Butterfly Biodata:
Genus: Horaga Moore, 1881
Species: syrinx C. Felder, 1860
Subspecies: maenala Hewitson, 1869
Wingspan of Adult Butterfly: 23-26 mm
Caterpillar Local Host Plants: Melicope lunu-ankenda (Rutaceae), Clausena excavata (Rutaceae, common name: False Curry Leaf Tree), Ixonanthes icosandra (Ixonanthaceae, common name: Twenty-Man Tree), Citrus maxima (Rutaceae, common name: Pomelo), Citrus microcarpa (Rutaceae, common name: Calamansi), Ixora javanica (Rubiaceae, common name: Red Ixora).
Physical Description of Adult Butterfly:
On the upperside, the male is bright clear blue and the female is purplish blue. The forewing has a broad black border and a narrow white discal patch crossed by dark-dusted veins. On the underside, both sexes are yellowish-brown with broad post-discal white bands traversing both fore- and hindwings. Both sexes have three filamentous tails on each hindwing, at veins 1b, 2 and 3, with the one at vein 2 longest among the three.
A female Ambon Onyx perching on a twig.
A male Ambon Onyx on a leaf perch.
Another male Ambon Onyx on a leaf perch.
Field Observations:
The Ambon Onyx is moderately common in Singapore, and sightings of the adults have been made in Southern Ridges, fringe of central catchment reserve and Pulau Ubin. It has a strong rapid flight, and is often observed to sunbathe at its favourite perches.
A male Ambon Onyx puddling on a mossy patch.
A male Ambon Onyx on a leaf perch.
A female Ambon Onyx perching on an Ixora flower.
Early Stages:
Caterpillars of Ambon Onyx is polyphagous and a number of larval host plants have been identified in Singapore. They are Melicope lunu-ankenda, Clausena excavata, Ixonanthes icosandra, Ixora javanica and Citrus spp. The caterpillars of the Ambon Onyx feed on the flowers, flower buds and young leaves of these host plants, with a strong preference for the flowers and flower buds.
Local host plant 1: Melicope lunu-ankenda.
Local host plant 2: Clausena excavata.
Local host plant 3: Ixora javanica.
A mating pair of the Ambon Onyx.
Eggs are laid singly on the young shoot or the inflorescence of the host plant. Each egg resembles a bun with coarse hexagonal reticulations. It is initially pale greenish when newly laid but turns whitish as it matures. Each egg has a basal diameter of about 0.8mm.
Two views of an egg of the Ambon Onyx.
A newly hatched caterpillar of the Ambon Onyx resting next to the empty egg shell.
The egg takes about 3 days to hatch. The caterpillar nibbles away the top part of the egg shell to emerge. The newly hatched is about 1.1mm long, with a pale yellowish brown head and a pale yellowish brown body covered with long setae dorsally and laterally. As growth progresses, dorsal tubercles on the metathorax (a pair) and 1st to 7th abdominal segments (one each) become marked in reddish brown. The first instar sees the body length reaches up to 3mm, and lasts about 2.5-3 days before the moult to the next instar.
Two views of a newly hatched caterpillar of the Ambon Onyx, length: 1.2mm.
Two views of a first instar caterpillar of the Ambon Onyx feeding on Red Ixora, length: 2.1mm.
Two views of a first instar caterpillar of the Ambon Onyx feeding on the young shoot of Twenty-Man Tree, length: 2.9mm.
Two views of a first instar caterpillar of the Ambon Onyx, length: 3mm.
Two views of a late first instar caterpillar of the Ambon Onyx, dormant prior to its moult.
The second instar caterpillar is either pale yellowish green or yellowish brown in base colour. It features numerous short setae on the body surface and has a number of prominent and pointed tubercles projecting from the body surface. The 2nd instar lasts about 2.5-3 days with the body length reaches up to 5-5.2mm.
Two views of an early second instar caterpillar of the Ambon Onyx feeding on Red Ixora, length: 3.3mm.
Two views of a second instar caterpillar of the Ambon Onyx feeding on Red Ixora, length:5mm.
Two views of a second instar caterpillar of the Ambon Onyx feeding on Twenty-Man Tree, length: 5mm.
Two views of a late second instar caterpillar of the Ambon Onyx, dormant prior to its moult.
The third instar caterpillar has the same configuration of dorsal, dorso-lateral and sub-spiracular tubercles as in the 2nd instar, but they are now proportionately longer and prominent, particularly so for the ones on 2nd, 6th and 7th abdominal segments. Whitish patches adorn the basal part of the dorsal tubercles. A whitish band also run sub-spiracularly along the side of the body. The third instar lasts about 3 days and has its length reaches up to about 10 mm before the moult to the 4th (and final) instar.
Two views of a third instar caterpillar of the Ambon Onyx feeding on Red Ixora, early in this instar, length: 5.6mm.
Two views of a third instar caterpillar of the Ambon Onyx, length: 9mm.
Two views of a late third instar caterpillar of the Ambon Onyx, dormant prior to its moult.
The 4th instar caterpillar has proportionately longer dorsal, dorso-lateral and sub-spiracular tubercles then those seen in the 3rd instar. Laterally, the lateral part of the 1st, 3rd, 4th and 5th abdominal segments are suffused with reddish brown to varying extent.
Two views of a 4th instar caterpillar of the Ambon Onyx, early in this instar, length: 10mm.
Two views of a 4th instar caterpillar of the Ambon Onyx, length: 11mm.
Two views of a 4th instar caterpillar of the Ambon Onyx, with much intense reddish coloration, length: 15mm.
A green form 4th instar caterpillar of the Ambon Onyx feeding on flowers buds of Melicope lunu-ankenda.
Two views of a 4th instar caterpillar of the Ambon Onyx, length: 16mm.
Two views of a 4th instar caterpillar of the Ambon Onyx feeding on a young leaf of the Twenty-Man Tree, green form, length: 18mm.
The 4th instar lasts about 4 days with the body length reaches up to 17-18mm. On the last day, the body gradually shortens. The caterpillar stops feeding, wanders around and eventually comes to rest on a spot on the stem or a pedicel where it begins the silk spinning effort to turn it into its pupation site. Once the silk pad is done, the caterpillar secures itself to it and turns into an immobile pre-pupa.
Two views of a pre-pupa of the Ambon Onyx, on a pedicel of Red Ixora.
The pre-pupal stage of the caterpillar lasts about one day. The ensuing pupation event turns it into a yellowish green pupa with the typical shape of a lycaenid pupa. The small pupa is about 8.5-9.5mm in length. The pupa attaches itself to the stem/pedicel via its broad cremaster end. The pupal surface is mostly smooth, with only a few short protrusions appearing on the dorsum in several abdominal segments. There is a pair of small reddish dorso-lateral patches on the 1st abdominal segment, and U-shaped pale brownish markings on the 3rd to 5th abdominal segments. Small irregularly shaped whitish patches also occur on the pupal surface and on the frontal part of the wing pads. In some pupae, the rear part of the wing pads is brownish. It is not uncommon for some pupae to feature little or no markings on the pupal surface.
Two views of a pupa of the Ambon Onyx, length: 9mm.
Two views of another pupa of the Ambon Onyx, length: 8.5mm.
Two views of another pupa of the Ambon Onyx, with reduced markings present.
After six to seven days, the pupa gradually turn dark towards the end of the day, with the wing pads prominently black with a few small whitish patches embedded. Next morning, the adult butterfly emerges from the mature pupa. It rests on the pupal case or nearby stem surface to have its wings gradually expanded. A few hours later, the adult Ambon Onyx takes its first flight.
Two views of a mature pupa of the Ambon Onyx.
A female Ambon Onyx emerging from its chrysalis.
A newly eclosed male Ambon Onyx resting near its pupal case.
A newly eclosed female Ambon Onyx resting near its pupal case.
References:
I would like to express my gratitude to Hanpeng Lim and Koh Cher Hern for sharing information on the host plant and early stages of the Ambon Onyx.
Text by Horace Tan, Photos by Koh Cher Hern, Loke PF, Nelson Ong, Anthony Wong, Khew SK and Horace Tan.
On the upperside, the male is bright clear blue and the female is purplish blue. The forewing has a broad black border and a narrow white discal patch crossed by dark-dusted veins. On the underside, both sexes are yellowish-brown with broad post-discal white bands traversing both fore- and hindwings. Both sexes have three filamentous tails on each hindwing, at veins 1b, 2 and 3, with the one at vein 2 longest among the three.
Field Observations:
The Ambon Onyx is moderately common in Singapore, and sightings of the adults have been made in Southern Ridges, fringe of central catchment reserve and Pulau Ubin. It has a strong rapid flight, and is often observed to sunbathe at its favourite perches.
Early Stages:
Caterpillars of Ambon Onyx is polyphagous and a number of larval host plants have been identified in Singapore. They are Melicope lunu-ankenda, Clausena excavata, Ixonanthes icosandra, Ixora javanica and Citrus spp. The caterpillars of the Ambon Onyx feed on the flowers, flower buds and young leaves of these host plants, with a strong preference for the flowers and flower buds.
Eggs are laid singly on the young shoot or the inflorescence of the host plant. Each egg resembles a bun with coarse hexagonal reticulations. It is initially pale greenish when newly laid but turns whitish as it matures. Each egg has a basal diameter of about 0.8mm.
The egg takes about 3 days to hatch. The caterpillar nibbles away the top part of the egg shell to emerge. The newly hatched is about 1.1mm long, with a pale yellowish brown head and a pale yellowish brown body covered with long setae dorsally and laterally. As growth progresses, dorsal tubercles on the metathorax (a pair) and 1st to 7th abdominal segments (one each) become marked in reddish brown. The first instar sees the body length reaches up to 3mm, and lasts about 2.5-3 days before the moult to the next instar.
The second instar caterpillar is either pale yellowish green or yellowish brown in base colour. It features numerous short setae on the body surface and has a number of prominent and pointed tubercles projecting from the body surface. The 2nd instar lasts about 2.5-3 days with the body length reaches up to 5-5.2mm.
The third instar caterpillar has the same configuration of dorsal, dorso-lateral and sub-spiracular tubercles as in the 2nd instar, but they are now proportionately longer and prominent, particularly so for the ones on 2nd, 6th and 7th abdominal segments. Whitish patches adorn the basal part of the dorsal tubercles. A whitish band also run sub-spiracularly along the side of the body. The third instar lasts about 3 days and has its length reaches up to about 10 mm before the moult to the 4th (and final) instar.
The 4th instar caterpillar has proportionately longer dorsal, dorso-lateral and sub-spiracular tubercles then those seen in the 3rd instar. Laterally, the lateral part of the 1st, 3rd, 4th and 5th abdominal segments are suffused with reddish brown to varying extent.
The 4th instar lasts about 4 days with the body length reaches up to 17-18mm. On the last day, the body gradually shortens. The caterpillar stops feeding, wanders around and eventually comes to rest on a spot on the stem or a pedicel where it begins the silk spinning effort to turn it into its pupation site. Once the silk pad is done, the caterpillar secures itself to it and turns into an immobile pre-pupa.
The pre-pupal stage of the caterpillar lasts about one day. The ensuing pupation event turns it into a yellowish green pupa with the typical shape of a lycaenid pupa. The small pupa is about 8.5-9.5mm in length. The pupa attaches itself to the stem/pedicel via its broad cremaster end. The pupal surface is mostly smooth, with only a few short protrusions appearing on the dorsum in several abdominal segments. There is a pair of small reddish dorso-lateral patches on the 1st abdominal segment, and U-shaped pale brownish markings on the 3rd to 5th abdominal segments. Small irregularly shaped whitish patches also occur on the pupal surface and on the frontal part of the wing pads. In some pupae, the rear part of the wing pads is brownish. It is not uncommon for some pupae to feature little or no markings on the pupal surface.
After six to seven days, the pupa gradually turn dark towards the end of the day, with the wing pads prominently black with a few small whitish patches embedded. Next morning, the adult butterfly emerges from the mature pupa. It rests on the pupal case or nearby stem surface to have its wings gradually expanded. A few hours later, the adult Ambon Onyx takes its first flight.
A female Ambon Onyx emerging from its chrysalis.
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 Hanpeng Lim and Koh Cher Hern for sharing information on the host plant and early stages of the Ambon Onyx.
Text by Horace Tan, Photos by Koh Cher Hern, Loke PF, Nelson Ong, Anthony Wong, Khew SK and Horace Tan.
