26 February 2011

Butterfly of the Month - February 2011

Butterfly of the Month - February 2011
The Purple Duke (Eulaceura osteria kumana)

The short month of February is almost coming to an end, and the rainy weather that kept many a butterfly photographer in Singapore cooped up at home is also changing for sunny humid days. It will be butterfly season again soon, and members of ButterflyCircle started the year with great excitement, recording two new species to the Singapore Checklist - the Malay Dartlet and the White Banded Flat, and just as this article is being prepared, at least 2 other species have been observed!

Singapore, the Little Red Dot at the end of the Malay Peninsula, is thus far blessed with protection from natural disasters like earthquakes and typhoons. Even the 2004 tsunami, considered the deadliest tsunami in history, spared Singapore because of its location where it was shielded by Sumatra and Malaysia. The deadly tsunami, which was triggered by a 9.0 Richter scale quake which had its epicentre in the Indian Ocean near the west coast of Sumatra, killed at least 150,000 people across 11 countries and made millions homeless. And yet, Singapore was spared from the killer waves, despite its proximity to Sumatra.

The month of February, which is also the month in which I was born in 1959, is usually associated with the gemstone Amethyst. This gemstone is a purple-violet variety of quartz and ancient civilisations believed that the stone protected its owner from drunkenness! They were also believed to heal people and keep them cool-headed. Amethyst is usually associated with the colour purple and is the birthstone for the month of February.

The February born shall find,
Sincerity and peace of mind,
Freedom from passion and from care,
If they, the amethyst will wear.
- Gregorian Birthstone Poems

A male Purple Duke perches on the underside of a leaf

This month, we feature a Singapore butterfly with purple in its common name - the Purple Duke (Eulaceura osteria kumana). This species belongs to the subfamily Apaturinae, of which there are only two species found in Singapore. It is the sole representative of its genus in Singapore.

A male Purple Duke sunbathes with its wings opened flat

The male is pale purple brown above with a white discal band increasing in width from the forewing to mid-tornal area of the hindwing. The underside is tinged bluish-violet in a side light, and features ocelli in the sub-tornal area of both wings. The female is dull ochreous brown with obscure white markings on both wings. In flight the female resembles one of the females of the Euthalia or Tanaecia species.

A female Purple Duke shows the upperside of its wings as it sunbathes

The Purple Duke is a forest-dependent butterfly, and is not found outside the nature reserves of Singapore. It prefers shaded habitats in the forest understorey, and rarely leaves the safety of the forests.

The Purple Duke's typical perched pose, on the underside of a leaf. Note that the violet-blue sheen on the wings is sometimes more obvious when light from the flash hits the wings at a certain angles

The butterfly can be seasonally common, where up to half a dozen or more individuals can be seen flying around low shrubbery amongst shaded forest paths. It has a rapid flight and zips from perch to perch quickly. Both sexes of the Purple Duke have a unique habit of flying rapidly from its perch and settles on the undersides of leaves. If disturbed, it will take off and zips under another leaf to hide.

There are occasions, however, that the butterfly perches on the uppersides of leaves and occasionally open its wings flat to sunbathe, especially in the cool morning hours when the sun is just beginning to warm up the environment.

A newly-eclosed female Purple Duke opens her wings to sunbathe amongst low shrubbery

The Purple Duke's caterpillar host plant is a common forest plant, Gironniera nervosa, which is shares with another butterfly species, the Grey Sailor. The early stages of the Purple Duke has been recorded in Singapore and can be found on an earlier blog article here.

A female Purple Duke feeds on the ripened fruits of the Singapore Rhododendron

And so we end this 28-day February in the year 2011 as we look forward to the remaining months of the year with exciting new butterfly discoveries for Singapore!

Text by Khew SK : Photos by Sunny Chir, Chng CK, Federick Ho, Khew SK, Loke PF, Nelson Ong, Johnny Wee & Wong CM

23 February 2011

Re-Discovery of the White Banded Flat

Re-Discovery of the White Banded Flat
Species #298 on the Singapore Checklist

It was on one of their regular butterfly-shooting outings that ButterflyCircle members Nelson Ong and Yiming decided to take a different route to explore areas that they had not ventured before. The intention was to hopefully find something new and unrecorded.

A White Banded Flat perched on a rocky surface

Their sense of adventure and pioneering spirit was rewarded with the sighting and a few shots of a species that was extant in Singapore in the early authors' checklist, but has not been seen in recent years. What was interesting, was that they didn't just chance upon only one individual of this species, the White Banded Flat (Celaenorrhinus asmara asmara), but stumbled on a small colony of them! The skippers were observed zipping up and down a forested path, and dogfighting with other individuals of the same species, as well as other Hesperiidae species.

The shot that started all the excitement of the re-discovery of the White Banded Flat. This individual was first spotted by Yiming and Nelson

After the sighting was reported, another group of ButterflyCircle members headed for the location and observed the same behaviour in the colony of the species. At certain times of the day, the White Banded Flats were observed stopping and sunbathing on the top surfaces of leaves, almost repeating a fixed routine where they fly rapidly, and then returning to the a favourite perch to sunbathe.

A White Banded Flat checking out the flash of one of the BC members

Occasionally, they even stop on rocks in the same manner, and one even stopped on one of the photographer's camera flash, as if to check out the intruders into their territory! However, this behaviour appeared to be just for sunbathing and resting after their rapid flight. None of them were observed to be feeding on the leaves or perches, as their proboscis were not extended for feeding.

When it has had enough of sunbathing on the top surfaces of leaves, it reverts to the habit of perching on the undersides of leaves with its wings opened flat as shown in this photo

After a period of time, they reverted to the typical behaviour of the subfamily Pyrginae (Flats) whereby they stop on the undersides of leaves with their wings opened flat. Further visits and observations indicated that there was at least half a dozen or more individuals of this species in that location. However, after a period of activity and chasing each other in rapid bursts of active flight, the butterflies abruptly disappeared mysteriously altogether!

This observation is quite consistent with some species of the subfamily Pyrginae, where their active period during the day is very time-sensitive, almost like clockwork, and then beyond their magical "hour" (sometimes longer, sometimes shorter), they will mysteriously disappear suddenly, only to appear at the same time and location the following day, over a period of time.

The White Banded Flat belongs to the genus Celaenorrhinus, which occurs in the tropics of Asia, Africa and America. Some 80 species are known to exist, although only 10 are recorded in Malaysia. In the reference checklist (Ref : Corbet & Pendlebury), one species, C. asmara asmara was recorded in Singapore. However, until this recent re-discovery, the species has not been seen in Singapore over the past two decades or more.

Mr Hairy Legs! The erectile hair tuft on the hind tibia of the male of the White Banded Flat

The males of the species in the genus have erectile hair tuft on the hind tibia which gives the legs a rather hairy and unique appearance. The White Banded Flat has been described as uncommon but widely distributed in the lowlands of Malaysia. On the forewing above, the forewing cell spot is not continued above the radius and there is no white spot in cell 1b. The discal fascia is white and does not extend below vein 2. There are some obscure darker brown markings on the hindwings above.

The host plant is Clerodendrum fragrans. The caterpillar is described as stout with a short neck and a lustrous black head. It is also noteworthy that the scientific name of the species comes from the Malay word asmara which means "romance or love". Whether Butler intended the name of this species to have been derived from the Malay word when he described this species back in 1879 is a subject for further investigation.

With this re-discovery, credited to ButterflyCircle members Nelson and Yiming, the Singapore Butterfly checklist edges closer to the 300 mark as we record this as species #298.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Khew SK, Nelson Ong & Anthony Wong

References :

The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.

18 February 2011

Life History of the Psyche

Life History of the Psyche (Leptosia nina malayana)

Butterfly Biodata:
Genus: Leptosia
Hübner, 1818
Species: nina Fabricius, 1793
malayana Fruhstorfer, 1910
Wingspan of Adult Butterfly: 35-45mm
Caterpillar Local Host Plants:
Cleome rutidosperma (Capparaceae; common name: Purple Cleome, Fringed Spiderflower; synonym: C. ciliata).

Physical Description of Adult Butterfly:
The adults are small and have rounded white wings. Above, the wings are entirely white except for a black apical border and a black subapical spot on the forewing. Beneath, the wings are white in ground color, and there is a black subapical spot on the forewing as per the upperside. The entire hindwing as well as the costal border and apex of the forewing are marked with several dark striations which are highlighted in pale green shading. These green patches are usually lost in aged or weathered specimens.

Field Observations of Butterfly Behaviour:
As is the case for the entire oriental region, Psyche is relatively common and widespread in Singapore. The small and delicate adults are often seen flying incessantly in wastelands, at the fringe of nature reserves, grassy patches and even in urban and residential areas. Typically they are found in areas where its host plant, the Purplse a common weed, is growing in relative abundance. The slow and gentle flying adults are most active in sunny weather and frequently visit flowers for nectar.

Early Stages:
The only recorded local host plant, Cleome rutidosperma, is a common herbaceous weed with violet-blue to pink flowers. The caterpillars of the Psyche feed on the relatively young to middle-aged leaves and young/ tender stems. Locally, Psyche shares the same host plant with Striped Albatross and Cabbage White.

Host plant: Cleome rutodosperma.

A mating pair of the Psyche.

The eggs of the Psyche are laid singly on the host plant, typically on the underside of a leaf. The egg is spindle-shaped and standing on one end with a height of about 1.2-1.3mm, and 0.3mm in diameter. It has vertical ridges and numerous transverse striations. The vertical ridges end in low projections encircling the micropylar. The color of the egg is initially bluish green but gradually decolorises to pale yellowish green as the egg matures.

Two views of an egg of the Psyche. Left: few hours old; Right: maturing egg.

The egg takes about 2.5-3 days to hatch. The newly hatched has a length of about 1.8mm and has a whitish translucent head capsule. Its cylindrically-shaped body is whitish with yellowish green undertone. and featuring dorsal, dorso-lateral and lateral rows of small tubercles running lengthwise. Each tubercle has a long setae emerging from the middle of it. The end of each setae bears a tiny droplet.

A newly hatched caterpillar resting near its egg shell.

Two views of a 1st instar caterpillar, length: 2.3mm.

The newly hatched eats the empty egg shell for its first meal, and then moves on to eat the leaf lamina. With the intake of the leafy diet, the body takes on a green undertone, and the head capsule turns pale yellowish. The 1st instar growth is fast paced and the body length reaches about 3mm. After about 2 days in the 1st instar, the caterpillar moults to the next instar.

Two views of a late 1st Instar caterpillar hours before its moult, length: 3mm.

The 2nd instar caterpillar is yellowish green with similar setae-bearing tubercles as in the 1st instar. Besides these prominent tubercles, there are numerous tiny tubercles doting the body surface giving the cat a freckled appearance.
This instar lasts about 1.5-2 days with the body length reaching up to 4.5mm.

Two view of a 2nd instar caterpillar, length: 4.2mm

Two view of a late 2nd instar caterpillar, dormant prior to the moult.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely. Upon close examination, it is now possible observe two very short anal protrusions, but these are miniscule when compared to those seen in the Striped Albatross. This instar takes about 1.5-2 days to complete with body length reaching about 7.5mm.

Two views of a 3rd instar caterpillar, length; 5mm.

Two view of a late 3rd instar caterpillar, dormant prior to the moult.

The 4th instar retains all the features found in the 3rd instar but with a stronger green undertone in the body segments and the head capsule. Numerous moderately long and fine setae are also featured laterally. This penultimate instar lasts 1.5-2 days with body length reaching about 10mm.

Two views of a 4th instar caterpillar, length: 9mm.

Two views of a late 4th instar caterpillar, dormant prior to its moult.

The 5th and final instar caterpillar resembles the 4th instar caterpillar initially. The many shallow tubercles dotting the body surface are now darker in contrast to the ground color, giving the body a speckled appearance. The green head capsule also carries a fair number of conical tubercles with short setae emerging from most of them. As the growth progresses, the body takes on a white dusted appearance, particularly so spiracularly. The 5th instar lasts for 2.5-3.0 days, and the body length reaches up to 20-21mm.

Two views of a 5th instar caterpillar, early in this stage, length: 11mm.

Two views of a 5th instar caterpillar, late in this stage, length: 19mm.

A frontal view of a 5th instar caterpillar.

On the last day of the 5th instar, the body of the caterpillar shortens and changes to a bright green shade. It ceases feeding and comes to rest on the underside of the stem/stalk of the host plant . Here the caterpillar spins a silk pad and a silk girdle to secure itself and then becomes immobile in a cradled pre-pupatory pose.

A pre-pupatory larva of the Psyche.

Pupation takes place about 0.5 day later. The green pupa secures itself with the same silk girdle as in the pre-pupal stage. It has a very short but pointed cephalic horn, a slight dorsal protrusion, and a large wing case tapering into a keel. There are yellowish streaks occurring in the wing case and laterally. Length of pupae: 13.5-14.5mm.

Two views of a pupa of tje Psyche.

A mature pupa of the Psyche showing the prominent sub-apical spot and dark apical border on the forewing.

After about 4.5-5 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The white forewing upperside and its dark markings become discernible as a result. The following day, the adult butterfly emerges from the pupal case.

A newly eclosed Psyche drying its wings on its pupal case.

  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
  • Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006.
Text by Horace Tan, Photos by P F Loke, C K Chng, Anthony Wong, Khew SK and Horace Tan