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

rhinoceros beetle Dynastinae or rhinoceros beetles are a subfamily of the scarab beetle family (Scarabaeidae). Other common names – some for particular groups of rhinoceros beetles – include Hercules beetles, unicorn beetles or horn beetles. Over 1 ...

of the family

Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...

Etymology

The species name ''actaeon'' derives from the name Actaeon of a famous Theban hero, son of the priestly herdsman

Aristaeus A minor god in Greek mythology, attested mainly by Athenian writers, Aristaeus (; ''Aristaios'' (Aristaîos); lit. “Most Excellent, Most Useful”), was the culture hero credited with the discovery of many useful arts, including bee-keepin ...

and Autonoe in

Boeotia Boeotia ( ), sometimes Latinized as Boiotia or Beotia ( el, Βοιωτία; modern: ; ancient: ), formerly known as Cadmeis, is one of the regional units of Greece. It is part of the region of Central Greece. Its capital is Livadeia, and its ...

, 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 ...

Description

Actaeon beetle is one of the largest of all

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s, measuring up to across, with a body length of about . The males can grow to be 13 cm (5.4 in) long by 4 cm (1.6 in) 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 (; ; , ) 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 (sometimes alterna ...

are rugose and the horns are missing.

Life cycle

Females lay eggs into soil at

eclosion A pupa ( la, pupa, "doll"; plural: ''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 ...

and eggs develop in about 9 months. Larval development and

pupation A pupa ( la, pupa, "doll"; plural: ''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 thei ...

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, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

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 ever recorded was found in the northern regions of South America weighed 228 grams (8.04 oz) in 2009 nearly equivalent to a female rat. This not only makes it the heaviest beetle but the heaviest insect of any kind.

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 relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

, particularly in Bolivia,

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, Colombia,

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...

México Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatem ...

French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas department/region and single territorial collectivity of France on the northern Atlantic coast of South America in the Guianas. ...

, Guyana,

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...

, Suriname, and

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

References

Photos Elephant beetle ''Megasoma actaeon''

External links