Asian giant hornet
| Asian giant hornet | ||||||||||||
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Asian giant hornet |
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| Vespa mandarinia | ||||||||||||
| Smith , 1852 |
The Asian giant hornet ( Vespa mandarinia ) is a hornet species found in East and Southeast Asia . Asian giant hornets are up to five times larger than western honey bees . A sting from the giant hornet is described as extremely painful. In Japan , an average of 40 people die each year from an allergic reaction to the stings of its largest subspecies, the Japanese giant hornet ( Vespa mandarinia japonica , Japanese Ōsuzumebachi ( オ オ ス ズ メ バ チ / 大 雀 蜂 ) 'large sparrow bee ').
features
Workers are 27–45 mm in length, queens up to 55 mm. The workers have a wingspan of about 76 mm and a 6 mm long venomous sting . The head is orange and relatively broad compared to other hornets. Compound eyes and ocelles are dark brown, the antennae gray-brown with an orange shaft. The front plate is orange with narrow bulges in the rear. The mandibles are orange-brown with black teeth. The thorax and propodeum have a golden hue. The two-part scutellum is large with a deep-drawn groove in the middle. The front pair of legs is dark orange with dark brown tarsi , the middle and rear legs are dark brown. The gaster is dark brown with a powdery white coating and narrow yellow bands on the rear edges of the tergite , only the sixth segment is completely yellow. The poison sting has no barbs and can therefore be used multiple times. The poison contains a high concentration of acetylcholine .
Geographical distribution
The Asian giant hornet is particularly common in rural areas of Japan . It is also found in the southeastern part of Asian Russia , the southern regions of Primorsky Krai , as well as in Korea ( Korean 장수 말벌 jangsumalbeol , "long-lived wasp"), China ( Chinese 虎頭 蜂 , Pinyin Hǔ tóu fēng , "tiger head bee") called), Indochina , Nepal , Bhutan , India and Sri Lanka .
Alleged sightings of this species in other parts of the world, for example in Europe or Mexico , have always been based on incorrect assignments of other hornet species such as Vespa orientalis (Oriental hornet) and Vespa velutina ; in particular, an invasion of the smaller species Velutina from France has been observed in Europe since 2004 . Sightings have been recorded in the United States and Canada since the fall of 2019.
Way of life
Development of a colony
Vespa mandarinia prefers to nest in underground cavities. If aboveground nesting sites (tree hollows or similar) are occasionally used, these are rarely more than 1–2 m above the ground.
The queen's eggs develop into larvae after about a week . The larvae scrape the cell walls with their mouthparts to give the queen the signal to search for food. This brings suitable prey animals, mainly insects, which are decapitated with the sharp upper jaw pincers and chewed into a soft food mass, from which the queen also eats something to cover the protein requirement necessary for the breeding activity. The later hatching workers take care of the brood in a similar way. On the basis of chewed prey, the larvae grow up quickly and pass into the pupal stage . In the fall of each year and male animals that hatch drones that shortly after mating the young queens die.
At the beginning of the colder season, the hornet colonies die - only the young queens survive in a protected winter quarters with a suitable microclimate . In the following spring they fly out to look for a place for a new nest.
nutrition
The hatched hornet worker no longer grows and does not need any protein herself, but due to her massive body and the energy-intensive flight activity, she has a high need for sugar , which, in addition to eating the digestive substances of the prey, can initially also be met by visiting flowers. Like all wasps workers, the feed imagines almost exclusively vegetarian , primarily from sugar and pollen . Sources of protein are primarily needed to feed the offspring. The strong cheeks of the Vespa mandarinia are striking . Behind it is a well-developed chewing muscles that enable the hornet to hunt medium-sized to large beetles as main prey and then to cut them up for their brood. As the season progresses, however, in Japan usually from the end of August, when such beetles are more and more sparsely captured and are no longer sufficient to supply the growing colony, the Vespa mandarinia adjusts to new sources of protein. Since the need for protein and sugar increases sharply with the growth of the colony and the attraction of the physically even larger sex animal larvae, she now prefers to turn to honeybees, which in addition to their protein-rich body substance, which is fed to the offspring, mostly also over collected nectar, honey and pollen and at the same time are suitable for supplying workers and offspring. This way of life makes the giant hornet a serious threat to the much smaller honeybees. But wasp and other hornet colonies are also potential prey, for example the smaller wasp species Vespa affinis or Vespa dybowskii .
Hunting behavior
Towards the end of the Japanese summer, coordinated mass attacks by the Asian giant hornet on the nests of smaller wasps and bees occur. First, individual giant hornet scouts undertake longer search flights and mark a suitable nest with scents, the pheromones . The recruitment of nest mates is rare for wasp species and otherwise known for bees. Following the pheromone, more workers now attack the nest. The hornets use their well-developed mouthparts and are largely protected from the defensive spines of the wasps and bees by a strong chitin armor . The losses of attacked bee colonies are extremely high (an average of 40 animals per minute) and can even result in the extinction of the entire bee colony. Overwhelmed nests are often extensively looted and destroyed. This makes the Asian giant hornet very unpopular with local beekeepers .
The eastern honey bee ( Apis cerana ) native to Japan has - unlike the introduced western honey bee ( Apis mellifera ) - developed effective prevention against such attacks. If the bees discover a hornet scout, they signal with a tremor in their abdomen that a counterattack should be initiated. Several hundred bees then pounce on the hornet in a flash and create a ball of heat - a ball-shaped swarm - around the hornet. Inside the crowd, muscle tremors generate a temperature of over 45 ° C, at which the hornet scout dies, while the bees can withstand temperatures of up to 50 ° C for a short time due to a different metabolism . More recent studies assume that the increased CO 2 concentration in the heat sphere also contributes to the death of the hornets. Other colonizing hymenoptera, including the western honeybee, are usually unable to defend themselves effectively against the Asian giant hornet.
Enemies
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Due to its ability to defend itself, the Asian giant hornet has comparatively few natural enemies and is also dominant over all other colonizing bees and wasps (including other hornets) with which it shares its habitat. However, it is possible that rival peoples of the Asian Giant Hornet attack each other.
Other enemies of this hornet species are wasp buzzards (genus Pernis ), especially the European honey buzzard ( Pernis ptilorhynchus ), which, like the other species of the genus, specializes in colonizing hymenoptera and has dense plumage, which means it is well protected from hornet stings. The birds of this genus can also approach the nests of the hornets unhindered and then plunder them.
Although the prey spectrum of the hornet also includes fishing hornets , individual individuals of the Asian giant hornet can also be specimens of larger representatives of this order, e.g. of the Great Chinese Mantis ( Tenodera sinensis ). The eastern honey bee can defend itself against individual scouts of the hornet, which invade their nest. One parasite that specializes in the Asian giant hornet is the fan- winged Xenos moutoni .
The greatest threat to the Asian giant hornet, however, comes from humans, who often classify the hornet as a nuisance or beekeeping pest and try to control it. (See chapter Significance for humans ).
Importance to humans
Because of the high aggressiveness of the giant hornet against colony-forming insects, this is particularly combated by beekeepers. Since western honey bees produce significantly more honey than the native Asian bee, many beekeepers are more likely to resort to chemical pest agents instead of switching back to the eastern bees. However, the aggressiveness towards humans is far less than often assumed. The main fatalities are those with allergies, who can suffer a circulatory collapse due to general allergic reactions to the poison.
In Japan, an average of 40 people die each year from the Japanese giant hornet sting. In 2013, 42 people were killed in attacks by Asian giant hornets in Shaanxi Province , China. The attacks on people mostly result from wrong behavior towards the animals (hit at them, blow away or step on them). Only when defending the nest do the animals sometimes react aggressively.
literature
- Steve Backshall: Steve Backshall's Venom: Poisonous Animals in the Natural World . New Holland Publishers, London 2007, ISBN 1845377346 .
Individual evidence
- ^ Brian Handwerk: "Hornets From Hell" Offer Real-Life Fright . National Geographic News. October 25, 2002. Retrieved November 9, 2011.
- ↑ a b c Asian giant hornet . Website hornissenschutz.de. August 15, 2011. Retrieved November 9, 2011.
- ↑ a b Steve Backshall: Steve Backshall's Venom . P. 147ff.
- ↑ James M. Carpenter, Jun-ichi Kojima: Checklist of the species in the subfamily Vespinae (Insecta: Hymenoptera: Vespidae). In: Natural History Bulletin of Ibaraki University. No. 1, 1997, pp. 51-92, online (PDF; 2.85 MB) .
- ↑ Exotic hoornaar vestigt zich in Nederland - NPO Radio 1. In: nporadio1.nl . Retrieved September 23, 2017 .
- ^ Mike Baker: 'Murder Hornets' in the US: The Rush to Stop the Asian Giant Hornet . In: The New York Times . May 2, 2020, ISSN 0362-4331 ( nytimes.com [accessed May 3, 2020]).
- ↑ M. Ono, T. Igarashi, E. Ohno, M. Sasaki: Unusual thermal defense by a honeybee against mass attack by hornets (Vespa mandarinia japonica). In: Nature . (1995) 377, pp. 334-336.
- ↑ Michio Sugahara, Fumio Sakamoto: Heat and carbon dioxide generated by honeybees jointly act to kill hornets. Natural Sciences, September 2009, Volume 96, Issue 9, pages 1133–1136.
- ↑ Description of the Asian giant hornet on Animal Diversity Web ( Link )
- ↑ Description of the Great Chinese Mantis on PRAYING-MANTIS.org ( Link )
- ↑ Description of the Asian giant hornet on Animal Diversity Web ( Link )
- ↑ Description of the Asian giant hornet on Animal Diversity Web ( Link )
- ↑ Der Spiegel: China - Giant hornets kill more than 40 people (video).
