Dynastinae or rhinoceros beetles are a subfamily of the scarab beetlefamily (Scarabaeidae). Other common names – some for particular groups of rhinoceros beetles – include Hercules beetles, unicorn beetles or horn beetles. Over 1,500 species and 225 genera of rhinoceros beetles are known.[2]
The Dynastinae are among the largest of beetles, reaching more than 15 centimetres (6 inches) in length, but are completely harmless to humans because they cannot bite or sting. Some species have been anecdotally claimed to lift up to 850 times their own weight.[3] An extinct EoceneOryctoantiquus borealis was the largest fossil scarabeid, with a length of 5 centimetres (2.0in).[4] Some modern Oryctini grew up to 7cm (3in).[4] Common names of the Dynastinae refer to the characteristic horns borne only by the males of most species in the group. Each has a horn on the head and another horn pointing forward from the center of the thorax. The horns are used in fighting other males during mating season, and for digging. The size of the horn is a good indicator of nutrition and physical health.[5]
The body of an adult rhinoceros beetle is covered by a thick exoskeleton. A pair of thick wings lie atop another set of membranous wings underneath, allowing the rhinoceros beetle to fly, although not very efficiently owing to its large size. Their best protection from predators is their size and stature, also avoiding many due to being nocturnal. When the sun is out, they hide under logs or in vegetation to camouflage themselves from the few predators big enough to eat them. If rhinoceros beetles are disturbed, some can release very loud, hissing squeaks created by rubbing their abdomens against the ends of their wing covers.
Ecology
These beetles' larval stages can be several years long. The larvae feed on rotten wood and the adults feed on nectar, plant sap, and fruit. First, the larvae hatch from eggs and later develop into pupae before they reach adulthood. The females lay 50 eggs on average. Contrary to what their size may imply, adult rhinoceros beetles do not eat large amounts, unlike their larvae, which eat a significant amount of rotting wood.[citation needed] Rhinoceros beetles are relatively resilient; a healthy adult male can live up to 2–3 years. The females rarely live long after they mate.[citation needed]
Mating
Male Japanese rhinoceros beetles (Allomyrina dichotoma) fight to dominate sap sites. Males use their horns to pry rival males off the area, which also may give them the chance to mate with a female. In this and other species that defend mating sites, larger males with larger horns mate more frequently, as they win more contests. Small males often avoid larger males and exhibit alternative strategies to gain access to females.[6][7]
As pests
Some species, such as the coconut rhinoceros beetle (Oryctes rhinoceros), can become major pests, e.g., in tree plantations.[8] Usually though, beetle population densities are not as high as in some other pest insects, and they typically prefer food trees which are already sick or dying from some other cause. Some species' larvae, however, will attack healthy trees or even root vegetables, and when they occur in large numbers, can cause economically significant damage. The fungus Metarhizium majus is a proven biocontrol agent for beetle infestation in crops.
Uses
Rhinoceros beetles have become popular pets in parts of Asia,[9] due to being relatively clean, easy to maintain, and safe to handle. Also in Asia, male beetles are used for gambling fights.[10] Since males naturally have the tendency to fight each other for the attention of females, they are the ones used for battle. To get the two male beetles to lock in combat, a female beetle is used, or a small noisemaker duplicating the female's mating call.
Dr. MinJun Kim, leading a team of engineers in National Science Foundation-funded research, examined the function and aerodynamics of Allomyrina dichotoma with the help of researchers in Drexel University's Mechanical Engineering Department and in collaboration with Konkuk University in South Korea. Rhinoceros beetles could play a big part in the next generation of aircraft design.[12]
↑ Bouchard, P., Y. Bousquet, A. Davies, M. Alonso-Zarazaga, J. Lawrence, C. Lyal, A. Newton, et al. (2011). "Family-group names in Coleoptera (Insecta)". ZooKeys, vol. 88, 1-972.
↑ Beutel, Rolf G.; Leschen, Richard A.B., eds. (2016-03-21). Coleoptera, Beetles, Volume 1, Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim). De Gruyter. doi:10.1515/9783110373929. ISBN978-3-11-037392-9.
↑ Goczał, Jakub; Rossa, Robert; Tofilski, Adam (17 April 2019). "Intersexual and intrasexual patterns of horn size and shape variation in the European rhinoceros beetle: quantifying the shape of weapons". Biological Journal of the Linnean Society. 127 (1): 34–43. doi:10.1093/biolinnean/blz026.
The Hercules beetle is a species of rhinoceros beetle native to the rainforests of southern Mexico, Central America, South America, and the Lesser Antilles. It is the longest extant species of beetle in the world, and is also one of the largest flying insects in the world.
Dynastes tityus, the eastern Hercules beetle, is a species of rhinoceros beetle native to the Eastern United States. The adult's elytra are green, gray or tan, with black markings, and the whole animal, including the male's horns, may reach 60 mm (2.4 in) in length. The larvae feed on decaying wood from various trees.
Allomyrina dichotoma, also known as the Japanese rhinoceros beetle, Japanese horned beetle, or kabutomushi, is a species of rhinoceros beetle. They are commonly found in continental Asia in countries such as China, the Korean peninsula, Japan, and Taiwan. In these areas, this species of beetle is often found in broad-leaved forests with tropical or sub-tropical climates. This beetle is well known for the prominent cephalic horn found on males. Male Japanese rhinoceros beetles will use this horn to fight other males for territory and access to female mating partners. Upon contact, males will attempt to flip each other onto their backs or off of their feeding tree. In response to selective pressures, smaller male A. dichotoma have adapted a "sneak-like behavior". These smaller beetles will attempt to avoid physical confrontation with larger males and try to mate with females.
Dynastes is a genus of large beetles belonging to the family Scarabaeidae. They occur in the Nearctic realm and in the Neotropical realm, from the United States to Brazil; four North American species, three with distributions extending from Central America either north or south, and two species endemic to South America.
The elephant beetle is a member of the family Scarabaeidae and the subfamily Dynastinae. Elephant beetles are Neotropical rhinoceros beetles.
Tomarus is a genus of scarab beetles in the subfamily Dynastinae, the rhinoceros beetles. They are native to the Americas, where they are distributed from the central United States to Argentina, and a few species occur in the Caribbean.
The European rhinoceros beetle is a large flying beetle belonging to the subfamily Dynastinae.
Xylotrupes ulysses, common names "Elephant beetle", "Coconut palm beetle", "common rhinoceros beetle" or simply "rhinoceros beetle" is a species of rhinoceros beetle native to New Guinea. Male horns in several groups of this genus represent a special secondary sex characteristic. There is a bimodal horn-size distribution and there is a discrete male mating behavior correlated with each phenotype.
Xylotrupes gideon, the brown rhinoceros beetle, is a species of large scarab beetle belonging to the subfamily Dynastinae.
The western Hercules beetle is a species of rhinoceros beetle that lives in Arizona, New Mexico and Utah in the United States and in parts of northern Mexico. This species is known for its grayish-white elytra, large size, and characteristic horn of the adult males.
Oryctes rhinoceros is a large beetle, belonging to the rhinoceros beetles, subfamily Dynastinae, of the family Scarabaeidae. Its vernacular names include coconut rhinoceros beetle, Asiatic rhinoceros beetle, and coconut palm rhinoceros beetle. O. rhinoceros attacks coconut palms and other palms like the economically important oil palm. It can cause serious damage to the developing fronds (leaves) up to death of the palm. The beetle breeds in decaying palm trunks or other organic matter like sawdust or compost heaps.
Megasoma gyas is a species of large Neotropical rhinoceros beetles. There are no recognized subspecies.
Oryctes is the most economically important genus of rhinoceros beetles in the subfamily Dynastinae, since it includes a notorious insect pest of palms.
The Moellenkampi beetle, is one of four large species of rhinoceros beetles from Southeast Asia belonging to the genus Chalcosoma. The Moellenkampi beetles belong to the beetle family Scarabaeidae along with other rhinoceros beetles. They are characterized by having two large, forward-projecting horns on the pronotum or thorax, and another large, forward and upward-projecting horn on the head. They also have a distinct metallic lustre, which is the reason behind their genus name, which derives from Greek, chalko-, and is the combining form of chalkós, meaning copper.
Pentodontini is a tribe of rhinoceros beetles in the family Scarabaeidae. There are over 100 genera in the tribe Pentodontini.
Hemiphileurus is a genus of rhinoceros beetles in the family Scarabaeidae. There are at least 60 described species in Hemiphileurus.
Phileurus is a genus of rhinoceros beetles in the family Scarabaeidae. There are more than 20 described species in Phileurus.
Oryctini is a tribe of beetles in the Dynastinae.
Dynastini is a tribe of rhinoceros beetles in the family Scarabaeidae.
Dynastes neptunus is a beetle in the family Scarabaeidae. D. neptunus is very similar to the Hercules beetle but differs from it in slightly larger size and more of a slender and curved horns.
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