24 February 2008

Life History of the Baron

Life History of The Baron (Euthalia aconthea gurda)

A male Baron basks in the early morning sunshine

A female Baron foraging on damp ground on rotting fruit

Butterfly Biodata :
Genus : Euthalia Hubner, 1819
Species : aconthea Fruhstorfer, 1906
Subspecies : gurda Fruhstorfer, 1906
Wingspan of Adult Butterfly : 70mm
Caterpillar Host Plant : Mangifera indica

Physical Description of Adult Butterfly : The wings are dark brown above with a broad but obscure post-discal band on both wings. A few small white spots define the inner edge of this band. The spots are larger and most distinct in the female than the male. The underside is a paler brown than the upperside. The proboscis of this species is a bright yellow-green.

Field Observations of Butterfly Behaviour : The Baron is relatively common and is often seen in urban parks and gardens. The species is also observed in residential estates where its preferred host plant, the Mango, is cultivated. As the Mango tree is a favourite fruit tree found in many gardens, the Baron is often attracted to these urban areas. It is a flighty butterfly, and a strong flyer, alert and difficult to photograph. Both males and females can sometimes be found feeding on overripe fruits.

Host plant of the Baron - Mangifera indica

Early Stages : The eggs are laid singly, usually on the undersides of the broad leaves of the host plant. The appearance of the egg is very similar to its related species in the genera of Tanaecia and Lexias, being dome-like in shape, about 2mm in diameter, and covered with hexagonal segments from which whitish hair-like protuberances emerge.

"Spiky" green egg of the Baron

After about 3-4 days, the 1st instar caterpillar emerges, eating the eggshell as its first meal. The caterpillar is yellow in colour, and sports white-edged black spines from its body. It grows to about 4mm long, before moulting into its 2nd instar.

1st instar caterpillar of the Baron

The 2nd instar caterpillar has complex branched spines and is predominantly green, with a light yellow dorsal stripe, edged with purple-brown spots, corresponding with the base of the spines.

2nd instar caterpillar of the Baron with its branched spines

The 3rd instar caterpillar is similar in appearance to the 2nd instar, but the spines have grown much longer. It feeds on the younger leaves of its host plant, and reaches about 16mm before moulting again.

3rd instar caterpillar

The 4th instar caterpillar reaches a length of about 22mm and its branched spines make it appear to be much larger than it actually is. When resting on the mid-rib of its host plant, the branched spines give the caterpillar some measure of camouflage from predators.

4th instar caterpillar reaching a length of 22 mm

The 5th instar caterpillar is medium green, and the yellowish-white dorsal stripe loses the earlier purple-brown spots along the edge of the stripe. The branched spines appear almost like a bird's feather, with the secondary spines arranged neatly perpendicular to the main spine. It reaches a mature length of about 45mm before shortening and adopting its pre-pupation pose.

Final instar caterpillar with its prominent yellowish-white dorsal stripe

Pupation takes place on the underside of a leaf of the host plant, with the cremaster firmly attached to the mid-rib of the leaf. The light green pupa has a series of brownish spots arranged symmetrically. The pupa of the Baron appears very similar to the related species in the genus, and also the related Tanaecia and Lexias species.

Two views of the Baron's pupa

The adult butterfly ecloses in the early morning hours and stays for about an hour as it dries its wings, before taking off to feed, find a mate and continue the circle of life and propagation of the next generation.

Newly eclosed female Baron showing the undersides of its wings

Newly eclosed female Baron showing the uppersides of its wings

Text by Khew SK ; Photos by Goh LC and Khew SK

18 February 2008

A new Riodinidae species for Singapore?

Is there a new Riodinidae species in Singapore?

Some time back in mid 2004, a small colony of what was first thought to be the Malayan Plum Judy (Abisara saturata kausambioides) was discovered at several locations at Singapore's urban hill parks known as the "Three Ridges".

A side shot of the mystery Abisara sp.

After taking many shots of the species, ButterflyCircle member Sunny Chir noticed that the behaviour of the individuals of this species to be rather unique. As the individuals spotted had a much stronger flight and engaged in "dog-fighting" activity - quite uncharacteristic of the behaviour of females of the Malayan Plum Judy, which these individuals resemble, Sunny continued to observe their behaviour over a period of several months, and highlighted the possibility of a different Abisara species to me.

The mystery Abisara with half-opened wings, perched on a leaf

That initial "gut-feeling" resulted in a long period of observing this species in their natural habitat - the times during which the species is most active, and their frolicking behaviour when two or three other individuals of the species were around in the same place. Thus far, no mating pairs were observed yet.

The mystery Abisara with half opened wings. In a side light, the upper wings show a purple-blue sheen.

Upon closer scrutiny of the photos taken, and by a process of elimination, we came to a tentative conclusion that this species may not be the Malayan Plum Judy (Abisara saturata kausambioides).

Taking reference from Corbet & Pendlebury's "Butterflies of the Malay Peninsula" 4th Edition, in the key for separation of the three extant Abisara species in Singapore we have :

Abisara savitri - Upperside paler, more reddish brown; forewing with inner band diffuse, sullied and from beyond mid-costa to the dorsum before the tornus. Hindwing with a long, white-tipped tail at vein 4.

Abisara geza - Underside of forewing inner postdiscal fascia bent basad above vein 4. Underside of hindwing discal band dislocated at vein 4. Male upperside with ovate paler subapical area on forewing and submarginal spots in spaces 1b, 4 and 5 of the hindwing.

Abisara saturata - Underside of hindwing discal band not dislocated, but may be angled at vein 4. Male upperside dark crimson brown and unmarked.

Male and Female Abisara saturata kausambioides

The first Abisara species - A. savitri can be eliminated due to its very distinct and different appearance from the other two species.

Hence, the unknown species :
  • cannot be Abisara geza as the hindwing discal band is not dislocated at vein 4.
  • cannot be a male Abisara saturata as the males of A. saturata are distinctly difference in appearance.
  • is not a female A. saturata as all the shots taken of this species so far, show clearly that it uses only 4 legs for walking, and this is consistent with the genus that the adult forelegs are non-functional in the male, but functional in the female.
  • is not likely to be female A. saturata due to the observation of the individuals' more robust and speedier flight, as well as "dog-fighting" behaviour - usually typical of males of this genus.

More views of the unknown Abisara sp

So the conclusion up to this point would be that this is a :
  • male specimen of an unknown Abisara sp.
  • is not an Abisara geza as it does not have the dislocated discal band at vein 4 of the hindwing
  • is not a male Abisara saturata as that species' male is distinctly marked.
So what species is this?

Voucher specimens captured of this species suggest that, from the visual inspection of the end of the abdomen of the specimens, that these individuals are males. These specimens have been sent to expert lepidopterists in Japan and Malaysia for a full-fledged dissection to ascertain the identity of this species. We are waiting patiently for the conclusion of these experts. A journal paper has been prepared to this effect, for the purpose of recording this strange and unknown Abisara as well as other discoveries by ButterflyCircle members.

A possible ID of this species flying around the hilltops of Singapore's urban parks could be Abisara kausambi kausambi. The characteristic of "Underside of forewing inner postdiscal fascia straight" and "Male upperside forewing with narrow, obscure, paler subapical area" seems to suggest that this mystery Riodinid matches the description of Abisara kausambi kausambi. However, as this species has not been recorded in Singapore by the early authors, the ID of this species remains a mystery for the time being.

Could our mystery Riodinid be Abisara kausambi? Could it be an endemic sub-species which is hitherto unrecorded in Singapore? Or perhaps a totally new Abisara species which is not even recorded in the region?

Whilst the status of this species remains uncertain in Singapore, and we wait in anticipation for the experts' advice, we would like to place on record this observation which was first made by Sunny Chir.

Who am I???

Text by Khew SK ; Photos by Khew SK, Sunny Chir, Tan CP

16 February 2008

Life History of the Suffused Flash

Life History of the Suffused Flash (Rapala suffusa barthema)

Butterfly of the Month - February 2008

The Common Red Flash (Rapala iarbus iarbus)

In the spirit of the Lunar New Year celebrations, bright red is always an auspicious colour to start off the Year of the Rat 2008. Our feature butterfly this month is a small but speedy butterfly - the Common Red Flash.

The red colours of the upperside of the male of this species gives the common name to the butterfly. The wings are red with black margins in the males, whilst the females are a drab coppery brown. The underside is light grey with darker post-discal lines which are white-edged. There is a black tornal spot on the hindwing, which is orange-crowned. The tornal lobe is covered with bluish scaling. Both the males and females have a white-tipped black tail at vein 2 of the hindwings. The species has large jet-black eyes and black-and-white banded legs.

The Common Red Flash is not very rare, and where it occurs, several individuals are often seen together. In the early morning hours and also in the late afternoons on sunny days, the males can be seen frolicking amongst forested areas where they stop to open their wings to sunbathe. During other times of the day, they appear to prefer to stop with their wings folded shut. Feeding time is usually in the mornings where common wildflowers are the favoured nectaring plants.

As with the other species of the Rapala the Common Red Flash is a fast flyer, zipping from perch to perch with blazing speeds (and hence probably the name 'Flash'). The caterpillars of this species are known to feed on young shoots of the Rambutan (Nephelium lappaceum) and the Singapore Rhododendron (Melastoma malabathricum), where it feeds on the ripening seed pods.

The Common Red Flash can be found within the nature reserves in Singapore, as well as on the offshore island of Pulau Ubin, where it is sometimes common in open sunny areas where wildflowers bloom in abundance. They often stop to rest with their wings closed shut on their favourite perches in the undergrowth.

Text by Khew SK ; Photos by Sunny Chir

10 February 2008

A New Lycaenidae species for Singapore!

ButterflyCircle finds a new Lycaenidae species in Singapore!

Some time back, in 2004, ButterflyCircle member Federick Ho shot a small Lycaenid which had our group wondering what whether it was an aberration of one of our local species, and we filed it in our UFO (Unidentified Flying Object) folder and forgot about it, as it did not appear to match anything in the books for any species flying in the South East Asian region.

In Feb 2005, another record shot of this strange Lycaenid was again taken by Federick, and this time, it did not appear to be an aberration. Internet searches turned up some similar looking species from the Australian region, but it did not appear that it would be possible for a small butterfly to migrate all the way from down under.

Then again in Nov 2006, another of our hardworking ButterflyCircle members, Horace Tan, shot this strange looking butterfly at one of our urban parks.

Finally, on Chinese New Year's Day, the Butterfly Fairy smiled on Federick Ho once again, but this time, besides being able to shoot the species again, he and Tan BJ sighted a small colony of this species, proving that it was not a wayward migrant or a one-off stowaway species that somehow got to Singapore. This had the group's members all excited, and on a weekend outing, we saw no less than half a dozen individuals - both males and females, flying around a flowering bush.

With the superior skills of our group of accomplished butterfly photographers from ButterflyCircle, the hitherto unknown species was finally recorded with clarity and sharpness, confirming what Federick and Horace shot earlier was not a phantom butterfly!

Internet searches found an Australian species of Nacaduba. This species, known as the Two Spotted Line Blue (Nacaduba biocellata) and the descriptions from several Australian websites, matched the UFO that we found in Singapore.

Description of the Two Spotted Line Blue : Male - upperside lilac with base dark blue ; Female - upperside dull brown with basal area variably suffused with blue. Underside pale brown with a series of dark brown spots and bands narrowly edged with brown and white. Each hindwing has two black subtornal spots with iridescent green scales and inwardly ringed with pale yellow brown.

The species is described as common and sometimes abundant in Australia, where its host plants are various species of Acacia. In Singapore, where the invasive Acacia auriculiformis - Earleaf Acacia, or the Northern Black Wattle or the Australian Wattle, grow wild, it is likely that the Two Spotted Line Blue has also adapted to feed on this species of Acacia. Indeed, at the location where this colony was found, there are a few Acacia trees nearby and the butterflies were seen to fly up towards the tree at times.

Given the physical appearance of this species, it is definitely one that has not been recorded in Singapore before. How it was able to 'migrate' this far from Australia is anybody's guess. But it is likely that human agency is involved, rather than natural migration. The species is therefore added to the Singapore Butterfly Checklist with the tentative name of Two Spotted Line Blue (Nacaduba biocellata) whilst further checks are being made with experts in the field - particularly the Australian lepidopterists.

Text by Khew SK ; Photos by Khew SK, Sunny Chir, Tan BJ, Sum CM, Federick Ho and Horace Tan

02 February 2008

Butterfly Photography - Shooting the Eclosion of a Butterfly

Shooting the Eclosion of a Butterfly

For most butterfly photographers, shooting the sequence of the 'hatching' of an adult butterfly as it emerges from its pupa at the culmination metamorphosis, is something extremely difficult and and requires a lot of patience, but it is nevertheless very rewarding.

The correct terminology of a butterfly 'hatching' from its pupal case is eclosion*.

*Eclosion: The emergence of an adult insect from its pupal case, or the hatching of an insect larva from an egg. From the French éclosion, from éclore, to open.

Bobby Mun, a member of ButterflyCircle, demonstrates his skill and immense patience in shooting eclosion sequence shots of a number of butterfly species.

Shooting the Eclosion

Watching the butterfly cracking open its pupal case, climbing out and then pumping "blood" (the correct term for insect "blood" is haemolymph) into its wing veins as the crumpled wings expand into their final shape for flight, is fascinating. The process that traces the transformation of a leaf-munching caterpillar into a pupa which then ecloses into a beautiful nectar-drinking butterfly is one of the wonders of Nature.

Photographing the eclosion sequence requires a fair bit of understanding of the butterfly's early stages, and preparing the equipment and location for the final shoot. The pupa, which is usually firmly attached to its perch, can be set up against an appropriate background. The photographic equipment need not be anything elaborate, other than the camera, a dedicated macro lens, and a flash unit, all mounted on a tripod for stability.

Most species' pupae change colour and appear semi-transparent on the night before eclosion. Very often, the wing patterns are visible through the semi-transparent pupal shell. Butterflies, in general, eclose during the early morning hours, which can range between 5 am to 11 am. There are even some species which eclose in the late afternoon. Hence, an understanding of the biology of the species of butterfly being photographed, would reduce the frustration of waiting in vain for an eclosion which happens the moment you take a lunch break!

Once the equipment and the setting is prepared and ready, the photographer requires nothing else but to wait for the eclosion to happen. This is easier said than done, as one would require the "patience of a Saint ; and the luck of the Devil" to succeed with a good series of the eclosion sequence.

Typically, the eclosion process takes only 3-5 minutes (for some species, even shorter!), from the time the butterfly cracks itself out of the pupal shell and clamber out to hold on to a suitable perch from which it can settle into position to pump its haemolymph to expand its wings. The process of drying its wings before it is ready for its maiden flight can take a couple of hours or more, depending on the prevalent conditions of the location at which the butterfly ecloses.

Text by Khew SK ; Photos and Layout by Bobby Mun