Hornets: Gentle Giants!Bad press - what is true? Responsible Publisher click on thumbnails to enlarge the images The majority of people consider hornets highly dangerous and their presence often causes fear and panic. This arises due to exaggerated stories of hornets attacks and the effect of their stings. "Seven hornet-stings kill a horse, three an adult and two a child ". Such neighbourhood myths, held for generations, have led to the hornet becoming quite rare in many area of Germany, due to merciless human pursuit. Indeed in many regions of Central Europe, the hornet is threatened with extinction! Hornet
(Vespa crabro, Linnaeus 1758) with their aposematic (warning) yellow-black colouring. Shown are their large, highly sensitive main eyes.
These are supported by three simple eyes, so called "Ocelli", which are thought to be horizon detectors,
arranged in a triangle (see the right picture) Description Hornets belong to the order or group Hymenoptera. They are closely related to ants and bees, which are also in the same order. Hymenoptera means joined wings or married wings; Hymen = god of marriage, ptera = wings. The hind wings join to the fore wings with a row of tiny hooks (called hamuli). Like most nest building insects, hornets will defend their colony when they consider it threatened. Therefore, the behaviour of hornets must be roughly divided into two catagories:
In the presence of a hornet, four things should be avoided: rapid movements, blocking the flight path, vibrating or breathing on the nests. With care and calm it is quite possible to study the intimate life of hornets without being stung. For most people a hornet sting represents no special danger. Hornet poison is not more toxic than bee or wasp poison! Some scientific results: Bee poison is chemically and toxically very well investigated, since it is easy to obtain. LD50, the poison component that leads to 50% of cases of death in lab mice, amounts to 6mg poison per kg body weight for bee poison. Reports for hornet poison range from 10mg/kg (HABERMANN 1974) to 90mg/kg (KULIKE 1986), around 1.7 15 weaker than honeybees! (Sources of the scientific results Kulike / Habermann) This explains the autotomous sting of the honey bee, a bee will lose its sting and its life stinging a vertebrate. What it gains is the injection of additional poison from the poison gland which continues to pump on its release. Wasps and hornets use their sting to kill troublesome insect prey. They cannot afford to be wasteful, as they need to be able to sting repeatedly, injecting just about 0.16 - 0,19 mg poison (oven-dry mass). We, hence, have more to fear in the sting of the bee than the hornet! However, the hornet sting contains 5% acetylcholine which stimulate pain fibres more than stings of other wasps and bees. So the sting of a hornet may be a little bit more painful. The hornet lives throughout most of Europe, but is never found north of the 63rd parallel. It is also found in Asia, the United States and Canada.
There are several
geographic color forms of the Hornet found worldwide: J.M. Carpenter, J. Kojima. Checklist of the species in the subfamily Vespinae (Insecta: Hymenoptera: Vespidae). Natural History Bulletin of Ibaraki University 1 (1997), 51-92.
Technically, Vespa crabro is the only hornet in North America, but it did not originate here; it was introduced from Europe. The European hornet was first reported in North America about 1840 in New York state. Since then, it has spread to most of the eastern United States, reaching as far west as Louisiana and the Dakotas. Nowadays it is found in the northeastern quarter of the United States; ranging from Canada, Ontario, North Carolina, Texas, Tennessee and south through the eastern and central US, with scattered sightings extending west of the Mississippi River. The European hornet "Vespa crabro" is the largest vespine in North America. It is the only vespine in the new world that is brown with yellow markings. The vertex of the Vespa crabro is much larger than wasps of the genera Vespula and Dolichovespula. Common names for Hornets in other countries:
Next page: Life cycles of a hornet colony
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