Japanese rhinoceros beetle

Japanese rhinoceros beetle
File:Kabutomushi-JapaneseBeetle-July2004.jpg
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Family:	Scarabaeidae
Subfamily:	Dynastinae
Genus:	Allomyrina Arrow, 1911
Species:	A. dichotoma
Binomial name
Allomyrina dichotoma (Linnaeus, 1771)
Synonyms
Trypoxylus dichotomus Allomyrina dichotomus

The Japanese rhinoceros beetle, Japanese horned beetle, or kabutomushi (カブトムシ), Allomyrina dichotoma, is a species of rhinoceros beetle.

Etymology

In Japanese, rhinoceros beetles are called kabutomushi (かぶとむし, also written 甲虫 or かぶと虫). Mushi is Japanese for bug, and kabuto is Japanese for helmet. So, literally, it means helmet-bug referring to a samurai helmet.

List of subspecies

• Allomyrina dichotoma dichotoma
• Allomyrina dichotoma inchachina
• Allomyrina dichotoma septentrionalis
• Allomyrina dichotoma takarai
• Allomyrina dichotoma tunobosonis

Description

Allomyrina dichotoma, male and female. Mounted specimen

Allomyrina dichotoma shows a striking sexual dimorphism. The males are much larger, reaching a length of 40–80 mm, while females can reach a length of about 40–60 mm. The long cephalic horn of this species has a characteristic shape in the form of the letter Y and it is used by males during the mating period and to maintain territories. By means of their forked horn they lift other males off the ground and throw them into the air. In addition to their impressive and ornate protuberance they also have a smaller thoracic horn, also forked. Their eyes may be white or red and are adapted to low light levels, as this species is nocturnal. The body is dark brown, while the ventral part of the body is black, brilliant and the front legs are unusually long. Like all Dynastinae species, these beetles are strong flyers, although they never cover long distances during the flight. The preferred foods are tree saps, fruits and anything sugary.

Distribution and habitat

This species is present in Japan (Hondo and Kyūshū), Taiwan, Korea and eastern China. It can be found in broad-leaved forests in tropical and subtropical mountainous habitats.

Lifespan

File:Allomyrina dichotoma L3 Larva.JPG

Third instar Larva (last step before metamorphosis)

The Japanese rhinoceros beetle will live most of its life underground, for it only lives about four months as an actual beetle. The earliest beetles will come out of the ground in late spring; they will usually die around middle September to early October. They usually will die after mating and laying eggs.

The eggs are laid directly in the ground, then hatch into a wriggling larva, which usually mature in a year. But life as an adult is short; in less than 4 months he must find and defend a territory and win over the fairer sex. To do this he must fight. Male beetles normally die in the fall after mating many times, whereas female beetles normally die after laying eggs.

Japanese scientists are trying to find supplements to make the Japanese rhinoceros beetle mature faster and grow to a larger size. Disturbing the beetle during its pupal stage is known to cause deformations in the beetle's physiology and possibly cause the beetle to die of shock. Touching the Japanese rhinoceros beetle too suddenly, even after it has metamorphosed, may also cause the beetle to die of shock.

In Japanese culture

File:Kabutomushi-20070710.jpg

Japanese rhinoceros beetle

Many children in Japan buy or catch these beetles and breed them, some for insect fighting. Male and female insects cost about 500 to 1000 yen in department stores.

In the most popular form of beetle fighting, called "kabutomushi sumo" (カブトムシ相撲), two different male beetles are placed on a log to try to push each other off the log or flip the other over. Some fights are even a subject of gambling.

The Japanese rhinoceros beetle is also a popular subject in origami, the ancient art of paper folding. Almost every major origami designer has made a rendition of this beetle.

Bibliography

• Y. Hongo Does flight ability differ among male morphs of the Japanese horned beetle Trypoxylus dichotomus septentrionalis (Coleoptera Scarabaeidae)? Ethology Ecology & Evolution - Volume 22, Issue 3, 2010
• Yoshihito Hongo Behaviour During Male-male Interaction in the Japanese Horned Beetle Trypoxylus Dichotomus Septentrionalis (Kono) Behaviour, Volume 140, Issue 4
• YUTAKA IGUCHI Intrasexual fighting and mounting by females of the horned beetle Eur. J. Entomol. 107: 61–64, 2010
• Van Truong T, Byun D, Lavine LC, Emlen DJ, Park HC, Kim MJ. Flight behavior of the rhinoceros beetle Trypoxylus dichotomus during electrical nerve stimulation.

External links

• Photos of Allomyrina dichotoma septentrionalis
• Photos of Allomyrina dichotoma tunobosonis
• Photos of Allomyrina dichotoma