Owl Butterfly

• GeneralThe great eyespots on its wings mimic an owl's eyes to startle predators.
• What its eyespots are actually for is still debated: they may mimic a predator's eye to startle birds, or deflect pecks towards the edge of the wing, away from the body.
• It does not take nectar from flowers: it sips the juice of fallen, rotting fruit, and can become intoxicated on the alcohol of fermentation.
• Its caterpillar is a pest in banana and sugar cane plantations, where it can strip whole plants of their leaves.
• The two huge eyespots on the underside of the hindwings mimic an owl's eyes, which is where the name comes from; they are thought to startle predators or deflect attacks away from the body.
• It does not visit flowers: it drinks the juice of fermenting fruit, above all banana, pineapple and mango, which is why it is attracted with fruit baits.
• It flies at dawn and dusk, when the daytime insect-eating birds have stopped and the bats are not yet out.
• The caterpillar reaches 15 cm and eats banana and heliconia leaves; in Central and South America it is considered a pest of banana plantations.
• The chrysalis mimics a dead leaf flecked with gold.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Rainforest and banana plantations

Size at birth

The first-instar caterpillar is white with two brownish orange bands running the length of the body and ending in two appendages; in later instars it develops hairs that mimic spines and a crown of four horns on the nape

Sexual maturity

The adult feeds mainly on the juices of fermenting fruit, and also on sap and nectar; it flies in half-light, at dawn and dusk, when few visual predators are active

Gestation / incubation

The eggs hatch after 3-5 days; the fertile ones develop a grey ring just above the centre and the infertile ones collapse. The chrysalis lasts 10 to 22 days depending on conditions

Litter / clutch size

The female lays a large number of eggs in dense groups on the leaves of the food plant; the caterpillars feed gregariously along the leaf edges and rest lined up along the veins

Sources consulted: Universidad de las Indias Occidentales; Cambridge Butterfly Conservatory; Wikipedia (Caligo eurilochus); Reiman Gardens, ficha Forest Giant Owl; ficha de especie de Caligo eurilochus; recopilacion sobre el genero Caligo; Ficha de especie de Caligo eurilochus (UWI, datos del Audubon Nature Institute); Reiman Gardens

Best time: On the wing all year in rainforest and secondary forest, from Mexico to the Amazon basin; also in banana plantations