Moellenkampi beetle

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Moellenkampi beetle
Three-horned rhinoceros beetle (Chalcosoma moellenkampi) male.jpg
Male
Three-horned rhinoceros beetle (Chalcosoma moellenkampi) female.jpg
Female
both Sabah, Borneo
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Scarabaeidae
Genus: Chalcosoma
Species:
C. moellenkampi
Binomial name
Chalcosoma moellenkampi
Kolbe, 1900

The Moellenkampi beetle (Chalcosoma moellenkampi), is one of four large species of rhinoceros beetles from Southeast Asia belonging to the genus Chalcosoma . [1] 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. [2]

Contents

Distribution

Unlike its close relatives, C. atlas, C. chiron, and C. engganensis, C. moellenkampi has a rather restricted geographic distribution and appears to occur only on Borneo. [1]

Description

Chalcosoma moellenkampi can reach about the same size as C. atlas, and males may measure up to 110 mm (4.3 in) from the tip of the head horn to the end of the elytra (wingcases). The largest species in the genus is Chalcosoma chiron, where males may occasionally reach 130 mm (5.1 in). [3] Females are much smaller than males, usually only 45–60 mm (1.8–2.4 in), and lack horns. Unlike the males, which in Chalcosoma can be distinguished from each other using the characteristics listed below, females are very similar in the three Chalcosoma species, and can usually only be distinguished from each other by specialists.

Atlas beetle males are renowned for their three horns, two on the pronotum and one on the head. Owing to environmental conditions, not all larvae grow to similar sizes, and those that live in harsher conditions, adult beetles become small. In small males, the horns are very short and the head horn extends almost vertically upwards and usually has three small prongs, but in large males, the horns are enormous, and the head horn projects mainly anteriorly with an upwards curvature. The size of the horns relative to the size of the beetle is thus positively allometric, meaning the horns are much larger relative to the body size of the beetle in large males compared to small males, which have very short horns. [4] In contrast, females do not show such dramatic differences in body proportions, and large females are simply larger versions of small females. [4]

Behavior

Male showing wings Chalcosoma sp. (13476779694).jpg
Male showing wings

As the other species of Atlas beetles, large males in C. moellenkampi are very aggressive towards other males, but small males are more peaceful, lacking the body size and large horns to fight. Unlike the great differences in horn size at different body sizes, the size of the male genitalia, known as parameres, do not vary nearly as much in large and small males, implying males of all sizes can still mate with females. [5] In the wild, the Chalcosoma species live in rainforests and palm plantations, [2] and males and females typically meet at feeding sites, for instance wounded trees, where the beetles drink the sap. They reach new areas by flying around at night. At the feeding sites, large males attempt to dominate the site by sheer size, and chase smaller males away. The dominance ensures the big males' mating rights with any females that come to the site. However, if two equally large males meet, neither is usually prepared to back away and they fight each other using their large horns, while also trying to trip the opponent with their long front legs. A male tries to pin a rival between the head horn—which it can move upwards or downwards as it raises or lowers its head—and the two pronotum horns. The beetle then tries to throw its rival off the branch, or throw it on its back.

In other beetles where only large males have big horns and are aggressive, small males rely on stealth, avoiding physical confrontation with the large males, and instead try to mate with females while the large males are busy fighting each other. [6] While such behavior has not been reported from the wild for C. moellenkampi, it is known for C. atlas and it is probably present in C. moellenkampi, as well, since the two species are closely related and very similar in other life history aspects.

This violent temper also means that in captivity, males cannot be in the same vivarium, as they engage in violent fights that could cause physical injury. The species is less common among beetle hobbyists than C. atlas, and the breeding ecology is therefore less well known in C. moellenkampi, but C. atlas larvae are unusual among rhinoceros beetles by being quite aggressive and willing to bite if touched, and larvae of C. moellenkampi may share this behavior. Females burrow into the soil or into old rotting hardwood logs to lay eggs. The larvae go through three stages of development, and may reach a massive weight of 100 g. At the end of larval stage 3, the larva creates a large, oval cocoon of decayed wood and earth, where it transforms into a pupa, which hatches out in another two months. The total generation span from egg to adult beetle may take 13–18 months. [2]

Related Research Articles

<span class="mw-page-title-main">Scarabaeidae</span> Family of beetles

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 subfamilies have been elevated to family rank, and some reduced to lower ranks. The subfamilies listed in this article are in accordance with those in Bouchard (2011).

<span class="mw-page-title-main">Hercules beetle</span> Species of beetle

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.

<span class="mw-page-title-main">Dynastinae</span> Subfamily of beetles

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 1500 species and 225 genera of rhinoceros beetles are known.

<i>Dynastes tityus</i> Species of beetle

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.

<span class="mw-page-title-main">Japanese rhinoceros beetle</span> Species of beetle

Allomyrina dichotoma, also known as Japanese rhinoceros beetle, Japanese horned beetle, or kabutomushi, is a species of rhinoceros beetle.

<span class="mw-page-title-main">Atlas beetle</span> Species of beetle

The Atlas beetle is a very large species of beetle in the family Scarabaeidae, found in Southeast Asia. Males have three prominent horns. The species is named for Atlas, the giant of Greek mythology who supported the skies.

<span class="mw-page-title-main">Elephant beetle</span> Species of beetle

The elephant beetle is a member of the family Scarabaeidae and the subfamily Dynastinae. They are Neotropical rhinoceros beetles.

<i>Goliathus regius</i> Species of beetle

Goliathus regius, the Royal Goliath beetle, is a species of beetles of the family Scarabaeidae.

<span class="mw-page-title-main">Actaeon beetle</span> Species of beetle

Actaeon beetle is a rhinoceros beetle of the family Scarabaeidae.

<span class="mw-page-title-main">European rhinoceros beetle</span> Species of beetle

The European rhinoceros beetle is a large flying beetle belonging to the subfamily Dynastinae.

<i>Xylotrupes gideon</i> Species of beetle

Xylotrupes gideon, the brown rhinoceros beetle, is a species of large scarab beetle belonging to the subfamily Dynastinae.

<i>Dynastes satanas</i> Species of beetle

Dynastes satanas, the Satanas beetle, is a species of beetle belonging to the family Scarabaeidae. The name is sometimes misspelled as "satanus".

<i>Megasoma</i> Genus of beetles

Megasoma is a genus of rhinoceros beetles. Commonly known as the elephant beetles, Megasoma species are found from the southern half of North America to most of South America.

<i>Chalcosoma</i> Genus of beetles

Chalcosoma is a genus of Southeast Asian rhinoceros beetles. They are known as three horned rhinoceros beetles for their trident like horn. They are endemic to Southeast Asia.

<i>Chalcosoma chiron</i> Species of beetle

Chalcosoma chiron is a species of beetle in the family Scarabaeidae. This species can be found from Malaysia south into Indonesia and Thailand in East region. It was formerly known as Chalcosoma caucasus, a name which is a junior synonym and not valid.

Chalcosoma engganensis is a large (35–60 mm) and heavy beetle. The body is shiny black. The male has a sharp horn on the head. On each side of pronotum there are curved, forward directed horns. Across the head there is a short but powerful spike. This species differs from the normally developed specimens of the other Chalcosoma species in that horns are shorter, male can look a lot like small copies of Chalcosoma moellenkampi. The female lacks these horns and spikes, and is smaller.

<i>Golofa imperialis</i> Species of beetle

Golofa imperialis is a species of rhinoceros beetles belonging to the family Scarabaeidae.

<i>Xylotrupes socrates</i> Species of beetle

Xylotrupes socrates, commonly known as the Siamese rhinoceros beetle or fighting beetle, is a species of large scarab beetle belonging to the subfamily Dynastinae. It is particularly known for its role in insect fighting in Thailand.

Cyclocephala latericia is a beetle which belongs to the subfamily Dynastinae in the family Scarabaeidae.

<i>Oryctes gnu</i> Species of beetle

Oryctes gnu, commonly known as Malaysian rhinoceros beetle, is a species of dung beetle native to South Asian and South East Asian countries including: India, Pakistan, Sri Lanka, Philippines, Thailand, Philippines, and Vietnam. It is also introduced to many parts of the world.

References

  1. 1 2 Endrödi, S. (1985). The Dynastinae of the World. Dordrecht: Springer-Verlag. ISBN   906193138X.
  2. 1 2 3 Löwenberg, A. (1999). Exotische Käfer. Pflege und Zucht von Rosen- und Riesenkäfern im Terrarium. Ruhmannsfelden: bede-Verlag. ISBN   3-933 646-44-8.
  3. ↑ Mizunuma, T. (1999). Giant beetles. Euchiridae, Dynastinae. Tokyo: Toshitsugu Endo.
  4. 1 2 Kawano, K. (1995). "Horn and wing allometry and male dimorphism in giant rhinoceros beetles (Coleoptera: Scarabaeidae) of tropical Asia and America". Ann. Entomol. Soc. Am. 88 (1): 92–99. doi:10.1093/aesa/88.1.92.
  5. ↑ Kawano, K. (2004). "Developmental stability and adaptive variability of male genitalia in sexually dimorphic beetles" (PDF). Am. Nat. 163 (1): 1–15. doi:10.1086/379796. PMID   14767832.
  6. ↑ Emlen, D.J. & Nijhout, H.F. (2000), "The development and evolution of exaggerated morphologies in insects" (PDF), Annu. Rev. Entomol., 45: 661–708, doi:10.1146/annurev.ento.45.1.661, PMID   10761593

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