around 1840 to 1860. For a long time it was the only hornet species there (the so-called "soon faced hornet" Dolichovespula maculata belongs to a different genus), but other species have since been introduced. It lives here in the east of the continent, west roughly to the Mississippi and Ohio valleys, and reaches Ontario and Quebec in the north. It continues to spread. This is how southern Guatemala was reached in 2005 .
Life cycle and way of life
Only female sex animals, the future queens, overwinter with the hornet. In addition to mated queens, who can establish a new nest in the following year, some unmated sex animals also overwinter. These cannot establish nests. Hibernation sites are mostly crevices or even gnawed cavities in dead wood, few animals hibernate in underground cavities. Hornets hibernate individually, and there are seldom a few animals in the same piece of wood. The hibernation period lasts six to eight months, depending on the local climate and weather.
The activity of the young queens begins in late spring, mostly in April in Central Europe, and not until mid-May in England. They then leave the winter quarters and look for a place to found a nest. Hornets prefer rain-protected, dark cavities such as tree hollows as nest locations. But they also take on artificial places, for example bird nest boxes, attics or tool sheds. Hornets often nest in the same tree hole for several years in a row, but they create a new nest every year, old nests are not reused. The queen starts building the nest on her own, by forming cells from chewed wood fibers in a honeycomb hanging down, which she usually covers with an egg immediately after completion. Soft deadwood , which has become easier to work with due to brown or white rot , is preferred . The nest is often zoned from reddish brown to orange. The nest founder creates an average of 1.6 cells per day. By the time the first workers hatch, it occupies around 40 brood cells. A larva hatches from the egg after approx. 12 to 18 days. This passes through five larval stages and then pupates . The development time of the hornet from the laying of the egg until the worker escapes is about 30 to 50 days. Accordingly, the first workers will not be seen until June. The larvae are fed by the queen and later by the newly hatched workers. Only animal material is used as food, usually captured insects and other arthropods . Since they also occasionally hunt bees , they are unpopular with beekeepers. For their own nutrition, hornet imagines use sugary juices and liquids, especially tree sap on bark injuries, which they expand accordingly, as can be observed in particular on branches of ash and lilacs as thick as a finger - both are olive trees. They very rarely visit flowers. However, they often patrol over well-frequented flower groups to hunt flower visitors there for the care of the brood. In addition to feeding the larvae and the queen, workers also feed each other and thus share the food supply ( trophallaxis ).
After the workers hatch, the queen soon no longer flies out and no longer takes part in looking after the brood. She is also fed by the workers and is limited to laying eggs. However, the losses in the queen phase are very high, so that only a few nests become large. The workers soon put new, horizontally aligned honeycomb plates under the first honeycomb, which the queen herself started, which are connected to one another by several stems (supporting columns) or ribbon-shaped supporting bridges. When fully grown, the nest can often contain six such honeycomb plates; at most, 15 were counted. It then reaches 60 centimeters in length. The whole nest is surrounded by an insulating, more or less thick cover made of the same material as the cells. The nest shell consists of air-filled pockets, the insulation is caused by the still air enclosed in it. In hornet nests, however, which is unusual for wasps, the shell (in Europe, not in Japan) often remains incomplete and open at the bottom, so that the combs are partially exposed. In addition to the nest cover, the animals sometimes partially close the cavity in which the nest lies with a protective wall. If the nest temperature rises too much (ideally 26 ° C), they cool with drafts (flapping wings), and the workers bring in water for cooling. A hornet's nest barely reaches 100 cells by July, but then, with more workers, can quickly grow to around 600 cells in September. At the end of its life, it reaches its maximum size with an average of around 1400 (England) to 1900 cells (Japan). Very large nests go beyond this, in the maximum case up to 2800 cells were counted in Germany and more than 4500 cells in Japan. Due to the limited lifespan of the workers, the number of animals living in the nest at the same time is much lower, and at the height of their number, in September, it was less than 200 on average. The lifespan of a worker is very limited, they survive on average 20, even in favorable cases hardly ever more than 40 days. Hornets can move with their colony if the cavity in which the nest is located - for example a bird nesting box - becomes too narrow. This process is called branch formation .
From around August the people begin to raise new sex animals in addition to workers. These are grown in larger cells, but a certain percentage of the females also develop into workers, some of the males in normal-sized cells. Therefore, the number of sex animals cannot be counted from the large cells. The ratio of females (young queens) to males (drones) is about one to two thirds. A successful colony produces around 200 young queens in the course of its life. The young queens are mated by the drones in autumn, which then die by around the end of October. Around this time, but mostly noticeably earlier, the life of the old queen and the last workers, and with it the nests, also ends.
The Hornet's lodger
The hornet beetle ( Velleius dilatatus ) - or better known as the hornet moth beetle - lives in all stages of development in the waste under the hornet's nest. It feeds on the leftovers of the hornets, but also on dead hornets and fly larvae. So he's a commensal in hornets. Another raven beetle, Quedius brevicornis , also lives as a commensal in hornet nests, but it also eats brood on occasion and can thus become a parasite.
While there are no hornet cuckoo wasps in Europe , a species from East Asia, Vespa dybowskii , is able to penetrate young hornets' nests (from Vespa crabro and Vespa simillima ) in addition to being able to establish an independent nest , to displace their queen and then for the hatching workers to take advantage of oneself and one's own offspring. In some regions, almost half of the nests are taken over by Vespa dybowskii . Vespa dybowskii is closely related to Vespa crabro , possibly its sister species .
Enemies
Because of its size, the hornet has no direct enemies in the insect world. On the other hand, if the population density is too high, competing peoples can damage each other. Birds also belong to the hornets' enemies, but they do not threaten the people themselves directly, but can only prey on individual animals. If, on the other hand, shrews manage to penetrate the nests, this can lead to the complete destruction of the nest, depending on the size of the population and the ability to defend themselves. The caterpillars of the bumblebee nest moth, which are active as brood predators, can irreversibly damage already weakened hornet colonies, so that the colony perishes.
Hornet and human
Danger and stings
The hornet can be a defensive animal when it comes to defending its nest. However, the risk to people and their pets is usually exaggerated - it is much lower than is popularly spread. The saying "7 stitches kill a horse, 3 stitches a person" is incorrect in terms of content. Due to the extreme rarity of massive hornet attacks on humans, a realistic number can hardly be given; In the case of the much more dangerous Vespa orientalis and Vespa affinis , deaths (in non-allergy sufferers) from around 300 bites are reported. The poison dose given off by wasps when stinging humans and other mammals is lower than that of honeybees, since the bee stinging device remains in their skin due to barbs and continues to work automatically. The exact amount of poison released by Vespa crabro has not yet been measured. The toxicity was determined as the LD50 in laboratory mice at around 8.7 to 10.9 milligrams per kilogram of body weight; this value is much higher (i.e. a larger amount is required to cause danger to life, the poison is therefore weaker) than that of most other hornet species and the honeybee. In contrast to the poison composition of other wasps and bees, hornet poison also contains acetylcholine .
On the pain scale of the American entomologist Justin Orvel Schmidt ( Schmidt Sting Pain Index ) the hornet sting is given as 2.0 and thus equal to the sting of the common wasps ( Vespa ) and the honey bee. In contrast to wasps, which often aim at people and can sting unprovoked in unfavorable situations, hornet stings are rare, they occur almost exclusively when approaching the nest carelessly.
Far more dangerous than the normal sting effect is an allergic reaction . The hornet, like other wasp species, can normally trigger this via an IgE reaction. Although the venom of the different species is specifically different, essentially the same allergens have been found in the hornet's venom as in wasp venom, while bee venom has quite different compositions. There is therefore almost always a cross reaction in allergy sufferers , that is, people who are allergic to wasp stings also react to hornet stings and vice versa, while cross reactions are less common in bee allergy sufferers. In addition to the life-threatening systemic anaphylaxis , which is acutely life-threatening even with just one bite, in some cases there is an increased local reaction that goes beyond the usual consequences (red wheals of up to 10 centimeters in diameter); such swelling can last for a few days. The number of people allergic to hornet poison is not known. As with the other species, a rule of thumb is assumed to be around one percent of children and three percent of adults.
Species protection
The hornet is a particularly protected species in Germany according to the Federal Species Protection Ordinance. In Austria, however, it is only protected in Styria and Upper Austria .
Dealing with flying hornets
Hunting or gathering hornets that are not in the immediate vicinity of their nest only sting when they are squeezed. Otherwise they will try to escape.
Hornets don't eat desserts, so you don't get into conflict with them as easily at the coffee table as with other wasp species. However, they occasionally hunt other insects there, such as the German wasp and the common wasp , which eat there and are therefore easy prey for them. The hornets do not disturb afterwards, but mostly fly with their prey to a quieter place, dismantle them and bring them to their nest. They can therefore be tolerated as natural enemies of wasps and flies, which are perceived as annoying at the coffee table.
Dealing with hornet nests
Hornets defend their nest . The defense radius usually varies between two and six meters, depending on the people. If the animals are disturbed frequently, this radius expands. Avoid hectic movements and vibrations such as mowing the lawn within this area. In addition, hornets are stimulated to sting by breathing in or blowing on.
Hornet nests are open at the bottom. The animals simply drop their droppings out of this opening. Since a large colony eats around half a kilogram of insects per day, the droppings below the nest can cause structural damage. As a countermeasure, you can place a large container with absorbent material under it.
Since hornets are under species protection, inhabited nests in the Federal Republic of Germany and some federal states of Austria may not be destroyed. However, if a colony is to be removed, it can usually be resettled by trained people. A special permit is required for this. The municipality or district administration can provide information. By installing special nesting boxes in natural areas remote from settlement, Germany is attempting to make the respective area more attractive for hornets or to make them populable at all by creating artificial nesting spaces. The best-known type of nest box with the best population in terms of results is the so-called " Mündener Hornet Box ".
literature
- Rolf Witt: Wasps. 2nd, revised and expanded edition. Vademecum-Verlag, Oldenburg 2009, ISBN 978-3-9813284-0-0 .
- Rolf Witt: Observe wasps, determine. Nature book. Weltbild, Augsburg 1998, ISBN 3-89440-243-1 .
- Heiko Bellmann : bees, wasps, ants. Hymenoptera of Central Europe. Franckh-Kosmos , Stuttgart 1995, ISBN 3-440-06932-X .
- Robert Ripberger, Claus-Peter Hutter, Berthold Faust: Protect the hornets. The standard work on the protection of hornets and other wasps in Germany, Austria and Switzerland. Weitbrecht, Stuttgart / Vienna 1992, ISBN 3-522-30450-0 .
- Jirí Zahradnik : bees, wasps, ants. The hymenoptera of Central Europe. Franckh-Kosmos, Stuttgart 1985, ISBN 3-440-05445-4 .
Web links
- Diverse, multilingual information page on active hornet protection
- Documentary : When hornets have to move , NaturNah , NDR television , May 14, 2019.
Individual evidence
- ↑ a b Heinrich Kemper, Edith Döring: The social fold wasps of Central Europe. Parey Verlag, Berlin and Hamburg, 1967. Determination table on page 18.
- ↑ Volker Mauss, Reinholdreiber : Identification key for the folded wasps (Hymenoptera: Masarinae, Polistinae, Vespinae) of the Federal Republic of Germany. DJN German Youth Association for Nature Observation, Hamburg, 2nd edition 1995, ISBN 3 923376 17 0 .
- ^ Michael Archer: Key to European Vespinae. BWARS Members' Handbook, 2005, pp. 58-67.
- ↑ Hornets in Great Britain: Vespa crabro vexator Harris, 1776, www.vespa-crabro.de, updated August 3, 2015
- ^ J. Bequaert: The color forms of the common hornet, Vespa crabro Linnaeus. In: Konowia 10, 1931, pp. 101-109.
- ↑ AA Birula: About the Russian wasps and their geographical distribution (first contribution). In: Archive for Natural History (Department A) 90, 1925, pp. 88-102.
- ↑ Werner Arens: The social wasps of the Peloponnese (Hymenoptera: Vespidae: Vespinae, Polistinae), with a description of a new Polistes species and a regional Polistes identification key. In: Linz biological contributions. 43rd volume, no. 1, Linz 2011, pp. 443–481 ( PDF on ZOBODAT ).
- ↑ Ebrahim Ebrahimi, James M. Carpenter: Distribution pattern of the hornets Vespa orientalis and V. crabro in Iran (Hymenoptera: Vespidae). In: Zoology in the Middle East 56, 2012, pp. 63-66.
- ^ Stellan Erlandsson: The distribution of the Hornet (Vespa c. Crabro L.) in northwestern Europe. In: Entomologisk Tidskrift 109, 1988, pp. 155-159.
- ↑ Antti Pekkarinen: The hornet (Vespa crobro L.) in Finland and its changing northern limit in northwestern Europe . In: Entomologisk Tidskrift 110, 1989, pp. 161-164, full text (eng.).
- ↑ Frank Koch: On the stock situation of the hornet (Vespa crabro L.) in East Germany, a retrospective. In: Bembix 11, 1998, pp. 23-26.
- ↑ cf. for example for North Rhine-Westphalia : Horst Woydak: The fold wasps of North Rhine-Westphalia (Hymenoptera, Vespoidea; Vespidae and Eumenidae) (social paper wasps and clay wasps). In: Treatises from the Westphalian Museum of Natural History 68, No. 1, 2006, pp. 1–133.
- ↑ http://www.senckenberg.de/files/nwr/tischendorf_et_el_2013_rl_faltenwespen_hessen.pdf Stefan Tischendorf, Karl-Heinz Schmalz, Hans-Joachim wing, Ulrich Frommer, Wolfgang HO Dorow, Franz Malec: Red List of Hessens Fold Wasps; 1st version (as of June 6, 2013), published on behalf of the Hessian Ministry for the Environment, Energy, Agriculture and Consumer Protection, p. 26
- ^ RD Akre, A. Greene, JF MacDonald, PJ Landolt, HG Davis: Yellowjackets of America North of Mexico . In: US Department of Agriculture, Agriculture Handbook No. 552, 1980, p. 102 ff.
- ↑ Peter J. Landolt, José Monzón Sierra, Thomas R. Unruh, Richard S. Zack: A new species of Vespula, and first record of Vespa crabro L. (Hymenoptera: Vespidae) from Guatemala, Central America. In: Zootaxa 2629, 2010, pp. 61-68.
- ^ Heinrich Kemper & Edith Döring: The social fold wasps of Central Europe. Parey Verlag, Berlin and Hamburg, 1967.
- ↑ Michael Archer: The life history and colonial characteristics of the hornet, Vespa crabro L. (Hym., Vespinae). In: Entomologist's Monthly Magazine 129, 1993, pp. 151-163.
- ^ Roger D. Akre: Social Wasps . In: HR Hermann (Ed.): Social Insects , Volume IV, Academic Press, New York 1982.
- ↑ a b M. Matsuura, S. Yamane: Biology of the Vespine Wasps. Springer-Verlag, Berlin and Heidelberg 1990 (original edition: Hokkaido University Press, 1984), ISBN 3-540-51900-9 .
- ↑ Jerzy Nadolski: Factors restricting the abundance of wasp colonies of the European hornet Vespa crabro and the Saxon wasp Dolichovespula saxonica (Hymenoptera: Vespidae) in an urban area in Poland. In: Entomologica Fennica 24, No. 4, 2013, pp. 204-215.
- ↑ Adrien Perrard, Kurt M. Pickett, Claire Villemant, Jun-ichi Kojima, James Carpenter: Phylogeny of hornets: a total evidence approach (Hymenoptera, Vespidae, Vespinae, Vespa). In: Journal of Hymenoptera Research 32, 2013, pp. 1-15, doi : 10.3897 / JHR.32.4685 .
- ^ The hornet - profile at biologie-schule.de, accessed on June 7, 2020.
- ↑ Natural enemies of wasps , hornets & Co. at aktion-wespenschutz.de, accessed on June 7, 2020.
- ↑ Natural enemies at Umweltbundesamt.de, accessed on June 7, 2020.
- ↑ Hornet www.wespenschutz.ch , accessed on August 17, 2016th
- ^ Richard S. Vetter, P. Kirk Visscher, Scott Camazine: Mass Envenomations by Honey Bees and Wasps. In: Western Journal of Medicine 170, No. 4, 1999, pp. 223-227.
- ↑ Jerzy Nadolski: Effects of the European hornet (Vespa crabro Linnaeus 1761) crude venom on its own species. In: Journal of Venomous Animals and Toxins Including Tropical Diseases 19, 2013, p. 4, doi : 10.1186 / 1678-9199-19-4 .
- ↑ Justin O. Schmidt, Murray S. Blum, William L. Overal: Hemolytic activities of stinging insect venoms. In: Archives of Insect Biochemistry and Physiology 1, No. 2, 1983, pp. 155-160, doi : 10.1002 / arch.940010205 .
- ↑ Mitja Košnik, Peter Korošec, Mira Šilar, Ema Mušiè, Renato Erzen: Wasp venom is appropriate for immunotherapy of patients with allergic reaction to the European hornet sting. In: Croatian Medical Journal 43, No. 1, 2002, pp. 25-27.
- ↑ a b B. M. Bilo, F. Rueff, H. Mosbech, F. Bonifazi, JNG Oude-Elberink: Diagnosis of Hymenoptera venom allergy. EAACI position paper. In: Allergy 60, No. 11, 2005, pp. 1339-1349, doi : 10.1111 / j.1398-9995.2005.00963.x .
- ↑ Ordinance on the protection of wild fauna and flora . Laws on the internet. Retrieved June 23, 2016.