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 Biodata :
Genus : Rapala Moore, 1881
Species : suffusa Moore, 1879
Subspecies : barthema Distant, 1885
Wingspan of Adult Butterfly : 35mm
Caterpillar Host Plants : Talipariti tiliaceum (Sea Hibiscus), Falcataria moluccana (Albizia)

Physical Description of Adult Butterfly :
Above, the female is entirely dull brown whereas the male is brownish red with forewing border diffuse and shot with purple in a side light. The underside of the male is ochreous to pale buff brown, and the underside of the female is distinctively yellow. The markings on the undersides are typical that of Rapala spp, with cell-end bars on both wings, and brown postdiscal lines edged with white on the sides nearer to the termen. The hindwing carries a white-tipped tail with a tornal lobe between veins 1a and 1b.

Field Observations of Butterfly Behaviour :This species is common in coastal areas such as Sungei Buloh Wetland Reserve where the host plant Talipariti tiliaceum (Sea Hibiscus) is common. In sunny weather, the adults can be seen flying around the host plants and taking nectar from flowering plants in the vicinity. Typical of Rapala spp., the adults are strong and rapid flyers, darting around from one perch to another at high speeds.

Female Suffused Flash with abdomen curved to oviposit on the leaf underside

Early Stages :
In one field observation, a female adult was found to oviposit on the leaf underside and a seed pod of Asystasia intrusa. A single egg was laid each time. However, A. intrusa is not the host plant for Suffused Flash. At that location, A. intrusa grows in abundance in the shade of the actual host plant Talipariti tiliaceum.

Each egg is green in colour, small (about 0.5mm in diameter) and circular with a slightly depressed micropylar. The newly hatched caterpillars have to find their way to the host plant nearby. In a home-breeding environment, the caterpillars have no problem accepting leaves of Falcataria moluccana as alternative food source.

Two views of the same egg

After 3 days, the caterpillar hatches from the mature egg. The tiny young larva only eats parts of egg shell as it makes its exit.

Mature egg (above) and empty egg shell (below)

The newly hatched caterpillar is about 1mm in length. The 1st instar caterpillar is yellowish in base colour and has a faint dorsal line. Light brown patches are visible on the 1st, 6th to 8th abdominal segments. Rows of fine-line setae are found along the side of body. It grows to about 2mm before the moult to 2nd instar . Number of days in 1st instar : 3.

1st instar caterpillar

The 2nd instar caterpillar has dark brown patches in the thoracic segments, as well as in the1st, 6th-8th abdominal segments. There are also two brown spots on the anal plate. From above, the 7th to 10th segments appear to have fused together to form a saucer-like structure. The body length reaches about 4mm before the moult to 3rd instar. Number of days in 2nd instar : 3.

2nd Instar caterpillar

The hair-like setae in the first 2 instars give way to paddle-like setae in the 3rd instar. These paddle-like setae are mostly black, remaining ones being light brown or colourless. Brown sub-dorsal and sub-spiracular bands are also visible along the side of the body. The saucer-like structure at the tail segments is now more prominent. The caterpillar grows to about 8mm before the next moult. Number of days in 3rd instar : 3.

3rd Instar caterpillar

The 4th instar caterpillar carries similar markings as in 3rd instar but the sub-dorsal band has become dark brown and more striking. The caterpillar reaches a length of about 15mm before it moults again. Number of days in 4th instar : 4.

4th Instar caterpillar

The 5th and final instar caterpillar is much bigger with increases in both body length and width. It has similar markings as in the previous two instars. It reaches about a maximum length of 20mm before turning reddish brown and its body shrunk in preparation for the next stage. Number of days in 5th instar : 6.

5th Instar caterpillar

About 19 days of larval growth, the caterpillar ceases its feeding activity and its body colour becomes reddish brown. At the same time its body length has shrunk to about 12-13mm. The caterpillar then goes into the pre-pupation stage for one day.

Two views of a preparatory pupa

The pupa has a shape typical of most lycaenid species with a length of 11-12mm. It is bright brown with numerous small black spots/patches. The wing pads are more yellowish in ground colour. After 8 days, the pupal matures and its shell becomes transparent revealing markings on the forewing upperside. Finally, the adult butterfly emerges in early afternoon on the next day.

Two views of a pupa

Mature pupa of a male

A newly eclosed male still drying its wings

A newly eclosed male Suffused Flash ready to take flight

A noteworthy point is that the appearance of early stages of R. suffusa is very different from those of other Rapala species such as R. pheretima, R. manea, R.nissa and R. dioetas recorded thus far in the literature. Two distinguishing features are the paddle-like setae and the saucer-like structure which appear in R. suffusa but not in other above-mentioned Rapala species. Instead of paddle-like setae, these other Rapala species have short fleshy tubercles running along the sub-dorsal and sub-spiracular lines.

A close-up on the tail-end of 5th instar caterpillar of R. suffusa

A 3rd instar caterpillar of R. suffusa being attended by ants on the Sea Hibiscus leaf

Host plant: Sea Hibiscus (Hibiscus tiliaceus)

Text & Photos by Horace Tan

References :

  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
  • The Butterflies of Hong Kong, M. Bascombe, G. Johnston, F. Bascombe, Princeton University Press, 1999

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