Butterfly Biodata:
Genus: Rapala Moore, 1881
Species: Species: damona Swinhoe, 1890
Wingspan of Adult Butterfly: 25-28mm
Caterpillar Local Host Plants: Cordia cylindrostachya (Boraginaceae, common names: String Bush, Scorpion Weed, Black Sage), Melastoma malabathricum (Melastomataceae, Singapore Rhododendron) .
Physical Description of Adult Butterfly:
On the upperside, the female is entirely brown whereas the male is deep red with broad black border on the forewing. As with other Rapala spp., the male has an oval-shaped brand in space 7 on the hindwing. On the underside, both sexes are ochreous brown. The markings are typical for Rapala spp, with cell-end bars on both wings, and narrow brown postdiscal bands. In the forewing, the postdiscal band is curved-in at the upper quarter. The hindwing carries a white-tipped filamentous tail at the end of vein 2 with a tornal lobe between veins 1a and 1b. In addition, there is a black tornal spot, a bluish green patch in space 1b (about 80-100% filled), an orange-crowned (either pale orange, yellow or obscure), black sub-marginal spot in space 2, and black post-discal striae in spaces 1b and 2.
Field Observations:
The Malay Red Flash is moderately rare in Singapore. It is mainly found at the fringe of the nature reserves and in some urban parks. The adults are fast flyers and take rapid flights among foliage at forest edges and around their host plants. Adults also visit flowers for their nectary intakes.
Early Stages:
The Malay Red Flash is polyphagous as its early stages feed on host plants from different families. Locally two plants, Cordia cylindrostachya (String Bush) and Melastoma malabathricum (Singapore Rhododendron), have so far been identified as the larval hosts. The caterpillars of the Malay Red Flash feed on flowers and flower buds of the host plants. In the wild, the caterpillars are typically found in the company of small black ants.
Eggs are laid singly on a leaf, on the peduncle and among flower buds on a developing inflorescence. Each egg is about 0.6-0.7mm in diameter, greenish in colour when freshly laid. It is bun-shaped with a depressed micropylar at the pole and a surface reticulated with very fine ridges.
It takes about 3 days for the egg to hatch. The newly hatched is pale yellowish brown with moderately long dorsal and lateral setae. Its body has a length of about 1mm. Pale reddish brown patches can be seen on the dorsum of the metathorax, 1st, 6th-8th abdominal segments. It also has a black prothoracic shield and a black head. After about 2.5 days of growth in the first instar, and reaching a length of about 2mm, the caterpillar moults to the next instar.
The 2nd instar caterpillar is pale yellowish brown in base color and has dark reddish brown patches on the dorsum of the metathorax (the posterior half), as well as in the 1st, 6th-8th abdominal segments. There are short black setae emanating from rows of conical projections occurring dorsally and laterally. The dorsal conical projections are larger and more whitish compared to those occur on later body segments. The 2nd instar caterpillar reaches a length of about 3mm, and after about 2.5 days in this stage, it moults again.
The 3rd instar caterpillar resembles the 2nd instar caterpillar closely, but top of the conical projections of 2nd-6th abdominal segments more whitish, giving rise to the appearance of two parallel whitish bands on the dorsum. Individual caterpillars raised on flowers of the Singapore Rhododendron typically have a strong pink to reddish undertone compared to those raised on String Bush. On the 7th abdominal segment, the dorsal nectary organ is now more readily observed. The 3rd instar takes about 2.5 days to complete with the body length reaching about 5mm before the next moult.
The 4th instar caterpillar again resembles closely the 3rd instar caterpillar. One discernible difference is in the reddish brown patches on the dorsum of the metathorax and 1st abdominal segments. These patches are now somewhat disjoint at the mid-dorsal line. Tentacular organs on the 8th abdominal segment can now be easily observed being everted from time to time. The 4th instar takes about 3 days to complete with the body length reaching up to 10mm.
The 5th instar caterpillar has similar markings as in the 4th instar but with greater separation of the left and right halves of the dorsal reddish brown patches on the metathorax and 1st abdominal segment. The two parallel whitish bands on the 2nd-6th abdominal segments are replaced with disjoint and oblique whitish patches. It is not uncommon to see numerous ants attending to a 5th instar caterpillar in field observations.
After about 4-5 days of feeding and reaching a length of about 19-20mm, the caterpillar stops food intake and wanders around for a pupation site. During this time, its body gradually shortened and body color darkens. Typically the caterpillar chooses a concealed space in a leaf litter for its pupation site.
The pre-pupatory caterpillar prepares for pupation by spinning a silk girdle and a silk pad to which it attaches itself via anal claspers. After about 1 day as a pre-pupa, pupation takes place. The pupa has a shape typical of most lycaenid species with a length of 10-12mm. It is pale reddish to yellowish brown in base colour, and its surface bears numerous small dark speckles.
Eight to nine days later, the pupa darkens, first in the wing pad and thorax, then progressively in the abdomen. The next day, the pupal stage comes to an end with the emergence of the adult butterfly. Pupal period: 9-10 days.
References:
- [C&P5] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, G. and N. van der Poorten (Eds.), 5th Edition, Malayan Nature Society, 2020.
- Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012.
I would like to express my gratitude to Mr Foo Jit Leang and Mr Hanpeng Lim for sharing information on the host plant and early stages of the Malay Red Flash.
Text by Horace Tan, Photos by Hanpeng Lim, Loh Mei Yee, Low Jian Kai, Khew SK, Sebastian Ow, Zick Soh, Jonathan Soong and Horace Tan.
