Butterfly of the Month - April 2023

The Small Green-banded Blue (Psychonotis caelius) is a member of the Lycaenidae, our ‘blue’ butterfly family. Despite a wingspan of only 30mm for the male and 32mm for the female the looks are striking. The wing undersides of both male and female are very similar with their black base colour and broad white bands going across hind and forewing ending in a narrow curved band near the apex of the forewing. Narrow green iridescent bands run parallel to the upper margins of the forewing and are present at the base of the hindwing. A wider iridescent green band surrounds black spots going across the opposite end of the hindwing.

The upper wing view allows for easier distinguishing between genders. The wing colour of the male butterfly is dominated by a bright light blue with a tinge of mauve and a band of white of substantial width on the hindwing. Only on the odd occasion does a central white patch appear on the forewing. The outer edges of fore and hindwing are black. The upper side of the female is dominated by its black wing colour, but shows iridescent greenish blue at the base of both wings and an expansive white band running across the hindwing but only partially across the forewing.

Tiny white eggs of an intricate surface pattern are laid singly or in twos alongside the veins on the underside of the host plant leaves. They hatch to become larvae with flattened bodies and are of a pale green colour that blends perfectly with the leaf colour. The pupa colour is partly beige and with substantial brown markings as the image shows. It also has shows short hairs. The immature stages are rarely attended by ants.

In Brisbane the larval host plant is the Soap Tree or Red Ash (Alphitonia excelsa), a common tree usually but not only found in open forest settings.

The Small Green-band Blue is on the wing throughout the year.

Images: 

CM - Cliff Meyer; GW - Geoff Walker; PS - Peter Samson