Butterfly Biodata:
Genus: Celaenorrhinus Hübner, 1819
Species: asmara Butler, 1879
Sub-species: asmara Butler, 1879
Wingspan of Adult Butterfly: 40mm
Caterpillar Local Host Plant: Jasminum elongatum (Oleaceae, common names: Common Malayan Jasmine, 扭肚藤).
A male White Banded Flat.
Physical Description of Adult Butterfly:
A female White Banded Flat.
Field Observations of Butterfly Behaviour:
This species is rare in Singapore and its distribution is restricted to a few areas in the offshore island of Pulau Ubin. A small colony was rediscovered in 2011, and since then sightings have been very infrequent. As is the case for the Tagiades species, the adults have the habit of perching on the underside of a leaf between flights, and with its wings opened flat. The adults are also active only during the few hours after sunrise.
Early Stages:
To date only one local host plant, Jasminum elongatum, has been recorded for the White Banded Flat. This plant can be found growing at a few sites on Pulau Ubin, as well as being cultivated in multiple parks and gardens on the main island. Outside Singapore, Clerodendrum fragrans has also been recorded as the larval host. The caterpillars of the White Banded Flat feed on leaves of the host plant. When not feeding, the caterpillars seek safety and concealment in a leaf shelter formed by cutting and folding a leaf fragment along the edge of the leaf.
Local host plant: Jasminum elongatum.
The eggs of the White Banded Flat are laid singly on the underside of a leaf of the host plant. At times, several eggs can be found on different parts of the same leaf as a result of different oviposition visits by the same or different female. The whitish egg is hemispherical with surface marked with longitudinal ridges running from the pole to the rim of the base. Each egg has a basal diameter of about 1mm.
An egg of the White Banded Flat found on the underside of a leaf of the host plant.
Two views of an egg of the White Banded Flat.
The egg takes about 5 days to hatch. The young caterpillar emerges by eating away the polar part of the egg shell. The rest of the egg shell is not eaten by the newly hatched which is about 2.2-2.3mm in length. The yellowish body is roughly cylindrical in shape and the head capsule is black or dark reddish brown in color. A prominent, black collar mark is present on the dorsum of the prothorax.
Left: mature egg. Right: empty egg shell.
Two views of a newly hatched
caterpillar of White Banded Flat cutting leaf lamina for its first leaf shelter, length: 2.3mm.
The newly hatched makes its way to the leaf edge to construct its very first leaf shelter right away. Typically the cut-out leaf fragment is turned over and secured to the upperside of the leaf. The caterpillar ventures out of the shelter from time to time to feed on the leaf lamina in the vicinity. As the caterpillar grows, the body assumes a green undertone. After reaching about 5mm in about 4-4.5 days, the caterpillar moults to the 2nd instar.
Top: a newly hatched caterpillar cutting the leaf lamina. Bottom: the completed leaf shelter with the cut-out folded over.
Two views of a 1st
instar caterpillar of the White Banded Flat, length: 3mm.
Two views of late 1st
instar caterpillar of the White Banded Flat, dormant prior to its moult to the next instar.
The body of the 2nd instar caterpillar is pale whitish to yellowish with a green undertone. There is no trace of the black collar mark on the prothorax seen in the 1st instar. The head is black and broadened sideways to two short tips at the upper end. The surface of the body is sparsely dotted with tiny whitish setae. This instar lasts about 5-5.5 days with the body length reaching about 8mm.
Two views of a 2nd instar caterpillar of the White Banded Flat, early in this stage, length: 4.5mm.
Two views of a 2nd instar caterpillar of the White Banded Flat, length: 6.5mm.
Two views of a late 2nd instar caterpillar of the White Banded Flat, dormant prior to its moult.
The 3rd instar caterpillar closely resembles the 2nd instar caterpillar. The head capsule is dark reddish brown but broader sideways and with the two raised tips more prominent. This instar takes about 5.5-6 days to complete with body length reaching about 12-13mm.
Two views of a 3rd instar
caterpillar of the White Banded Flat, early in this stage, length: 7.5mm.
Two views of a 3rd instar
caterpillar of the White Banded Flat, length: 9mm.
Two views of a late 3rd instar caterpillar of the White Banded Flat, dormant prior to its moult.
The 4th instar caterpillar is little changed from the 3rd instar in all body features. The head capsule is reddish brown soon after the moult, but turned dark reddish brown moments later. This penultimate instar lasts about 7.5-8.5 days with body length reaching about 20mm.
Two views of a 4th instar
caterpillar of the White Banded Flat, early in this instar.
Two views of a 4th instar caterpillar of the White Banded Flat, length: 16mm.
Two views of a 4th instar caterpillar of the White Banded Flat, length: 19.5mm.
A leaf shelter of a 4th instar caterpillar of the White Banded Flat (top right leaf) sighted in the wild.
Two views of a
late 4th instar caterpillar, dormant prior to its moult. Genus: Celaenorrhinus Hübner, 1819
Species: asmara Butler, 1879
Sub-species: asmara Butler, 1879
Wingspan of Adult Butterfly: 40mm
Caterpillar Local Host Plant: Jasminum elongatum (Oleaceae, common names: Common Malayan Jasmine, 扭肚藤).
Physical Description of Adult Butterfly:
On the upperside, the wings are brown. On the forewing, there are hyaline subapical spots in each of spaces 6,7 and 8. There is also an oblique discal band extending from cell-end to vein 2. On the hindwing, there are some obscure darker brown markings.
Underneath, the wings are similarly marked as per above. The male has erectile hair tuft on the hind tibia which gives the legs a rather hairy appearance.
Field Observations of Butterfly Behaviour:
This species is rare in Singapore and its distribution is restricted to a few areas in the offshore island of Pulau Ubin. A small colony was rediscovered in 2011, and since then sightings have been very infrequent. As is the case for the Tagiades species, the adults have the habit of perching on the underside of a leaf between flights, and with its wings opened flat. The adults are also active only during the few hours after sunrise.
Early Stages:
To date only one local host plant, Jasminum elongatum, has been recorded for the White Banded Flat. This plant can be found growing at a few sites on Pulau Ubin, as well as being cultivated in multiple parks and gardens on the main island. Outside Singapore, Clerodendrum fragrans has also been recorded as the larval host. The caterpillars of the White Banded Flat feed on leaves of the host plant. When not feeding, the caterpillars seek safety and concealment in a leaf shelter formed by cutting and folding a leaf fragment along the edge of the leaf.
The eggs of the White Banded Flat are laid singly on the underside of a leaf of the host plant. At times, several eggs can be found on different parts of the same leaf as a result of different oviposition visits by the same or different female. The whitish egg is hemispherical with surface marked with longitudinal ridges running from the pole to the rim of the base. Each egg has a basal diameter of about 1mm.
The egg takes about 5 days to hatch. The young caterpillar emerges by eating away the polar part of the egg shell. The rest of the egg shell is not eaten by the newly hatched which is about 2.2-2.3mm in length. The yellowish body is roughly cylindrical in shape and the head capsule is black or dark reddish brown in color. A prominent, black collar mark is present on the dorsum of the prothorax.
The newly hatched makes its way to the leaf edge to construct its very first leaf shelter right away. Typically the cut-out leaf fragment is turned over and secured to the upperside of the leaf. The caterpillar ventures out of the shelter from time to time to feed on the leaf lamina in the vicinity. As the caterpillar grows, the body assumes a green undertone. After reaching about 5mm in about 4-4.5 days, the caterpillar moults to the 2nd instar.
The body of the 2nd instar caterpillar is pale whitish to yellowish with a green undertone. There is no trace of the black collar mark on the prothorax seen in the 1st instar. The head is black and broadened sideways to two short tips at the upper end. The surface of the body is sparsely dotted with tiny whitish setae. This instar lasts about 5-5.5 days with the body length reaching about 8mm.
The 3rd instar caterpillar closely resembles the 2nd instar caterpillar. The head capsule is dark reddish brown but broader sideways and with the two raised tips more prominent. This instar takes about 5.5-6 days to complete with body length reaching about 12-13mm.
The 4th instar caterpillar is little changed from the 3rd instar in all body features. The head capsule is reddish brown soon after the moult, but turned dark reddish brown moments later. This penultimate instar lasts about 7.5-8.5 days with body length reaching about 20mm.
The 5th instar caterpillar has similar body markings as in the 4th instar initially. As in the 4th instar, the head capsule is bright reddish brown after the moult, but turning dark reddish brown moments later. As growth progresses in this instar, a thin yellowish lateral band appears on each side of the body. In this instar, and sometimes in the 4th instar, the leaf shelter is constructed from joining two adjacent leaves together. The 5th instar lasts for about 8-9 days, and the body length reaches up to 28-29mm.
On the last day of 5th instar, the body decolorises to a very pale whitish shade of yellowish green. The
caterpillar ceases feeding and confines itself to the leaf shelter. The pre-pupatory larva prepares for the pupal phase with a series of silk construction work with the main pieces being
a silk girdle across the
dorsum of its early abdominal segments, and a short and thickened
transverse silk
band on the substrate at its posterior end. Soon the pre-pupatory larva becomes
dormant in its leaf shelter. Pupation takes place about 1 day later.
The girdled pupa is secured with
its cremaster attached to the short transverse band on the substrate. It has a short thorax, a rather long abdomen, a pointed brown rostrum and two lateral brown cephalic processes. The body is pale whitish beige brown in the abdomen but yellowish green in the thorax and wing pads. There are two brownish patches on the upper part of the wing pad. The ventrum of the thorax has a remarkable convex downward outline. Length of pupae: 22mm.
After about 6.5-7 days of pupal
development, the pupal turns dark in the wing pad and thorax areas. The white discal band is also visible at this time. The following day, the adult butterfly emerges from the pupal case.
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.
- A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2nd Edition, 2015.
I would like to express my gratitude to Timothy Liew, Loh Jian Kai and Zick Soh for sharing information on the host plant and early stages of the White Banded Flat.
Text by Horace Tan, Photos by Loh Mei Yee, Low Jian Kai, Sebastian Ow, Zick Soh, Anthony Wong, Khew SK and Horace Tan.
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