Mechanitis

Mechanitis is a genus of butterflies in the tribe Ithomiini, commonly known as tigerwings. They were named by Johan Christian Fabricius in 1807. They are in the brush-footed butterfly family, Nymphalidae. Members of the genus Mechanitis were named for the machine-like metallic appearance of the chrysalis in certain species such as the Mechanitis polymnia. The chrysalises have a reflective chitin coating with a metallic appearance.

Mechanitis
Mechanitis polymnia
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Nymphalidae
Tribe: Ithomiini
Genus: Mechanitis
Fabricius, 1807
Species

See text

Synonyms
  • Nereis Hübner, [1806]
  • Hymenitis [Illiger], 1807
  • Epimetes Billberg, 1820

Taxonomy

Mechanitis was described by Johan Christian Fabricius in 1807.[1] Members of the genus Mechanitis in the brush-footed butterfly family, Nymphalidae.[2] Mechanitis are in the Ithomiini tribe which includes other Neotropical species of butterflies. The classification of Mechanitis, when based entirely on appearance of wing pattern and color is inaccurate because of the incidence of polymorphic butterflies. When wing patterns are similar the accuracy in identifying butterfly species is improved with the use of ecological and mitochondrial DNA.[3]

Description
Mechanitis polymnia Chrysalis
Mechanitis lysimnia Caterpillar

Butterflies in the genus Mechanitis are abundant and they are unpalatable.[2] The mature Mechanitis butterflies in the genus have warning colors which are black, orange, and yellow. They also have tiger patterns on their wings.[4] The butterfly gets the name Mechanitis from the chrysalises of the genus, which have a machine-like quality.[5] They are thin and small bodied butterflies with rounded wings and long yellow antennae.[5] The size of the adult or imago Mechanitis butterfly is 65–75 mm.[6]

Life history

The species are primarily forest butterflies and they are found at sea level and as high as 3,000 feet (910 m) above sea level in rainforests and humid forests.[3] Female members of the genus Mechanitis lay their eggs in clusters on the small hairs found on the leaves of poisonous plants in the genus of solanum and in the family Apocynaceae.[7] When the elongated white eggs hatch, the larva – caterpillars – feed in groups on the foliage.[8] Some eggs clusters are also laid on food plants, which can result in them being destroyed by predators.[9] Up to three egg clusters can be found on one plant, but only one is found per leaf.[9] If a female Mechanitis is disturbed while laying the eggs on the upper side of a leaf, she flies away but returns to the same leaf to continue ovipositing.[9] The egg clusters of the Mechanitis isthmia can range between 30 and 60 eggs.[9] Those plants which are exposed to direct sunlight during most of the day are chosen for ovipositing.[10] Most egg clusters are to be found on leaves less than a meter above the surface.[9] After the eggs develop into larvae, the larvae begin to feed themselves from the leaf on which they were laid, and later move on to other leaves.[10] Feeding is performed in tight groups in intervals.[10] Sometimes one group rests, while another one feeds.[10]

Reflective chrysalis

The pupa – chrysalis – of the Mechanitis polymnia have a mirror-like metallic appearance. The polymnia chrysalises have a reflective coating which conceals the defenseless pupa by reflecting its surroundings to confuse predators. It is thought that predators see their own reflection in the chrysalis and then flee.[11] Another theory is that a reflective exterior does not reduce predation but it may assist the larva in regulating their body temperature while pupating.[12]

The metallic-looking coating of the chrysalis is made of chitin.[13] The substance is also found in coatings on other insects such as jewel beetles. Unlike the jewel beetles, which retain their chitin, the Mechanitis chrysalis loses the reflective coating in about a week.[11] The fragile coating which gives the chrysalis of the Mechanitis its golden sheen is caused by light reflecting on the transparent chitin. The coating is dense, and there are up to 25 transparent layers which lie in the yellow-orange spectrum; the human eye then perceives the coating as gold. The chrysalis begins as blue or greenish, and then appears "golden" or "silver" after about two to four days.[6][7]

Mating

Biologists believe the chemical scent diffusion is influential in mating.[14] When a male butterfly chases another butterfly with a similar color pattern which is recognized as female, he hovers over it, fanning it from the front and back.[14] If the target is recognized as a male, the chasing butterfly usually returns to his original observational place.[14] If the female is receptive to the courting, they try to mate. If they are disturbed during mating, the female usually carries the male to another place to mate.[14] After mating, the butterflies separate again and fly their own ways.[14]

Distribution

Mechanitis are found in the rainforests of South America[11] and in Central America as far north as Mexico.[6] The genus is distributed throughout the humid forests from Mexico to southern Brazil, into Paraguay, and stretching to three of the Caribbean islands. They have also been found in the Andean region of Colombia.[3]

Species

Arranged alphabetically:[15][16]

ImageCaterpillarScientific nameDistribution
Mechanitis lysimnia (Fabricius, 1793) – confused tigerwingsouthern Mexico to Uruguay
Mechanitis mazaeus Hewitson, 1860 – Mazaeus tigerwingSouth America
Mechanitis menapis Hewitson, [1856] – variable tigerwingSouth America
Mechanitis polymnia (Linnaeus, 1758) – disturbed tigerwing, orange-spotted tiger clearwingfrom Mexico to the Amazon rainforest

References
  1. Schulze, Franz (October 1905). Das Tierreich (Nachdruck der Ausgabe von 1894 ed.). Berlin: Verlag von R. Friedlander and Sohn. p. 289. Archived from the original on 11 May 2022. Retrieved 11 May 2022.
  2. Hogue, Charles Leonard (1993). Latin American insects and entomology. Berkeley: University of California Press. p. 351. ISBN 978-0520078499. Archived from the original on 15 May 2022. Retrieved 11 May 2022.
  3. Giraldo, C E; Uribe, S I (24 August 2012). "Taxonomy of Mechanitis (F.) (Lepidoptera: Nymphalidae) from the West Colombian Andes: an Integrative Approach". Neotropical Entomology. 41 (6): 472–484. doi:10.1007/s13744-012-0071-7. PMID 23949672. S2CID 16400560. Archived from the original on 12 May 2022. Retrieved 13 May 2022.
  4. Hill, Ryan I.; Elias, Marianne; Dashmahapatra, Kanchon K.; Jiggins, Chris D.; Koong, Victor; Willmott, Keith R.; Mallet, James (13 June 2012). "Ecologically relevant cryptic species in the highly polymorphic Amazonian butterfly Mechanitis mazaeus s.l. (Lepidoptera: Nymphalidae; Ithomiini)". Biological Journal of the Linnean Society. 106 (3): 540–560. doi:10.1111/j.1095-8312.2012.01874.x. S2CID 51949156. Archived from the original on 11 May 2022. Retrieved 11 May 2022.
  5. Cook, Maria. "How Long Does a Butterfly Stay in a Chrysalis?". Sciencing. Leaf Group Ltd. Archived from the original on 8 February 2022. Retrieved 11 May 2022.
  6. "Golden Dolls". Elements. 3 January 2019. Archived from the original on 12 April 2019. Retrieved 11 May 2022.
  7. Marquis, Robert J.; Koptur, Suzanne (2022). Caterpillars in the middle : tritrophic interactions in a changing world (1st ed.). Cham, Switzerland: Springer. ISBN 978-3030866877. Archived from the original on 15 May 2022. Retrieved 11 May 2022.
  8. King, Andrew B. S.; Saunders, Joseph L. (1984). The invertebrate pests of annual food crops in Central America : a guide to their recognition and control. London: Overseas Development Administration. p. 32. ISBN 978-0902500112. Archived from the original on 15 May 2022. Retrieved 11 May 2022.
  9. Young, Allen M.; Moffett, Mark W. (1979). "Studies on the Population Biology of the Tropical Butterfly Mechanitis isthmia in Costa Rica". The American Midland Naturalist. 101 (2): 309–310. doi:10.2307/2424596. ISSN 0003-0031. JSTOR 2424596. Archived from the original on 11 May 2022. Retrieved 15 May 2022.
  10. Young, Allen M.; Moffett, Mark W. (1979), p. 313
  11. Keartes, Sarah (18 January 2017). "Meet the caterpillars that build chrome homes (PHOTOS)". Earthtouch News Netowrk. Archived from the original on 26 November 2021. Retrieved 11 May 2022.
  12. Franklin, Amanda M.; Rankin, Katrina J.; Rozo, Laura Ospina; Medina, Iliana; Garcia, Jair E.; Ng, Leslie; Dong, Caroline; Wang, Lu-Yi; Aulsebrook, Anne E.; Stuart-Fox, Devi (30 October 2021). "Cracks in the mirror hypothesis: High specularity does not reduce detection or predation risk". Functional Ecology. 36 (1): 239–248. doi:10.1111/1365-2435.13963. hdl:11343/299203. S2CID 240324294. Retrieved 18 May 2022.
  13. "The cocoon of this tropical butterfly looks like a golden jewel". Ulyces. Archived from the original on 29 May 2021. Retrieved 11 May 2022.
  14. Vasconcellos-Neto, Joao; Brown, Keith S. (1982). "Interspecific Hybridization in Mechanitis Butterflies (Ithomiinae): a Novel Pathway for the Breakdown of Isolating Mechanisms". Biotropica. 14 (4): 289–290. doi:10.2307/2388088. ISSN 0006-3606. JSTOR 2388088. Archived from the original on 15 May 2022. Retrieved 15 May 2022.
  15. "Mechanitis Fabricius, 1807" Archived 2017-02-16 at the Wayback Machine at Markku Savela's Lepidoptera and Some Other Life Forms
  16. Glassberg, J. (2007) A Swift Guide to the Butterflies of Mexico and Central America. Sunstreak Book Inc.
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