Background
Caligo is a family of large, striking insects known as the Owl Butterflies. Named for their large eyespot on the hindwing, which gives the impression of a much larger animal such as an Owl, this adaptation evolved for two main purposes: it is both a deterrant to predators and a signal for mate selection, whereby female butterflies are attracted to the eye markings of males at rest.
These butterflies have become a staple of butterfly house exhibits and zoos across the world, due to their appearance and interesting behaviour. In addition to the intricate eye spots and excellent camoflage on the underside of the wings, the upperside of Caligo butterflies is typically brightly coloured in shades of blue and yellow, depending on the species - these colours are visible when the butterflies have their wings open in flight, where striking metallic flashes can be seen as they glide through the air between trees and vines.
Native to Central and South America, these butterflies enjoy warm, humid, and shady environments, typically inhabiting the forest understory. The butterflies are predominantly crepuscular, meaning they are active during dawn and dusk, when the sun is not at its full strength and therefore temperatures are more moderate - in fact, the butterflies will remain active at temperatures as low as 12 degrees!
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Eggs
Eggs should be kept in closed plastic containers to prevent them drying out. Typically, eggs will start out a white-grey colour, darkening to black as they near hatching. The darkening indicates the caterpillar is fully developed within the egg, and should then hatch within a couple of days. They will benefit from extra humidity at this time, which can be applied by finely misting the inside lid of the container - do not spray directly onto the eggs or allow them to sit in water droplets as the egg shell is permeable and this can drown the embryo or cause mould to grow, killing the developing caterpillar before it can hatch. For this same reason, do not add host plant leaves to the container with unhatched eggs as the leaves release moisture.
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Caterpillars
When the caterpillars begin to hatch, it is best to move them to a new container with host plant leaves - use a finger or a small/fine paint brush to move them. It is best to continue rearing caterpillars in plastic containers until the third instar so that they do not dehydrate. Once the larvae have established and are feeding well, they can be moved to mesh cages or larger plastic containers if preferred. Larger larvae do very well on living host plants if you have some potted or in a greenhouse.
Owl butterfly caterpillars will accept any of the following host plants: Banana (Musa & Ensete); Ginger (Zingiber); Heliconia; Bamboo; Canna Lilies; Bird of Paraidse (Strelizia); Cypres grass; various Reeds and other broad-leaved grasses are also accepted.
Young larvae tend to live in groups, often moving around the host plants in a long line, 2-3 caterpillars wide and several in length - particularly when kept in a naturalistic setup. The early stages have a yellowish-green colour, changing to green and then brown as they grow, with a spiked head case.
In the wild in South and Central America, Owl Butterflies are considered a pest species on Banana plantations, where they can decimate entire plants overnight, quickly moving onto the next! Their vigorous appetite makes these caterpillars easy to rear in captivity.
