The actaeon beetle (''Megasoma actaeon'') is a

rhinoceros beetle Dynastinae or rhinoceros beetles are a subfamily of the scarabaeidae, scarab beetle family (biology), family (Scarabaeidae). Other common names – some for particular groups of rhinoceros beetles – include Hercules beetles, unicorn be ...

of the family

Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 35,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change. Several groups formerly tre ...

Etymology

The species name ''actaeon'' derives from the name

Actaeon In Greek mythology, Actaeon (; ''Aktaiōn'') was the son of the priestly herdsman Aristaeus and Autonoe in Boeotia, and a famous Thebes, Greece, Theban Greek hero cult, hero. Through his mother he was a member of the ruling House of Cadmus. Like ...

of a famous Theban hero, son of the priestly herdsman

Aristaeus Aristaeus (; ''Aristaios'') was the mythological culture hero credited with the discovery of many rural useful arts and handicrafts, including bee-keeping; He was the son of the huntress Cyrene and Apollo. ''Aristaeus'' ("the best") was a cu ...

and Autonoe in

Boeotia Boeotia ( ), sometimes Latinisation of names, Latinized as Boiotia or Beotia (; modern Greek, modern: ; ancient Greek, ancient: ), is one of the regional units of Greece. It is part of the modern regions of Greece, region of Central Greece (adm ...

, trained by the centaur

Chiron In Greek mythology, Chiron ( ; also Cheiron or Kheiron; ) was held to be the superlative centaur amongst his brethren since he was called the "wisest and justest of all the centaurs". Biography Chiron was notable throughout Greek mythology for ...

Description

Actaeon beetle is one of the largest of all

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s, measuring up to across, with a body length of about . The males can grow to be long by thick . The dorsal surfaces are glabrous (bald), matte or shiny black. The legs are powerful, with large tarsal claws. Males have appendages resembling horns on the

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

and on the head. The two parallel horns on the

are short, acute and forward pointing, while a much longer horn with a small tooth is present on the head. In the females the

and the

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

are rugose and the horns are missing.

Life cycle

Females lay eggs into soil at

eclosion A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

and eggs develop in about 9 months. Larval development and

pupation A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

takes in total almost 3 years. Larvae at the 3rd

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

can reach the weight of 200 grams, the highest weight among insects. Life expectancy of adults in captivity reaches about 100–150 days. The heaviest ''actaeon'' larva ever recorded was found in the northern regions of South America weighed in 2009 nearly equivalent to a female rat. Adults are much less massive, with no confirmed specimens exceeding the record-holder among insects, the Little Barrier giant weta, '' Deinacrida heteracantha'', documented to attain up to 71g.Richards, A.O. 1973. A comparative study of the biology of the giant wetas ''Deinacrida heteracantha'' and ''D. fallai'' (Orthoptera: Henicidae) from New Zealand. Journal of Zoology 169: 195-236Book of Insect Records: Largest
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Distribution

This species can be found in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

, particularly in

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

, and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

References

Photos Elephant beetle ''Megasoma actaeon''

External links