Butterfly Biodata:
Genus: Euploea Fabricius, 1807
Species: tulliolus Fabricius, 1793
Sub-species: ledereri C. & R. Felder, 1860
Wingspan of Adult Butterfly: 60-70mm
Caterpillar Local Host Plant: Malaisia scandens, (Moraceae, syn: Trophis scandens, common name: Burny Vine).
Genus: Euploea Fabricius, 1807
Species: tulliolus Fabricius, 1793
Sub-species: ledereri C. & R. Felder, 1860
Wingspan of Adult Butterfly: 60-70mm
Caterpillar Local Host Plant: Malaisia scandens, (Moraceae, syn: Trophis scandens, common name: Burny Vine).
Physical Description of Adult Butterfly:
The Dwarf Crow is the smallest member of the Euploea genus. On the upperside, the wings are reddish brown and the apical portion of the forewing is deep-blue with a few bluish or whitish discal and submarginal spots. The hindwing is unmarked in the male but the female has submarginal series of small, diffused whitish spots. The male has much rounded wings and deeply curved forewing dorsum. There is no brand in the male's forewing, but there is a raised patch of pale yellow scent scales at the front part of the cell in the hindwing. On the underside, the wings are brown with the usual Euploea white spotting along the wing margins.
The Dwarf Crow is the smallest member of the Euploea genus. On the upperside, the wings are reddish brown and the apical portion of the forewing is deep-blue with a few bluish or whitish discal and submarginal spots. The hindwing is unmarked in the male but the female has submarginal series of small, diffused whitish spots. The male has much rounded wings and deeply curved forewing dorsum. There is no brand in the male's forewing, but there is a raised patch of pale yellow scent scales at the front part of the cell in the hindwing. On the underside, the wings are brown with the usual Euploea white spotting along the wing margins.
Field Observations of Butterfly Behaviour:
Dwarf Crow was earlier assumed to be locally extinct in Singapore, but since its re-discovery in 2002 in the offshore island of Pulau Ubin, it has been regularly observed there. From time to time, the species can be rather abundent at certain localities. In its habitats, the adults have been observed visiting flowers of various weeds and cultivated plants for nectar. The males also have the habit of puddling on wet grounds for minerals.
Dwarf Crow was earlier assumed to be locally extinct in Singapore, but since its re-discovery in 2002 in the offshore island of Pulau Ubin, it has been regularly observed there. From time to time, the species can be rather abundent at certain localities. In its habitats, the adults have been observed visiting flowers of various weeds and cultivated plants for nectar. The males also have the habit of puddling on wet grounds for minerals.
Early Stages:
A video clip showing the adult and immature stages of the Dwarf Crow.
Only one local host plant, Malaisia scandens (syn: Trophis scandens, Burny Vine), has been recorded thus far. This vine is rather common in Pulau Ubin, and this is probably the main reason behind the frequent sightings of Dwarf Crow in the offshore island. Caterpillars of the Dwarf Crow mainly feed on young to immature leaves of the vine.
Eggs of the Dwarf Crow are laid singly on the underside of a leaf (typically young leaf) of the host plant. The creamy yellow eggs are tall (about 1.3mm in height) and somewhat cylindrical (diameter: about 0.85mm) with a rounded top. The egg surface is ribbed.
The egg takes about 3 days to hatch. The young caterpillar emerges by eating away part of the egg shell. The rest of the egg shell becomes the first meal for the newly hatched, which has a length of about 2.5mm. The newly hatched has a pale yellowish body and black head capsule. A pair of very short and inconspicuous protuberances can be found on the dorsum of each of the 2nd, 3rd thoracic segments and the 8th abdominal segment.
Once the newly hatched moves on to feed on the leaf lamina, its body starts to take on a green undertone. All its legs also turn conspiculously black in colour. In the final half day of the 1st instar, the body takes on a dark yellowish coloration, with the short protuberances turning dark brown at the same time. This first instar lasts for about 1.5 days with the body length doubled up to 5 mm.
The body of the 2nd instar caterpillar has yellowish brown transverse rings interspersed with whitish stripes. A whitish band runs sub-spiracularly across the body segments. Another change is the slight lengthening of the 6 tiny protuberances, each of which is dark brown in colour. There are two small black spots on the dorsum of the prothorax, and one black patch (anal plate) on the posterior end of the body. This instar lasts only 1.5 days with the body length reaching 8.5mm before the moult to the 3rd instar.
The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar with one obvious change being the proportionally longer protuberances, especially the pair present on the 2nd thoracic segment. In some specimens, two faint whitish lateral streaks appear on the black head capsule. This instar takes about 1.5 days to complete with body length reaching up to about 13.5mm.
Compared to the 3rd instar, the 4th instar caterpillar has proportionally longer protuberances which also have its color changed to reddish brown. The pair of protuberances on the 2nd thoracic segment is the longest among the three pairs present. On the body segments, the transverse white stripes have become more prominent with one stripe being broader on the dorsum of each abdominal segment. More strikingly, all yellowish brown transverse rings turn reddish as growth progresses in this instar. Small yellowish to orangy patches are also featured above the sub-spiracular white band. The black head capsule features two frontal, and oblique white stripes and an outer peripheral white ring. This instar lasts about 2.5 days with the body length reaching about 24.5mm.
The 5th instar caterpillar is largely similar to the 4th instar caterpillar except for having proportionately longer protuberances. Generally, the reddish transverse rings are broader than those in the previous instar, giving the caterpillar a more striking appearance.
The 5th instar lasts about 2.5-3 days, and the body length reaches up to 31-33mm. On the last day, the caterpillar ceases feeding, and its body becomes shortened and decolorised to a shade of pale yellowish brown. For pupation, the caterpillar typically chooses a spot on the mid-rib of a leaf underside. At this pupation site, the caterpillar spins a silk pad from which it then hangs vertically to take on the pre-pupatory pose.
Pupation takes place about 0.5 days after the caterpillar assumes the hanging posture. The
pupa has a length of about 18-19mm, and suspends itself from the silk pad with no
supporting silk girdle. Initially, the pupa is in a light shade of pale
yellowish brown, but the surface gradually takes on a silvery
glitter about a day later. The pupa is rather rotund, and has a few
tiny black spots on the dorsum.
After about 6 days of development, the pupal turns black as the development within the pupal case comes to an end. The white spots on the forewing upperside become discernible through the now translucent skin. In the following morning, the adult butterfly emerges from the pupal case, and perches nearby to expand and dry its wings before taking its first flight.
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.
- Seasonal Appearances - Featuring the Dwarf Crow (Euploea tulliolus ledereri), Khew S.K., ButterflyCircle blog, 24 Feb. 2018.
- A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2nd Edition, 2015.
No comments:
Post a Comment