The owl butterflies are

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of the genus ''Caligo'' and are known for their huge eyespots, which resemble

owl Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

s' eyes. They are found in the

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s and

secondary forest A secondary forest (or second-growth forest) is a forest or woodland area which has re-grown after a timber harvest or clearing for agriculture, until a long enough period has passed so that the effects of the disturbance are no longer evident. ...

s of Mexico, Central and South America. Owl butterflies are very large, , and fly only a few meters at a time, so avian predators have little difficulty in following them to their settling place. However, the butterflies preferentially fly in dusk, when few avian

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s are around. The Latin name may possibly refer to their active periods; '' caligo'' means darkness. Some owl butterflies form

leks A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. A lek can also indicate an avail ...

in mating behavior.

Species

Listed alphabetically within groups: There are some twenty species in this genus, which can be divided into six groups that might constitute subgenera. Some species are of uncertain placement with regard to these groups, however: * ''C. eurilochus''

species group In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

** '' Caligo bellerophon'' Stichel, 1903 ** ''

Caligo brasiliensis ''Caligo brasiliensis'', the Brazilian owl, sulanus owl, or almond-eyed owl,Glassberg, J. (2007). ''A Swift Guide to the Butterflies of Mexico and Central America.'' Sunstreak Books, p.132. is a butterfly of the family Nymphalidae. The species ca ...

'' (C. Felder, 1862) – Brazilian owl, almond-eyed owl ** '' Caligo eurilochus'' (Cramer, 775 – forest giant owl ** '' Caligo idomeneus'' (Linnaeus, 1758) – Idomeneus giant owl ** ''

Caligo illioneus ''Caligo illioneus'', the Illioneus giant owl, is an owl butterfly belonging to the Nymphalidae, nymphalid family, Morphinae subfamily, tribe Brassolini.775 – Illioneus giant owl ** '' Caligo memnon'' (C. & R. Felder, 867 – giant owl, pale owl ** '' Caligo prometheus'' (Kollar, 1850) ** '' Caligo suzanna'' (Deyrolle, 1872) ** '' Caligo telamonius'' (C. & R. Felder, 1862) – yellow-fronted owl ** '' Caligo teucer'' (Linnaeus, 1758) – Teucer giant owl * ''C. arisbe'' species group: ** '' Caligo arisbe'' Hübner,

822 __NOTOC__ Year 822 ( DCCCXXII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire * Byzantine general and usurper Thomas the Slav continues his revolt ...

/small> ** '' Caligo martia'' (Godart, 824 ** '' Caligo oberthurii'' (Deyrolle, 1872) * ''C. atreus'' species group: ** '' Caligo atreus'' (Kollar, 1850) – yellow-edged giant owl ** '' Caligo uranus'' Herrich-Schäffer, 1850 – yellow-bordered owl * ''C. oileus'' species group ** '' Caligo oedipus'' Stichel, 1903 – boomerang owlGlassberg, J. (2007). ''A Swift Guide to the Butterflies of Mexico and Central America''. Sunstreak Books. p.132. ** '' Caligo oileus'' C. & R. Felder, 1861 – Oileus giant owl ** '' Caligo placidianus'' Staudinger, 1887 – placid giant owl ** '' Caligo zeuxippus'' Druce, 1902 * ''C. beltrao'' species group ** '' Caligo beltrao'' (Illiger, 1801) – purple owl * ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'' ** '' Caligo euphorbus'' (C. & R. Felder, 1862) – Euphorbus giant owl ** '' Caligo superbus'' Staudinger, 1887 File:Caligo idomeneus idomeneus MHNT.jpg, '' Caligo idomeneus'' - MHNT File:Caligo teucer semicaerulea MHNT.jpg, '' Caligo teucer'' - MHNT File:Boomerang Owl, Tambopata, Peru.jpg, '' Caligo oedipus'' File:Yellow-fronted owl-butterfly (Caligo telamonius).jpg, ''Caligo telamonius''
in Costa Rica

Functions of the wing pattern

The underwing pattern is highly cryptic. It is conceivable that the eye pattern is a generalized form of

mimicry In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...

. It is known that many small animals hesitate to go near patterns resembling eyes with a light-colored

iris Iris most often refers to: *Iris (anatomy), part of the eye *Iris (mythology), a Greek goddess * ''Iris'' (plant), a genus of flowering plants * Iris (color), an ambiguous color term Iris or IRIS may also refer to: Arts and media Fictional ent ...

and a large

pupil The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black ...

, which matches the appearance of the eyes of many predators that hunt by sight. According to the

Batesian mimicry Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on bu ...

theory the pattern on the wings of ''Caligo'' resemble the head of a predator like a

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

or an

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

. It should deter predators while resting, feeding, mating, or emerging from the

pupa 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 ...

. The role of eyespots as antipredator mechanisms has been discussed since the 19th century. Several hypotheses are suggested to explain their occurrence. In some butterflies, particularly

Satyrinae The Satyrinae, the satyrines or satyrids, commonly known as the browns, are a subfamily of the Nymphalidae (brush-footed butterflies). They were formerly considered a distinct family, Satyridae. This group contains nearly half of the known divers ...

(such as the

gatekeeper butterfly The gatekeeper or hedge brown (''Pyronia tithonus'') is a European species of butterfly. Given its preference for warmer weather, the restriction of range expansion can be assumed to be due to climate. Colonies vary in size depending on the avai ...

and the grayling), it has been shown that ocelli (eyespots) serve as a decoy, diverting bird attack away from the vulnerable body, and towards the outer part of the hindwings or the forewing tip. Research of Stevens et al. (2008), however, suggests that eyespots are not a form of mimicry and do not deter predators because they look like eyes. Rather the conspicuous contrast in the patterns on the wings deter predators. In this study, however, the influence of surrounding forms, like the head region of a predator, was not tested. Also the question why animals evolved such complex imitations of other species is left unanswered.

References

External links

Images representing ''Caligo''
at

Consortium for the Barcode of Life The Consortium for the Barcode of Life (CBOL) was an international initiative dedicated to supporting the development of DNA barcoding as a global standard for species identification. CBOL's Secretariat Office is hosted by the National Museum of ...

Pictures of an owl butterflyMicropanorama of an owl butterfly wingTaxonomy Browser
Upperside and underside photographs.

In Japanese but with

binomial names In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

Pictures of an owl butterflies from Kenya
{{Taxonbar, from=Q857483 Nymphalidae of South America Taxa named by Jacob Hübner

Species

Functions of the wing pattern

References

Further reading

External links