Owl butterfly

Not to be confused with Calico butterflies.

Owl butterflies
Caligo martia
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Nymphalidae
Subfamily:	Morphinae
Tribe:	Brassolini
Genus:	Caligo Hübner, 1819
Type species
Papilio eurilochus Cramer, 1775
Diversity
Some 20 species
Synonyms
Hamadryas Mikan, 1821 (non Hübner, 1804: preoccupied)

Butterflies in the genus Caligo are commonly called owl butterflies, after their huge eyespots, which resemble owls' eyes. They are found in the rainforests and secondary forests of Mexico, Central and South America.

Owl butterflies are very large, 65–200 millimetres (2.6–7.9 in), and fly only a few metres 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 predators are around.^[1] The Latin name may possibly refer to their active periods. Caligo means darkness.

Some owl butterflies form leks in mating behavior.^[2]

Species

There are some 20 species in this genus, which can be divided into 6 groups that might constitute subgenera. Some species are of uncertain placement with regard to these groups, however:

• C. eurilochus species-group
  • Caligo bellerophon Stichel, 1903
  • Caligo brasiliensis
  • Caligo eurilochus – Forest Giant Owl
  • Caligo idomeneus – Idomeneus Giant Owl
  • Caligo illioneus – Illioneus Giant Owl
  • Caligo memnon
  • Caligo prometheus
  • Caligo suzanna (Deyrolle, 1872)
  • Caligo telamonius (C. & R. Felder, 1862)
  • Caligo teucer – Teucer Giant Owl
    

    Caligo teucer
• C. arisbe species group:
  • Caligo arisbe
  • Caligo martia
  • Caligo oberthurii
• C. atreus species group:
  • Caligo atreus
  • Caligo uranus
• C. oileus species-group
  • Caligo oedipus
  • Caligo oileus – Oileus Giant Owl
  • Caligo placidianus – Placid Giant Owl
  • Caligo zeuxippus
  • "Caligo repugno" – Turquoise Giant Owl
• C. beltrao species-group
  • Caligo beltrao
• incertae sedis
  • Caligo euphorbus – Euphorbus Giant Owl
  • Caligo superbus

Functions of the wing pattern

The underwing pattern is highly cryptic. It is conceivable that the eye pattern is a generalized form of mimicry. It is known that many small animals hesitate to go near patterns resembling eyes with a light-colored iris and a large pupil, which matches the appearance of the eyes of many predators that hunt by sight.^{[citation needed]} The main predators of Caligo are apparently small lizards such as Anolis.^{[citation needed]}

• 

  Anolis carolinensis

• 

  Caligo

• 

  Hyla arborea

According to the Batesian mimicry theory the pattern on the wings of Caligo resemble the head of a predator like a lizard or an amphibian. It should deter predators while resting, feeding, mating or emerging from the pupa.

The role of eyespots as antipredator mechanisms has been discussed since the 19th century. Several hypotheses are suggested to explain their occurrence.^[3] In some butterflies, particularly Satyrinae (such as the Gatekeeper Butterfly and the Grayling), it has been shown that ocelli 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 eye-spots 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.^[4] 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.

References

1. ^ André V. L. Freitas, Woodruff W. Benson, Onildo J. Marini-Filho & Roberta M. de Carvalho (1995). "Territoriality by the dawn's early light: The neotropical owl butterfly Caligo idomenaeus (Nymphalidae: Brassolinae)" (PDF). Journal of Research on the Lepidoptera 34 (1–4): 14–20. http://lepidopteraresearchfoundation.org/pdf/pdf34/34-014.pdf. 
2. ^ Robert B. Srygley & Carla M. Penz (1999). "Lekking in neotropical owl butterflies, Caligo illioneus and C. oileus (Lepidoptera: Brassolinae)". Journal of Insect Behavior 12 (1): 81–103. doi:10.1023/A:1020981215501. 
3. ^ Martin Stevens (2005). "The role of eyespots as anti-predator mechanisms, principally demonstrated in the Lepidoptera". Biological Reviews 80 (4): 573–588. doi:10.1017/S1464793105006810. PMID 16221330. 
4. ^ Martin Stevens, Chloe J. Hardman & Claire L. Stubbins (2008). "Conspicuousness, not eye mimicry, makes "eyespots" effective antipredator signals" (PDF). Behavioral Ecology 19 (3): 525–531. doi:10.1093/beheco/arm162. http://www.oxfordjournals.org/our_journals/beheco/press_releases/freepdf/arm162.pdf. 

Further reading

• Garwood, K. M., Lehman, Carter, W., & Carter, G. (2007). Butterflies of Southern Amazonia. Mission, Texas: Neotropical Butterflies.

External links

• Pictures of an owl butterfly
• Micropanorama of an owl butterfly wing
• Taxonomy Browser Upperside and underside photographs.
• Pteron In Japanese but binomial names