|Some 20 species|
Owl butterflies are very large, 65–200 mm (2.6–7.9 in), 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 predators are around. The Latin name may possibly refer to their active periods; caligo means darkness.
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
- Caligo bellerophon Stichel, 1903
- Caligo brasiliensis (C. Felder, 1862) – Brazilian owl, almond-eyed owl
- Caligo eurilochus (Cramer, ) – forest giant owl
- Caligo idomeneus (Linnaeus, 1758) – Idomeneus giant owl
- Caligo illioneus (Cramer, ) – Illioneus giant owl
- Caligo memnon (C. & R. Felder, ) – 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:
- C. atreus species group:
- C. oileus species group
- C. beltrao species group
- Caligo beltrao (Illiger, 1801) – purple owl
- incertae sedis
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. The main predators of Caligo are apparently small lizards such as Anolis.
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. In some butterflies, particularly Satyrinae (such as the gatekeeper butterfly 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.
- 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.
- 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.
- "Caligo Hübner, " at Markku Savela's Lepidoptera and Some Other Life Forms
- Glassberg, J. (2007). A Swift Guide to the Butterflies of Mexico and Central America. Sunstreak Books. p.132.
- 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.
- 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.
- Garwood, K. M., Lehman, Carter, W., & Carter, G. (2007). Butterflies of Southern Amazonia. Mission, Texas: Neotropical Butterflies.
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