The Fulvous Pied Flat (Pseudocoladenia dan dhyana)
A male Fulvous Pied Flat sunbathing on top of a leaf in the late afternoon
We kick start the Butterfly of the Month series with a species from the family Hesperiidae, or commonly referred to as Skippers. Skippers tend to fly rapidly and are often mistaken for moths. They have exceptionally large eyes and fat robust bodies. The sub-family Pyrginae, or Flats and Spread-Winged Skippers, is represented by 12 species from 8 genera in Singapore. Some are very rare and are classified Data Deficient in the latest Singapore Red Data Book, due to very few or very recent sightings and there is an element of doubt as to the species' existence in Singapore.
Fulvous Pied Flat - Male (Top) and Female (Bottom)
Our Butterfly of the Month for January 2024 is the Fulvous Pied Flat (Pseudocoladenia dan dhyana) a medium-sized species that was originally not recorded from Singapore in the early authors' reference checklists. It is hence deemed as a non-native or exotic species. However, after its discovery it has regularly been observed and hence appears to be naturalised with several colonies found in Singapore.
First spotted at the Bukit Timah Nature Reserve, the species is closely associated with forested habitats where its caterpillar host plant, Cyathula prostata (Amaranthaceae) grows in abundance. The plant is not difficult to cultivate, and where it is found, can be common. It is a low growing plant, usually seen as ground cover and spreads quite fast when it grows. The species is widely distributed, with colonies found at Upper Seletar Reservoir Park and at the forested areas beside Cleantech One in Nanyang Avenue in Jurong.
Fulvous Pied Flats feeding on various flowering plants
The common name of the Fulvous Pied Flat generally describes the species. Fulvous is an adjective that describes a dull yellowish-brown or tawny colour. Pied is an adjective that describes something that has two or more different colours usually in patches or spots. And being a member of the Pyrginae sub-family, it is a Flat that describes the behaviour of the species - usually perched with its wings spread open flat.
The Fulvous Pied Flat usually makes its appearance in the cool early hours of the morning. It can also be observed in the later part of the afternoon on hot sunny days, where it is seen to sunbathe on the top surfaces of leaves. During other times of the day, it tends to fly and perch on the undersides of leaves - a behaviour that is similar to many of the Pyrginae species.
Fulvous Pied Flat - Male (Top) Female (Bottom) - Note the forewing cell spot differences.
The upperside of the Fulvous Pied Flat is reddish brown. The two large yellow hyaline spots at the end of the forewing cell, which are conjoined to form a distinctive V-shaped spot, distinguishes the male from the female of this species. In the female the spots are much reduced and appear whitish. There are other dark brown diffused spots on the fore and hindwings.
The full life history has been successfully recorded in Singapore on the caterpillar host plant Cyathula prostata. This plant has a wide distribution and can be found in Asia, Australia, Africa and tropical America. Parts of the plant are used as food and medicines for diarrhoea, dysentery, pain-relief etc. Locally, this plant can be found in waste places, forest margins and alongside trails in the northern and western catchment reserves. All early stages of the Fulvous Pied Flat feed on the leaf lamina of the host plant and retreat to their leaf shelters between feeds. Typically, they rest in a curled-up posture within the shelter.
Text by Khew SK : Photos by Ash Foo, Khew SK, Lee Yue Teng, Richard Ong, Michael Soh, Horace Tan and Alson Teo
Life History of the Dwarf Crow (Euploea tulliolus ledereri)
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).
Upperside view of a female Dwarf Crow.
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.
Upperside view of a male Dwarf Crow.
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.
A group of Dwarf Crow seen during a time of abundance.
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.
Host plant: Malaisia scandens (Burny 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.
Far view of an egg of the Dwarf Crow laid on the underside of a young leaf of Burny Vine.
Close-up view of an egg of the Dwarf Crow.
Two views of a fully developed egg of the Dwarf Crow.
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.
Two views of a newly hatched caterpillar of the Dwarf Crow.
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.
Two views of a 1st instar caterpillar of the Dwarf Crow, length: 3.2mm.
Two views of a 1st instar caterpillar of the Dwarf Crow, length: 4.8mm.
Two views of a late 1st instar caterpillar of the Dwarf Crow, dormant prior to its moult, length: 5mm.
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.
Two views of a 2nd instar caterpillar of the Dwarf Crow, length: 8.4mm.
Two views of a late 2nd instar caterpillar of the Dwarf Crow, dormant prior to its moult.
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.
Two views of a newly moulted 3rd instar caterpillar of the Dwarf Crow.
Two views of a 3rd instar caterpillar of the Dwarf Crow, length: 13.5mm.
Two views of a late 3rd instar caterpillar of the Dwarf Crow, dormant prior to its moult.
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.
Two views of a newly moulted 4th instar caterpillar of the Dwarf Crow.
Two views of a 4th instar caterpillar of the Dwarf Crow, length: 19.5mm.
Two views of a 4th instar caterpillar of the Dwarf Crow, length: 21mm.
Two views of a late 4th instar caterpillar of the Dwarf Crow, dormant prior to its moult.
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.
Two views of a newly moulted 5th instar caterpillar of the Dwarf Crow.
Two views of a 5th instar caterpillar of the Dwarf Crow, length: 26mm.
Two views of a 5th instar caterpillar of the Dwarf Crow, length: 31mm.
Two views of a late 5th instar caterpillar of the Dwarf Crow, length: 26mm.
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.
Two views of a late 5th instar caterpillar of the Dwarf Crow, with body in the midst of decolorization.
Three views of a pre-pupatory caterpillar of the Dwarf Crow
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.
Three views of a newly formed pupa of the Dwarf Crow.
Three views of a one-day old pupa of the Dwarf Crow.
Three views of a maturing pupa of the Dwarf Crow.
Three views of a fully developed pupa of the Dwarf Crow with eclosion to occur soon.
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.
A newly eclosed Dwarf Crow hanging on to 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.
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