Early stage of Pelopidas agna agna (Little Branded Swift , 南亞谷弄蝶)

Early stage of Pelopidas agna agna (Little Branded Swift)


Introduction

Pelopidas agna agna (Little Branded Swift), is very similar to Pelopidas mathias mathias (Small Branded Swift), both are the smallest Pelopidas species in Singapore.

Identifying of the species rely heavily on the male forewing band position versus the 2 radial hyaline spots. The female however, according to several reference, almost impossible to differentiate when compare to P. mathias.

Probably due to small size and difficulties in ID, the species is not in the current Singapore Butterflies Checklist, thus with the discovery, this will be a new addition to the known butterflies fauna in Singapore.

A field shot of Pelopidas agna agna

ID key exert from Butterflies of Hong Kong:
On the forewing upperside, a line through the two cell spots projected backwards passes inward towards the midline, in male passing through the lower end of the brand.



ID key illustration:
Hong Kong Butterflies - Philip Yik-fui Lo | Wing-Leung Hui: The 2 radial hyaline spots, if joined in lines, may reach the end of the brand.

ID key exert from BMP:
- Smaller, forewing less than 20mm. Male upperside forewing with a naroow discal stigma from middle of vein 1b to the spot in space 2.
P. agna (17.5 - 20 mm)
- male upperside forewing lower end of stigma reaches vein 1b slightly closer to the termen than to the wing base. Underside hindwing ochreous without a grey tinge.

ID key illustration:

Male upperside forewing lower end of stigma reaches vein 1b slightly closer to the termen (B) than to the wing base (A).

Early stage observation

Larva found at forest fringe in the leaves shelter on Imperata cylindrica (Lalang). The early stage of this species closely resembled of those of P. mathias. Larva hostplant including Panicum maximum (Guinea Grass).


2nd instar larva



3rd instar larva



4th instar larva



5th instar larva



Pupa



A newly enclosed male of Pelopidas agna agna



Male genitalia (right valva)

Special Acknowledgement:
Dr Laurence G. Kirton (Head of Biodiversity and Conservation of Fauna Branch, Tropical Forest Biodiversity Centre, Forest Research Institute of Malaysia)

Young JJ (HKLS Chairman)




References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006
• The Butterflies of Hong Kong, M.J. Bassombe, G. Johnston, F.S. Bascombe
• Hong Kong Butterflies, Philip Yik-fui Lo, Wing-leung Hui