Butterfly Biodata:
Genus: Cepora Billberg, 1820
Species: iudith Fabricius, 1787
Subspecies: malaya Fruhstorfer, 1899
Wingspan of Adult Butterfly: 45-55mm
Caterpillar Local Host Plants: Capparis micracantha (Capparaceae, common name: Thorn Caper, 小刺山柑), Crateva magna (Capparaceae, common name: Large Garlic Pear).
Physical Description of Adult Butterfly:
On the upperside, the male is mostly white on the forewing and almost entirely yellow with tornal area orange on the hindwing, while the female has broader dark border on both wings and isolated squarish white spots in spaces 1b and 3 in the forewing. On the underside of both sexes, the forewing is adorned with white streaks/spots and yellow apical spots, and the hindwing is mostly yellow with dark border. This dark border in the female is distinctively broader in the hindwing especially in space 1b to 3.
Field Observations of Butterfly Behaviour:
The Orange Gull was listed as extant in Singapore by early authors, but it has not been reliably recorded until its re-discovery on Pulau Ubin in Dec 2018. Since then, observations of Orange Gull have been rather frequent on Pulau Ubin as reflected in the iNaturalist records. Most of the times, it is the males which are recorded flying around rapidly visiting flowers or puddling on wet grounds. The females are rarely seen except when ovipositing on its host plant Capparis micracantha under forest canopy. The species has clearly established itself on Pulau Ubin as evident from the multiple observations of both adults and early stages at several sites on the island.
Early Stages:
The recorded local host plants for the Orange Gull are Capparis micracantha and Crateva magna. The host plant recorded on Pulau Ubin is Capparis micracantha subsp. korthalsiana. But the caterpillars had no problem adapting to Crateva magna in captive breeding. Caterpillars of the Orange Gull feed on young leaves of both host plants, and they have the habit of resting together on the same leaf in all five instars of the larval stage. When resting, they typically choose the basal part of the leaf upperside. The entire life cycle, from oviposition to the eclosion of the adult lasts from 23 to 28 days.
Eggs of the Orange Gull are laid singly on various parts of the host plant, including on a young shoot, surface/edge of a mature leaf and stem, and even on a small thorn. The egg is spindle-shaped and standing on one end with a height of about 1.2mm and basal diameter of about 0.4mm. It has vertical ridges and numerous transverse striations. The vertical ridges end in short projections encircling the micropylar. The color of the egg is initially whitish but changes to orangy red overnight.
The egg takes about 3 days to hatch. The newly hatched has a length of about 1.9mm and a yellowish beige head capsule. Its cylindrically-shaped and translucent body is in a similar shade of yellow beige and featuring sub-dorsal, dorso-lateral and lateral rows of small tubercles running lengthwise. Each tubercle has a moderately long setae emerging from the middle of it. The end of each setae bears a tiny droplet. The newly hatched has some reddish substance within its digestive tract. This substance is slowly egested as small reddish pellets in the next few hours.
After emergence, the newly hatched only eats a small portion of the egg shell for its first meal, and soon moves on to eat the leaf lamina in the vicinity. Its body takes on a green undertone after the intake of leaf diet. As growth progresses further, numerous tiny brownish speckles appear on the sides of its body and head. In about 2 days, the caterpillar grows to a length of about 3.8-4mm before the moult to the 2nd instar.
The 2nd instar caterpillar resembles the late 1st instar caterpillar with its yellowish green body color, droplet-bearing setae and numerous lateral brownish speckles. This instar lasts about 2-3 days with the body length reaching about 7-7.5mm.
The 3rd instar caterpillar closely resembles the 2nd instar caterpillar in all body features and coloration. This instar takes about 2-3 days to complete with body length reaching about 11.5-12mm.
Again, the 4th instar caterpillar closely resembles the 3rd instar caterpillar with a few exceptions. Now the numerous whitish tubercles on the body surface are more prominent with two dorsal rows of them bearing short black setae. Moderately long whitish setae also occurring sub-spiracularly. This penultimate instar lasts about 2-3 days with body length reaching up to 24mm.
The 5th and final instar caterpillar mostly resembles the 4th instar caterpillar, but has its body and head color predominantly green. In contrast, the body color is yellowish to whitish on the side of the body below the spiracles. Those moderately long sub-spiracular whitish setae are also denser than those seen in the 4th instar. This final instar lasts for 4-5 days, and the body length reaches up to 38-40mm.
On the last day of the 5th instar, the caterpillar ceases feeding and its body gradually shortens. It wanders around and comes to rest on the surface of a leaf, usually on the upperside. Here the caterpillar spins a silk pad and a silk girdle to secure itself and then becomes immobile in a head-up pre-pupatory pose.
After about 1 day as a dormant pre-pupa, pupation takes place. The greenish pupa secures itself with the silk girdle spun in the pre-pupal stage, and with cremaster replacing claspers in its attachment to the silk pad on the leaf surface. The pupa sports a whitish thoracic dorsal ridge which is sharply raised at the mesothorax. This ridge ends in a pointed whitish cephalic horn at the anterior end. The prothorax also bears two small pointed horns on the side of the cephalic horn. Abdominal segments 2-3 are produced laterally, ending with one pointed tooth at each side of both segments. The dorsum of the prothorax and abdominal segments 2-3 are prominently whitish, giving the pupa a striking appearance. Length of pupae: 19-22mm.
After about 6 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. In the wing pad, markings on the forewing upperside become discernible and indicative of the gender of the soon-to-emerge adult. The following day, the adult Orange Gull 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.
This life history documentation of Cepora iudith was conducted in the second half of 2025 by a research group comprising Khew Sin Khoon, Lim Han Peng and Horace Tan. We thank the NParks for the permission and assistance to conduct this research (Permit No. NP/RP25-076) on "Life Stages of Butterflies in Pulau Ubin - Cepora iudith".
Text by Horace Tan, Photos by Chan Wah Choy, Hanping Lim, Michael Soh, Lumin Ong, Khew SK and Horace Tan
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