Southern blue butterfly

Status: Not threatened

Description

The New Zealand blue or Southern blue butterfly (Zizina oxleyi) is the only endemic blue butterfly in New Zealand. It key habitat is in river terraces.

While currently listed as ‘Not Threatened’, the southern blue is in fact under threat from an Australian invading blue butterfly Z. labradus. Our endemic species has already been displaced throughout most of New Zealand by through hybridization with the invasive Australian blue butterfly species. Only populations in the south-east of the South Island are still unaffected.

This highlights the gaps in knowledge and the ability to keep up to date with what’s really happening to our endemic invertebrates. There is a lack of understanding of the mechanism for the southern blue butterfly displacement and the potential for complete displacement. This raises the possibility of extinction. To this end, the Southern blue butterfly has been earmarked as a research priority.

Male upperside

Pale violet-blue, with a silvery sheen in certain lights, forewing: a broad brown edging along the termen, which covers in some specimens quite the outer fourth of the wing, while in others is much narrower. It is always broadest at the apex and is bounded by an anteciliary darker line, beyond which the cilia are brownish at base and white outwardly.

Hindwing: anterior or costal third to half and apex brown; a slender black anteciliary line, beyond which the cilia are as in the forewing.

Female upperside

Brown, with a more or less distinct suffusion of violet-blue at the bases of the wings, on the hindwing continued obscurely along the dorsum; both forewings and hindwings with slender anteciliary lines, darker than the ground colour.