Asian giant
hornet
The Asian giant hornet (Vespa mandarinia), the world's largest
hornet, is a native to the mountains of Japan. Its body length is
between 27 mm (1.1 inches) and 45 mm (1.8 inches), with a wingspan
of about 76 mm (3 inches). Queens may reach a length of 55 mm (2.2
inches).
Asian giant
hornet, Vespa mandarinia
Anatomy
The head of the hornet is orange and quite wide in comparison to
other hornet species. The compound eyes and ocelli are dark brown,
and the antennae are dark brown with orange scapes. The clypeus
(the shield-like plate on the front of the head) is orange and
coarsely punctured; the posterior side of the clypeus has narrow,
rounded lobes. The mandible is large and orange with a black tooth
(inner biting surface).
The thorax and propodeum (the segment which forms the posterior
part of the thorax) of the Asian giant hornet has a distinctive
golden tint and a large scutellum (a shield-like scale on the
thorax) that has a deeply-impressed medial line; the postscutellum
(the plate behind the scutellum) bulges and overhangs the
propodeum. The hornet's forelegs are orange with dark brown tarsi
(the distal - furthest down - part of the leg); the midlegs and
hindlegs are dark brown. Wings are a dark brownish-gray. The
tegulae are brown.
The gaster (the portion of the abdomen behind the thorax-abdomen
connection) is dark brown with a white, powdery covering; with
narrow yellow bands at the posterior margins of the tergite, the
sixth segment is entirely yellow.
Geographic Distribution
It can be found in most of Asia but mostly in the mountains of
Japan: southeastern regions of Asian Russia (Primorskii Krai),
Korea, China, Japan, Indochina, Nepal, India, Sri Lanka.
"Hornets From Hell"
Sting
The stinger of the Asian giant hornet is about a quarter-inch (6
mm) in length, and injects an especially potent venom that contains
an enzyme so strong that it can dissolve human tissue. Masato Ono,
an entomologist at Tamagawa University near Tokyo, described the
sensation as feeling "like a hot nail through my leg."
If a person is stung by the giant hornet and does not receive
prompt medical treatment, he or she may die from a reaction to the
venom. About 40 people die each year after being stung by giant
hornets, mainly as a result of an allergic reaction to the
venom.
A couple of interesting notes on the V. mandarinia's venom and
stinger:
- The venom contains 5% acetylcholine, which stimulates the pain
nerve fibres more than bee or other wasp venoms, so that it is a
bit more painful.
- The venom is optimized to kill bees which are the V. mandarinia's natural prey. This
means that while the venom may be a bit more painful to
vertebrates, it is actually less toxic.
- Like all hornets, V.
mandarinia can sting repeatedly, and do so when they prey on
bees and other insects.
- According to a report, one victim could not be recognized because
said victim's face was dissolved beyond recognition due to numerous
stings to that area.
Predation
The Asian giant hornet is a relentless hunter that preys on other
large insects such as bees, other hornet species, and praying
mantises.
The hornets often attack honeybee hives with the goal of obtaining
the honeybee larvae. The hornets can devastate a colony of
honeybees: a single hornet can kill as many as 40 honeybees
per minute; it takes only
a few of these hornets a few hours to exterminate the population of
a 30,000-member honeybee hive, leaving a trail of severed insect
heads and limbs. Once a hive is emptied of all defending bees, the
hornets carry the honeybee larvae back to feed to their own
larvae.
A giant hornet attacks a honeybee
hive.
Rather than consume their kills directly, the hornets chew them
into a paste and feed them to their larvae. The hornet larvae, in
return, produce a clear liquid which the adults consume (see
The Hornet and the Japanese
Diet, below).
Native
Honeybees
Although a handful of Asian giant hornets can easily defeat the
defenses of honeybees, whose correspondingly small sting cannot
inflict much damage against such a large predator as the giant
hornet, the Japanese honeybee (Apis cerana japonica) has evolved an
ingenious method of defending against the much larger
predator.
When a hornet scout locates a Japanese honeybee hive and approaches
the nest, the scout will emit specific pheromonal hunting signals.
When the honeybees detect these pheromones, a hundred or so
honeybees will gather near the entrance of the nest, apparently to
draw the hornet further into the hive. As the hornet enters the
nest, a large mob of about five hundred honeybees surround the
hornet, completely covering it and preventing it from moving, and
begin quickly vibrating their flight muscles. This has the effect
of raising the temperature of the honeybee mass to 47 °C (116.6
°F). Though the honeybees can tolerate such a temperature, it is
fatal to the intruder, which can handle a maximum temperature of
about 45 °C/113 °F, and is effectively baked to death by the large
mass of vibrating bees.
The Hornet and the
Japanese Diet
In Japan's mountain villages, the hornets are valued as part of the
basic diet. They are eaten deep fried or as a kind of hornet
sashimi.
Hornet supplement
manufacturers
Recently several companies in Asia and Europe have begun to
manufacture dietary supplements and energy drinks supposedly
containing the secretions of the larvae of Vespa Mandarina Japonica, which the
adult hornets usually consume. According to the manufacturers of
these products, because the adult hornet can fly 50 miles in a
single day at 20 miles per hour, consuming the larval hornet
secretions (marketed as "hornet juice") will similarly enhance
human endurance.
Note that these "supplements" are not really made from hornets, but
synthesized from, eg, according to Vaam: "Diet Amino is composed
of: Maltodextrin, Betacarotene, Amino Acids (Proline, Lysine,
Leucine,Valine, Isoleucine, Alanine), Vitamin E, Vitamin B1,
Flavoring, Acidifier, Sweetener (Stevia, Sucrose)". Also that there
is no medical evidence that these have any effect, but as
"supplements" rather than pharmaceuticals, do not have to prove
their claims.
Issue #161
