Butterfly Biodata:
Genus: Pseudotajuria Eliot, 1973
Species: donatana de Níceville, 1889
Subspecies: donatana de Níceville, 1889
Wingspan of Adult Butterfly: 27-29mm
Caterpillar Local Host Plant: Viscum ovalifolium (Santalaceae, common name: Oval-leaved Mistletoe).
Physical Description of Adult Butterfly:
The eyes are greenish. On the wing upperside, the male is shining blue with broad black border. The female is of a paler blue with broad black border. On the wing underside, both sexes are a rich golden yellow and unmarked on the forewing. In the hindwing, there are black tornal spots in spaces 1a and 2, edged with patches of metallic green scales. Each hindwing has a pair of white-tipped black tails at ends of veins 1b and 2.
Field Observations:
The Golden Royal (also known as the Dawnas Royal) is rare in Singapore. It was re-discovered in 2005 where a single individual was spotted in a reservior park. Since then there have been a few sightings at various places outside the nature reserve. The most recent sightings were in the Southern Ridges where a few individuals were observed feeding on the inflorescence of the Ivy Palm. The adult has also been sighted puddling at damp streambanks and footpaths at times.
Early Stages:
In Singapore, so far only one larval host plant has been identified. This plant is the Oval-leaved Mistletoe (Viscum ovalifolium ), a relatively rare parasitic plant in Singapore. On this plant, the early stages of the Golden Royal feed on the flower buds, fruits and leaves, with a strong preference for flower buds in the early few instars.
Eggs are laid singly on various parts of the host plant, such as the leaf, flower buds and fruits. At times, two eggs are oviposited close to each other. Each whitish egg is about 0.6-0.7mm in diameter. It is bun-shaped with a depressed micropylar at the pole and its entire surface covered with pits of varying sizes. It is unique in that the lower side of the egg is vertically inclined.
It takes about 3 days for the egg to hatch. The young
caterpillar consumes just enough of the egg shell to emerge. It is pale
yellowish brown in coloration, and has a length of about 1.2mm. Long setae (hairs)
run along the length of the body dorsally as well as sub-spiracularly. The head is brown in colour. The newly hatched does not bother to eat the remnant of the egg shell and proceeds to feed on flower buds present in the vicinity.
The 1st instar lasts about
2 to 2.5 days with the body length increased to about 2.1mm. Before the moult, the caterpillar typically take up its position on the surface of a leaf, and becomes immobile.
The 2nd instar caterpillar has numerous short setae covering its body surafce. Now the yellowish brown body has a strong greenish undertone. The caterpillar now features a black diamond-shaped prothoracic shield. On the sides of the prothoracic shield and the anterior part of the dorsum of the mesothorax, the body surface takes on a reddish coloration. The dorsal nectary organ on the dorsum of the 7th abdominal segment is discernible and whitish. The 2nd instar lasts about 2 days, with the body length reaching up to about 3.6mm.
The 3rd instar caterpillar resembles the 2nd instar caterpillar initially, but with a prominent and proportionately larger prothoracic shield and greater density of body setae. As it grows in this instar, the body turns increasingly greenish overall, and the dorsum of the mesothorax turns yellowish. The dorsal nectary organ at this late stage has the white coloration confined to its central part. The 3rd instar lasts about 2 days and the body length increases up to 6.5mm.
The 4th instar caterpillar resembles the late 3rd instar caterpillar in most body features/markings. One distinguishing feature is that the prothoracic shield is no longer totally black as there are whitish patches present. The dorsum of the mesothorax has become mostly yellowish. The 4th instar lasts about 2 to 3 days with the body length reaching up to 10.5-11mm.
The 5th instar caterpillar resembles the 4th instar caterpillar closely in most body features/markings. In some specimens, the white patches in the prothoracic shield are much larger and the shield becomes dominantly white. It is noteworthy that the caterpillar of the Golden Royal also closely resemble those of the Bi-spot Royal (Ancema ctesia, not extant in Singapore) although the two belong to different genera. The 5th (and final) instar lasts about 4 days with the body length reaching up to 21mm.
As it enters the pre-pupatory phase of its life cycle, the caterpillar ceases its feeding activity and wanders around for a pupation site. The pre-pupatory caterpillar settles for a spot on the upperside of a leaf with a strong preference for a leaf with curled up edges offering some degrees of concealment. At the chosen site, it spins a silk pad and a silk girdle to secure itself to the leaf.
After about 1 day of the pre-pupal period, pupation takes place. The pupa
is held via its cremaster to the silk pad on the leaf surface. It is 11 to 11.5mm in length, with the typical shape for a lycaenid pupa, albeit more rotund than usual. The pupa is yellowish green with numerous whitish to yellowish speckles. In addition, black spots in varying number appear on the dorsum of the abdomen and thorax. Some specimens could be totally void of such spots.
The pupal period is observed to be 7 days for the female and 8 days for the male. On the night before ecloson, the pupa becomes darkened in color signaling the
imminent emergence of the adult. One can now tell the sex of the soon-to-emerge butterfly from the coloration of the wing pad at this stage. The next morning the adult butterfly emerges from the mature pupa.
A female Golden Royal emerges from its pupal case.
A male Golden Royal emerges from its 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.