Introduction
Butterflies in the genus Celaenorrhinus are known as ‘flats’ due to their habit of resting with their wings outspread and flattened against a leaf or other substrate. Many of the species have a pattern of hyaline ‘windows’ in the forewings, and some such as the beautiful African species galenus are marked with bands or blotches of almost luminous golden-orange.
The genus is widespread in tropical and subtropical regions of the world, with 24 species found in the neotropics including 5 which reach as far north as Mexico; 45 species in Africa, and 51 species in the Oriental region including at least 22 found in India.
Celaenorrhinus leucocera is a localised but reasonably common species which is found from Assam and Myanmar to Thailand and peninsular Malaysia.
Habitats
This butterfly is found in open areas within subtropical humid forests at altitudes between about 400-1800m.
Lifecycle
I have no data relating to leucocera but the following is applicable to the genus Celaenorrhinus in general:
The eggs are typically large, dome-shaped, greenish in colour, and laid singly on the underside of leaves of trees and shrubs in the family Acanthaceae, including Asystasia, Ecbolium, Eranthemum, Nilgirianthus, Carvia and Thelepapale.
After hatching the larva eats its eggshell and then constructs a cell made from folding over a piece of leaf and fastening it with silk. After each moult it constructs a new cell, and when larger it uses a pair of leaves sealed together with numerous silk strands. It lives and feeds within these cells for its entire life. If the leaf cell is opened the larva defends itself by arching its front quarters over its back and splaying its legs, thus creating the illusion that it is not a harmless larva but an aggressive ant. When fully grown a Celaenorrhinus larva is typically translucent dark green, covered in very short whitish hairs, and with a large dark coloured head.
Pupation takes place in a newly formed cell constructed from living foliage or dead leaf litter. The pupae are typically cylindrical, widest at the thorax, tapering towards the head and gently towards the rear.
Adult behaviour
The adults have an extremely rapid flight, twisting and turning evasively before eventually settling under the leaves of ferns and other vegetation. They prefer to fly in hot sunny conditions, but in cool conditions are still remarkably alert and capable of rapid manoeuvres. In hazy weather they often bask on rocks or boulders in the vicinity of rivers.