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Common Grass-blue Butterfly - Zizina labradus
The Zizina genus has only one species, but belongs to the Lycaenidae family, which according to the Australian Faunal Directory currently has 45 genera and 143 species. Commonly this group of butterflies are called Blues, Coppers and Hairstreaks. Interestingly, many have a strong association with ants that will tend them at the larval stage and protect them from predators.
A paper titled THE ECOLOGY AND EVOLUTION OF ANT ASSOCIATION IN THE LYCAENIDAE (LEPIDOPTERA) by N E Pierce, M F Braby, A Heath, D J. Lohman, J Mathew, D B. Rand and M A. Travassos, goes into some depth about the types of association these butterflies have with ants. It involves the payment by the butterfly larva of a sweet secretion, and/or chemical and sound mimicry. It is far too involved to detail here, but can be read online at http://www.dnp.go.th/FIG/biodiversity/Pierce2002AnnualReview.pdf
According to the excellent paperback called ‘The Complete Field Guide to Butterflies of Australia’ by Michael F Braby, the Common Grass-blue Butterfly larvae is attended by a number of ant species although some butterflies in this family have a very specific and complex relationship with a single ant species.
Zizina labradus is a very common butterfly and ranges over much of Australia. Locally it can occur in large numbers, particularly when a heavy nectar producing plant with a powerful honey perfume is in bloom; otherwise it slowly flusters around feeding on whatever takes its fancy. They are relatively easy to approach and will usually continue to siphon up nectar providing you do not make sudden movements.
The easiest way to distinguish this species from other local Blues is by the smooth rounded shape of the hind wings; the others have small projections. Also the markings on the rear of the wings are not as clearly marked as other species that have more sharply defined spots and markings. Size wise it is around 1 cm (3/8”) in head/body length, with a wingspan of 2 cm or ¾” (female is slightly larger).