Hercules beetle

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Hercules beetle
Dynastes hercules ecuatorianus MHNT.jpg
Male Hercules beetle, Dynastes hercules ecuatorianus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Scarabaeidae
Genus: Dynastes
Species:
D. hercules
Binomial name
Dynastes hercules
Synonyms
  • Scarabaeus hercules Linnaeus, 1758, 1758
  • Scarabaeus scaber Linnaeus, 1758, 1764
  • Scarabaeus oculatus Scopoli, 1772
  • Scarabaeus alcides Fabricius, 1781
  • Scarabaeus iphiclus Panzer, 1782
  • Scarabaeus perseus Olivier, 1789
  • Dynastes alcides(Fabricius, 1781)
  • Dynastes lagaii Verrill, 1906
  • Dynastes vulcan Verrill, 1906
  • Dynastes argentata Verrill, 1907
  • Dynastes hercules nigerEndrodi, 1947
  • Dynastes hercules caribaeaStehle & Stehle, 1958
  • Dynastes hercules baudriiPinchon, 1976

The Hercules beetle (Dynastes hercules) 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.

Contents

Etymology

Dynastes hercules is known for its tremendous strength and is named after Hercules, a hero of classical mythology who is famed for his great strength.

Taxonomy

D. hercules has a complex taxonomic history and has been known by several synonyms. It is in the subfamily Dynastinae (rhinoceros beetles) in the larger family Scarabaeidae (commonly known as scarab beetles). Not counting subspecies of D. hercules, seven other species are recognized in the genus Dynastes .

Subspecies

Several subspecies of D. hercules have been named, [1] [2] though still some uncertainty exists as to the validity of the named taxa. [3] [4]

Description

Adult body sizes (not including the thoracic horn) vary between 50 and 85 mm (2.0 and 3.3 in) in length and 29 and 42 mm (1.1 and 1.7 in) in width. [5] Male Hercules beetles may reach up to 173 mm (7 in) in length (including the horn), making them the longest species of beetle in the world, if jaws and/or horns are included in the measurement. [3] [6] The size of the horn is naturally variable, more so than any variation of the size of legs, wings, or overall body size in the species. This variability results from developmental mechanisms that coincide with genetic predisposition in relation to nutrition, stress, exposure to parasites, and/or physiological conditions. [7]

Dynastes hercules is highly sexually dimorphic, with only males exhibiting the characteristic horns (one on the head, and a much larger one on the prothorax). [8] The body of males is black with the exception of the elytra, which can have shades of olive-green. They have a black suture with sparsely distributed black spots elsewhere on the elytra. [5] They have a slightly iridescent coloration to their elytra, which varies in color between specimens and may be affected by the humidity of the local environment in which they develop. [9] [10] At low humidity the elytra are olive-green or yellow in color, but darken to black at higher humidity due to its hygrochromic properties. [9] [11]

Females of D. hercules have punctured elytra which are usually entirely black, but sometimes have the last quarter of the elytra colored in the same way as the males. [5]

Distribution and habitat

Populations of D. hercules may be found from southern Mexico to Bolivia in mountainous and lowland rain forests. Known populations include the Lesser Antilles, Trinidad and Tobago, Brazil, Ecuador, Colombia, and Peru. [5] Chromosomal analysis has shown that the genus Dynastes originated from South America. [12]

Life cycle

The Larva of D. hercules is amongst the largest in any insect. Hercules beetle (larva).jpg
The Larva of D. hercules is amongst the largest in any insect.

Not much is known about the life cycle in the wild, but much evidence has been gained through observations of captive-bred populations. [5] The mating season for adults typically occurs during the rainy season (July to December). Females have an average gestation period of 30 days from copulation to egg-laying, and may lay up to 100 eggs on the ground or on dead wood. The eggs have an incubation period of approximately 27.7 days before they hatch. [11] Once hatched, the larval stage of the Hercules beetle may last up to two years in duration, where it will go through 3 metamorphosis stages, also known as instars. [5] The larvae have a yellow body with a black head. The larvae can grow up to 11 cm (4.5 in) in length and weigh more than 100 grams. [11] In laboratory conditions at 25 ± 1°C, the first instar stage lasts an average of 50 days, the second stage an average of 56 days, and the third an average of 450 days. After the third instar stage, the pupal stage lasts about 32 days, where it will transition into an adult. Adult beetles can live for three to six months in captivity. [5]

Diet and behavior

Diet

The larvae of the Hercules beetle are saproxylophagous, meaning that they feed on rotting wood; they reside in same during their two-year developmental stage. [5] [9] The adult Hercules beetle feeds on fresh and rotting fruit, along with tree sap. [9] [10] [13] Adults carve bark through the use of its synchronous mandibles to easily access the sap of trees. When these mandibles are closed, a narrow opening is formed which can act like a straw to allow consumption of tree sap. [13] They have been observed feeding on peaches, pears, apples, grapes, bananas, and mangoes in captivity. [10] [14] [15]

Behavior

Within their native rain forest habitats, the adult beetles, which are nocturnal, forage for fruit at night and hide or burrow within the leaf litter during the day. [11] The adult D. hercules beetles are capable of creating a 'huffing' sound, generated by stridulating their abdomen against their elytra to serve as a warning to predators. [11] [16] Like most insects, communication within the species is a mix of chemoreception, sight, and mechanical perception. Experiments on D. hercules have shown that a male placed in the vicinity of a female will immediately orient towards her and seek her out, suggesting chemical communication through strong sexual pheromones. [16]

Combat behavior between males

It has been observed in wild habitat and in captivity that male D. hercules will engage in combat to win possession and mating rights to a female. [17] Male Hercules beetles typically use their large horns to settle mating disputes; these fights can cause significant physical damage to the combatants but may also include possible damage to the female in the process. [18] During fights, the males attempt to grab and pin their rival between the cephalic and thoracic horns to lift and throw them. The successful male wins mating rights with the female, though the beetles remain polygynandrous. [11]

Physical strength

Reports suggest the Hercules beetle is able to carry up to 850 times its body mass. Actual measurements on a much smaller (and relatively stronger: see square-cube law) species of rhinoceros beetle shows a carrying capacity only up to 100 times their body mass, at which point they can barely move. [19]

Relationship to humans

Dynastes hercules does not negatively affect human activities, either as an agricultural pest or disease vector. The beetles can be kept as pets. [11] Larvae excrement has been shown to contain β-mannanase, a bacterially synthesized enzyme that hydrolyzes hemicellulose that can be used in enzyme based cleaning products. β-mannanase has been successfully extracted and cloned from larvae fecal matter, suggesting that production of bio additive cleaning products may be feasible. [20]

Relationship to the environment

Dynastes hercules is a beneficial contributor to the rain forest ecosystem, primarily during their larval stage where they are saproxylophagous. Feeding on rotting wood assists with biodegradation and cycling nutrients in the environment. [5]

See also

Related Research Articles

<span class="mw-page-title-main">Beetle</span> Order of insects

Beetles are insects that form the 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 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.

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

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 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 Catalog of Life (2023).

<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">Titan beetle</span> Genus of beetles

The titan beetle is a Neotropical longhorn beetle, the sole species in the genus Titanus, and one of the largest known beetles.

<i>Goliathus</i> Genus of beetles

The Goliath beetles are any of the five species in the genus Goliathus. Goliath beetles are among the largest insects on Earth, if measured in terms of size, bulk and weight. They are members of subfamily Cetoniinae, within the family Scarabaeidae. Goliath beetles can be found in many of Africa's tropical forests, where they feed primarily on tree sap and fruit. Little appears to be known of the larval cycle in the wild, but in captivity, Goliathus beetles have been successfully reared from egg to adult using protein-rich foods such as commercial cat and dog food. Goliath beetles measure from 60–110 millimetres (2.4–4.3 in) for males and 50–80 millimetres (2.0–3.1 in) for females, as adults, and can reach weights of up to 80–100 grams (2.8–3.5 oz) in the larval stage, though the adults are only about half this weight. The females range from a dark chestnut brown to silky white, but the males are normally brown/white/black or black/white.

<i>Macrodontia cervicornis</i> Species of beetle

Macrodontia cervicornis, also known as the sabertooth longhorn beetle, is one of the largest beetles, if one allows for the enormous mandibles of the males, from which it derives both of the names in its binomen: Macrodontia means "long tooth", and cervicornis means "deer antler". Measurements of insect length normally exclude legs, jaws, or horns, but if jaws are included, the longest known specimen of M. cervicornis is 17.7 cm; the longest known specimen of Dynastes hercules, a beetle species with enormous horns, is 17.5 cm, and the longest known beetle excluding either jaws or horns is Titanus giganteus, at 16.7 cm.

<i>Dynastes</i> Genus of beetles

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.

<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. Elephant beetles are Neotropical rhinoceros beetles.

<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>Dynastes grantii</i> Species of beetle

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.

<i>Inca clathratus</i> Species of beetle

Inca clathratus is a species of flower chafer in the family Scarabaeidae, indigenous to Central and South America. These beetles can be seen surrounding the sap flows from injured or diseased trees anytime in the day and sometimes at night. They mostly feed at the sap flows of the trees, including avocado and mango trees. Like other beetles they also feed off of rotting fruit. There are a few different subspecies of Inca clathratus including: Inca clathratus sommeri, Inca clathratus clathratus, and Inca clathratus quesneli. The species name has been frequently misspelled as "clathrata" but the genus name Inca is masculine.

Xylotrupes meridionalis, commonly known as forked horns rhinoceros beetle, is a species of rhinoceros beetle found in India and Sri Lanka.

<i>Dynastes neptunus</i> Species of insect

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.

Dynastes maya, the Maya white beetle, is a species of New World scarab beetles (Scarabaeidae). It has a distribution range in the Central American region, specifically in southern Mexico, Honduras, and Guatemala.

References

  1. ↑ "Hercules Beetle, Dynastes hercules". BioLib.cz. 2017. Archived from the original on 2018-12-06. Retrieved 2017-07-09.
  2. ↑ Huang, J.P. (15 September 2017). "The Hercules beetles (subgenus Dynastes, genus Dynastes, dynastidae) A revisionary study based on the integration of molecular, morphological, ecological, and geographic analyses". Miscellaneous Publications, Museum of Zoology, University of Michigan. 206: 1–32 – via ResearchGate.
  3. 1 2 Ratcliffe, B.C.; Cave, R.D. (2015). "The dynastine scarab beetles of the West Indies (Coleoptera: Scarabaeidae: Dynastinae)". Bulletin of the University of Nebraska State Museum. 28: l–346.
  4. ↑ Huang, J., Knowles, L. The species versus subspecies conundrum: quantitative delimitation from integrating multiple data types within a single bayesian approach in Hercules beetles. Systematic Biology, vol. 65, 2015, 15p.
  5. 1 2 3 4 5 6 7 8 9 Keller, O.; Cave, R. D. Cave (2016). "Hercules Beetle Dynastes hercules (Linnaeus, 1758) (Insecta: Coleoptera: Scarabaeidae)" (PDF). University of Florida, IFAS Extension. Archived (PDF) from the original on 2017-08-29. Retrieved 2017-05-20.
  6. ↑ "Largest species of beetle". Guinness World Records. Archived from the original on 2017-05-09. Retrieved 2017-05-20.
  7. ↑ Lavine, L.; Gotoh, H.; Brent, C. S.; Dworkin, I.; Emlen, D. J. (2015). "Exaggerated Trait Growth in Insects". Annual Review of Entomology. 60: 453–472. doi: 10.1146/annurev-ento-010814-021045 . PMID   25341090.
  8. ↑ Huang, J. (2016). "Parapatric genetic introgression and phenotypic assimilation: testing conditions for introgression between Hercules beetles (Dynastes, Dynastinae)". Molecular Ecology. 25 (21): 5513–5526. doi:10.1111/mec.13849. hdl: 2027.42/134423 . PMID   27661063. S2CID   22612044.
  9. 1 2 3 4 Rassart, M.; Colomer, J. F.; Tabarrant, T.; Vigneron, J. P. (2008). "Diffractive hygrochromic effect in the cuticle of the hercules beetle Dynastes hercules". New Journal of Physics. 10 (3): 033014. Bibcode:2008NJPh...10c3014R. doi: 10.1088/1367-2630/10/3/033014 .
  10. 1 2 3 Hinton, H. E.; Jarman, G. M. (1973). "Physiological colour change in the elytra of the Hercules beetle, Dynastes hercules". Journal of Insect Physiology. 19 (3): 533–539. doi:10.1016/0022-1910(73)90064-4..
  11. 1 2 3 4 5 6 7 Toussaint, A. (2015). "Dynastes hercules (Hercules Beetle)" (PDF). The Online Guide to the Animals of Trinidad and Tobago (University of West Indies). Archived (PDF) from the original on 18 February 2018. Retrieved 17 February 2018.
  12. ↑ Dutrillaux B.; Dutrillaux A.-M. (2013). "A South American Origin of the Genus Dynastes (Coleoptera: Scarabaeidae: Dynastinae) Demonstrated by Chromosomal Analyses". Cytogenetic and Genome Research. 147 (1): 37–42. doi:10.1159/000351210. PMID   23735513. S2CID   28561729.
  13. 1 2 Ichiishi, Wataru; Shimada, Shinpei; Motobayashi, Takashi; Abe, Hiroaki (2019-01-07). "Completely engaged three-dimensional mandibular gear-like structures in the adult horned beetles: reconsideration of bark-carving behaviors (Coleoptera, Scarabaeidae, Dynastinae)". ZooKeys (813): 89–110. doi: 10.3897/zookeys.813.29236 . ISSN   1313-2970. PMC   6331513 . PMID   30647528.
  14. ↑ Krell, F., Krell, V. Longevity of the Western Hercules beetle, D. grantii Horn (Coleoptera: Scarabaeidae: Dynastinae). The Coleopterists Bulletin, vol. 69, 2015, 1p.
  15. ↑ "Dynastes hercules". Animal Diversity Web .
  16. 1 2 Kulikowski, A. "Dynastes hercules". Animal Diversity Web. Archived from the original on 2017-05-22. Retrieved 2017-05-20.
  17. ↑ Beebe, W. (1947). "Notes on the Hercules Beetle, Dynastes hercules (Linn.), at Rancho Grande, Venezuela, with special reference to combat behavior". Department of Tropical Research, New York Zoological Society. 32: 109–116.
  18. ↑ "Hercules Beetles". University of Kentucky Entomology. 2008. Archived from the original on 2017-03-30. Retrieved 2017-05-19.
  19. ↑ Kram, R. (1996). "The Journal of Experimental Biology" (PDF). 199: 609–612. Archived (PDF) from the original on 2017-08-10. Retrieved 2017-05-19.{{cite journal}}: Cite journal requires |journal= (help)
  20. ↑ Leerawatthanakun, Sitipon; Charoenwongpaiboon, Thanapon; Klaewkla, Methus; Chunsrivirot, Surasak; Sirirak, Jitnapa; Sriwitool, Tanin-ek; Wangpaiboon, Karan; Pichyangkura, Rath (2022-03-01). "High surfactant-tolerant β-mannanase isolated from Dynastes hercules larvae excrement, and identification of its hotspot using site-directed mutagenesis and molecular dynamics simulations". Enzyme and Microbial Technology. 154: 109956. doi:10.1016/j.enzmictec.2021.109956. ISSN   0141-0229. PMID   34871822. S2CID   244473370.
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