(Eurema brigitta senna)
The genus Eurema is represented by at least six species in Singapore. These Grass Yellows are generally abundant - sometimes in large numbers congregating at puddling spots, and in some years, obviously noticeable when they fly in numbers in various areas in Singapore.
In Oct 2006, whilst photographing the newly-discovered Tawny Coster at an open wasteland in the north-eastern part of Singapore, ButterflyCircle members observed a small colony of Grass Yellows flying in the vicinity of some Leguminous bushes.
The host plant, which appeared familiar at first, was however different from the typical Mimosa spp that is usually found in these wastelands. Also, this plant did not possess the thorny stems present in the Mimosa. Upon scrutinising some of the photos taken of this Grass Yellow, it was discovered that this species was the No Brand Grass Yellow (Eurema brigitta senna). Despite its rather unglamorous name, this species was not recorded in recent years until this chance re-discovery.
A particularly 'heavily-freckled' male No Brand Grass Yellow resting in the shade
A female No Brand Grass Yellow ovipositing on a leaf of its host plant
The caterpillars are light green with a lateral grey dorsal stripe and a yellow-green lateral stripe through the length of its body. The caterpillar feeds on the small leaflets of the host plant and stays on the mid-rib of the bi-pinnate leaves, eating voraciously.
An empty pupal shell of the No Brand Grass Yellow on the stem of the host plant after eclosion of the adult butterfly
The No Brand Grass Yellow has managed to survive at the host plant site for over a year and a half after its first sighting. The fate of this species hangs in the balance, as it is critically dependent on the availability of the host plant in an area which is slated for future residential development. For how long the site will be kept in its "wasteland" status is unknown, but in Singapore, the site is unlikely to be left status quo indefinitely.
Perhaps a programme for the cultivation of the host plant in a few protected areas in the nature reserves should be considered, if this species is to be conserved and continue its existence as part of the fauna of Singapore.
Text & Photos by Khew SK
- Keng, H. (1990) Concise Flora of Singapore
- The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
- Butterflies of West Malaysia and Singapore, W.A. Fleming, 2nd Edition, Longman