Butterfly of the Month - March 2025
The Wide-brand Grass-dart (Suniana sunias rectivitta) is a common little butterfly in Brisbane, often encountered during our surveys. The wingspan reaches 21mm for the male and 22mm for the female. Members of the Hesperiidae family are notoriously difficult to identify. That results in particular challenges within the subfamily of Hesperiinae to wich Suniana spp and Ocybadistes spp belong. When comparing our little butterfly with i.e. O. walkeri, please note the colour differences.
The upper wing side of both butterflies is dark brown. However, the markings of S. sunias rectivitta are of a more intense orange, and even the underside has more of an orange sheen than the paler colour of O. walkeri. The latter has also markings which are less distinct and blend more into the base colour. Yet, unless you have both butterflies side by side, it’s difficult to see the dinstinguishing features. What does make it somewhat easier, is the outer orange band of markings on the forewing. It runs in a very straight line on a S.sunias wing, whereas on one of O. walkeri it shows irregularities, especially towards the apex. The males of both species show dark sex scales on their forewings.
The butterfly’s immature stages begin with a dome shaped egg, well below 1mm in size, laid singly on its larval host. It starts off in cream colour but develops a reddish band within two days. After hatching, the first instar creates a shelter by cutting into the leaf of its host plant and folding it over. Naturally, the shelter grows with the instar size, in the end needing two leaves being stitched together. Pupation happens in the leaf shelter.
In our image you can see that the later instar will develop into a male butterfly as the larva exhibits two light yellow spots, the gonads which we already pointed out in our Butterfly of the Month of January 2025 when introducing Telicota colon.
Suniana sunias likes the grassy edges of moister forests. It’s main larval host plants are the native Leersia hexandra (Swamp Rice Grass) and – unfortunately - the exotic and only too well known Megathyrus maximus (Guinesa Grass or Green Panic) and Paspalum urvillei (Vasey Grass).
Images:
SA – Sylvia Alexander, and this time a special thank you to WJ - Wesley Jenkinson for having given us a choice of excellent photos.
