Butterfly of the Month - January 2023

You can't miss the Lesser Wander (Danaus petilia) with its wingspan of around 60mm.The butterfly is a member of the family Nymphalidae and within that of the Danainae, a sub-family it shares with Blue Tiger (Tirumala hamata), Swamp Tiger (Danaus affinis), Monarch (Danaus plexippus), Common Crow (Euploea corinna) and others. Long considered a sub-species of Danaus chrysippus, D. petilia has been reinstated as its own species occurring east of Lydekker’s Line which by biogeography defines the start of the Australian faunal realm. The butterfly is widespread across most parts of Australia.

The orange wings of Danaus petilia have black margins with small white spots. A white irregular band crosses the upper part of the forewing. Between the band and the apex the wing is coloured pale orange. The hindwings carry small black spots, irregularly placed. Sex scales are clearly visible on the upper side of the male’s hindwing as can be seen in the left top image.

The Lesser Wanderer starts its life cycle with a tiny cream coloured egg, covered in grooves and ridges and narrowing at the top. It is laid singly on the larval host plant.

The larva shows broad black bands with large yellow spots running across its body at each segment, and narrow ones between them. Three pairs of black filaments resembling tentacles show a red base in later instars like in the photo here.

The pupa is usually green but may also be pink. Examples of healthy pupae are depicted above. Please note,  the third pupa to the right of the green and pink ones has likely been stung by a wasp and is dead. It displays the typical colours for this to have happened.. Please note the band of tiny golden spots around the thorax on all pupae.

While there are quite a few introduced plants supporting the Lesser Wanderer, in and around Brisbane it thrives on native plants of the Dogbane or Milkweed family (Asclepiadoideae) including Mangrove Waxflower (Vincetoxicum carnosum formerly Cynanchum carnosum), Coast Tylophora (Vincetoxicum polyanthum formerly known as Tylophorum benthamii), Small-leaved Tylophora (Vincetoxicum grandiflorum formerly T. grandiflorum), Thin-leaved Tylophora (Vincetoxicum paniculatum formerly T. paniculatum), misc. Milkvines (Leichardtia spp formerly Marsdenia spp), We always suggest supporting our native fauna by planting native flora.

Adults are easily seen when on the wing and known for their comparatively slow flight behaviour. Adults are also known to move en masse, however, there is no pattern to these movements, no regular route, nor repeat timing. While they seem to search for favourable conditions like migrating butterflies do, scientists are hesitant to call the mass movements migration.

Images:

CM – Cliff Meyer; JG – Jutta Godwin; MV – Museum Victoria CC-BY, Ross Field and Simon Hinkley; PC – Peter Chew, Brisbane Insects; SA – Sylvia Alexander