Butterfly of the Month - September 2012

Butterfly of the Month - September 2012
The Acacia Blue (Surendra vivarna amisena)

The month of September blows past, bringing in the colder winds of autumn in the northern hemisphere as the year 2012 move towards its final three months. As the 9-11 (Sep 11) anniversary came and went without much incidents, the month of September 2012 featured unrest again in the Islamic world, as Muslims protested rather violently against an ill-conceived film produced by an amateurish zealot in the US who definitely wasn't using his brain (if he had one).

Elsewhere nearer in Asia, disputes erupted between China and Japan over a few little uninhabited rocks in the sea - the Senkaku Islands (to the Japanese, or Diaoyu Islands, to the Chinese). The Senkaku Islands are located in the East China Sea between Japan, the People's Republic of China, and Taiwan. The archipelago contains five uninhabited islands and three barren rocks, ranging in size from 800m² to 4.32km².



In various cities in China, protesters damaged Japanese-owned establishments and objects of Japanese origin.  Again, a senseless display of violence and destructive nature of human beings, stirred up by nationalistic fervour and challenge to a nation's sovereignity.  One can only hope that diplomacy and common sense will prevail to end such unrest, in a turbulent world that is already unstable in the face of economic crisis.

Back in Singapore, concerns of a recession looms, as indicators show some evidence of a softening economy across many sectors.  Will Singapore be able to take another storm so quickly?  Or will it be another short-lived downturn that will pass quickly? On another pressing issue, that sparked active national "conversations" it has been estimated that Singapore's population has increased to 5.31 million, and growing. That's 7,257 persons per sq km! From the Department of Statistics' site, only 61.8% of the population are Singapore citizens, with the other 38.2% non-citizens. What should Singapore's 714 sq km carrying capacity be? The jury is still out on that.

September's Flower is usually associated with the Aster. There are roughly 180 species within the genus, all but one being confined to Eurasia. The name Aster comes from the Ancient Greek word ἀστήρ (astér), meaning "star", referring to the shape of the flower head. The Aster is unique for its delicate purple colour.  Legend has it that burning the Aster leaves will keep away snakes. In French tradition it is said that placing the flowers on the grave of a dead soldier is a tribute to his bravery.

Our feature butterfly for September is the Acacia Blue (Surendra vivarna amisena).  This small Lycaenid (wingspan about 28-32mm) is not rare. It is more often encountered in the forested areas than urban Singapore, although it is quite widespread in distribution, and occurs in parks and gardens as well.  It has a rapid flight and can be quite skittish.  Females are often encountered in the vicinity of its favourite host plant, the Albizia.  

The English common name "Acacia" suggests that the butterfly has some sort of association with the Wattles (Acacia spp.).  Indeed, upon checking up on the genus Surendra, there are related species like S. quercetorum (a species that does not occur in Singapore) does feed on species of Acacia like Acacia pennata. This could have been the rationale for the origin of the name Acacia Blue, although here in Singapore, the species has thus far not been known to be associated with any Acacia plants.

Sunbathing Acacia Blues showing off their uppersides - top female; bottom male

The male Acacia Blue is deep purple-blue above, with a thick jet-black apical border on the forewing.  The female is steely blue, and generally unmarked on both wings above.  The underside is a hair brown with small and obscure dark spots and striae on both wings.  The tornal area of the hindwing has silvery-green markings.  There is a short stubby tail at vein 2 of the hindwing and another short tooth at vein 3.

This green-eyed species' caterpillars are usually found on the host plants co-existing with a species of ants.  The well camouflaged caterpillar has been successfully bred on at least three different species of Leguminosae in Singapore.  Both sexes are observed to open their wings to sunbathe at certain hours of the day, showing off their blue uppersides.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Federick Ho, Khew SK, Henry Koh, Koh CH, Loke PF, Nelson Ong, Jonathan Soong & Horace Tan

Life History of the Perak Lascar

Life History of the Perak Lascar (Pantoporia paraka paraka)

Butterfly Biodata:
Genus: Pantoporia Hübner, 1819
Species: paraka Butler, 1879
Subspecies: paraka Butler, 1879
Wingspan of Adult Butterfly: 35-45mm
Caterpillar Local Host Plants: Dalbergia candenatensis (Leguminosae), Dalbergia rostrata (Leguminosae), Cnestis palala (Connaraceae).

Physical Description of Adult Butterfly:
Above, the wings are dark brown to black with orange markings. On the forewing, there is a broad orange cell streak with two small indentations.  There are two orange submarginal lines on the forewing, one or both of which bends at  space 3.  The hindwing has a subbasal streak passing through base of cell, and a basal streak passing along costa. The dorsum of the thorax has a small yellowish green band aligned with the forewing cell streaks. Underneath, the wings have pale orange markings corresponding to those on the upperside, but generally larger, more diffuse  and edged in brown to black along some edges..These markings are set against a background in a shade of yellowish orange.

Field Observations of Butterfly Behaviour:  
This species is moderately common in Singapore.  It is more frequently found in back mangrove habitats (Sungei Buloh Wetland Reserve, Kranji nature trail, Pulau Ubin and Pulau Semakau) where its host plant,  Dalbergia candenatensis, thrives. The species can also be sighted, though less frequently, along forest trails in the nature reserve where its other host plant, Dalbergia rostrata,  is growing in small clusters on trail sides. The adults are weak flyers but are rather alert and skittish, and would quickly ascend to the tree top when alarmed. The adults have been sighted visiting flowers and puddling on wet ground, and would typically open their wings fully when perching.

Early Stages:
Of the three recorded local host plants for the Perak Lascar, two are Dalbergia species which are both relatively common in back mangrove habitats and in parts of the  nature reserve respectively. The third host plant, Cnestis palala (Connaraceae) which is relatively  rare in the nature reserve,  is also utilized by the immature stages of the Burmese Lascar.  

Local host plant #1: Dalbergia candenatensis.

Local host plant #2: Dalbergia rostrata.

Local host plant #3: Cnestis palala.

The caterpillars of the Perak Lascar feed on the young to middle-aged leaves of its host plants.  They typically feed in the open on the leaf surface, and rest on the midrib between feeds. The lamina of each leaf is usually eaten from the tip, leaving the midrib uneaten. But unlike the Athyma spp., there is no attempt to construct frass chain or frass barrier.  As in the case of Lasippa spp., the caterpillar of the Perak  Lascar in all instars has the habit of cutting rachis and petiole of the leaf it resides on and using silk threads to attach pieces of cut lamina to the exposed midrib. Its diet consists mostly of the brown and withered leaf lamina created in this process.

An early instar Perak Lascar caterpillar found on a leaf of Dalbergia rostrata in the nature reserve.

An early instar Perak Lascar caterpillar found on a leaf of Dalbergia candenatensis in Kranji nature trail.

The eggs of the Perak Lascar are laid singly at the tip of a leaf  or a budding young shoot of the host plant. The ovipositing female shares a common ovipositing routine adopted by a good number of  Nymphalidae species: After landing on a leaf and finding it suitable, the female reverses along the leaf surface, typically along the midrib, until its abdomen tip reaches the leaf tip where an egg is then deposited.

A mother Perak Lascar laying an egg at the leaf tip of a young leaf of Dalbergia rostrata.

Two views of an egg laid at a leaf tip. Diameter: 0.9mm.

The eggs are somewhat globular in shape, with surface marked with hexagonal pits and bearing spines at pit corners, giving them the appearance of minute sea-urchins. The micropylar sits atop. Freshly laid eggs are green in colour, but turning yellowish with rosy red patches when maturing. Each egg has a diameter of about 0.9mm. 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 2mm. It has a cylindrical pale greyish brown  body covered with many small tubercles and short setae. Four pairs of subdoral tubercles, found on the 2nd,  3rd thoraic segments and 2nd, 8th abdomnal segments,  are somewhat larger than the rest. The head capsule is similarly coloured but in a darker shade of brown.

Two views of a mature egg.

Two views of  a early 1st instar caterpillar, hours after it emerged from its egg., length: 2.2mm.

As the caterpillar grows, the body turns increasingly darker. The four pairs of subdorsal tubercles becomes more prominent. After reaching about 4.0mm in 2 days, the caterpillar moults to the 2nd instar.

Two views of a 1st instar caterpillar, late in this stage, length: 4mm.

The body color of the 2nd instar caterpillar is yellowish brown to reddish brown with a series of lateral oblique and inconspicuous streaks. Besides tiny tubercles covering most of its body surface, the 4 subdorsal pairs of tubercles have become longer and more spine-like with short protuberances. Furthermore, each of the two thoracic pairs of spines appear to  be connected with a slightly raised ridge between the two spines on each side. White strips are featured at the base of 8th and 9th abdominal segments. The head capsule is dark brown and dotted with a number of pale yellowish brown conical tubercles. This instar lasts about 3 days with the body length reaching about 5.5-6mm.

Two views of a 2nd instar caterpillar , length: 5.2mm.

The 3rd instar caterpillar has similar body markings as the 2nd instar  but with all  4 paris of subdorsal spines longer proportinately, and ridge connection in the two thoracic pairs more evident. A large saddle becomes apparent with a curved and tapering boundary taking shape, stretching from the base of the 2nd abdominal segment to a spot on the dorsum  of the 8th abdomnal segment between the two subdorsal spines.  This instar takes about 6-8 days to complete with body length reaching about 8-9mm.

Two views of a 3rd instar caterpillar, early in this stage, length: 6.5mm

Two views of a 3rd instar caterpillar, length: 9mm

The 4th instar caterpillar resembles the 3rd instar caterpillar closely. The oblique lateral brown streaks gain greater prominence with an increase in its shade of brown. A black lateral patch now appears  on the 6th abdominal segment, right on the boundary line of the saddle marking. The subdorsal pair of spines on the 8th abdominal segment are now the longest of all the subdoral spines, and are backward pointing as in the case for the pair on the 2nd abdominal segment.  This instar lasts about 8-9 days with the body length reaching about 12-13mm.

Two views of a newly moulted 4th instar caterpillar, length: 9.5mm.

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

A 4th instar caterpillar found on its resident leaf in a back mangrove habitat.

Except from the proportionately increase in the length/size of the body and head capsule, the 5th instar caterpillar is little changed from the 4th instar in all body markings and features.

Two views of a newly moulted 5th instar caterpillar.

Two views of a 5th instar caterpillar feeding on withered leaf lamina, late in this stage, length: 17mm.

A 5th instar caterpillar found on a leaf in the field. The right panel contains a close-up view.

The duration of the 5th instar is rather variable, ranging from 10 days to 18 days in various bred specimens. The maximum body length is just as variable, with some only reach up only 17mm  and the longest ones up to 21mm.  On the last day, the color of the body decolorises slightly for some specimens, and none at all in others.  Typically, the fully grown caterpillar ceases feeding and stays dormant for a while. Then it proceeds to the tip of the midrib of a  eaten leaf, and spins a silk pad right at the tip. The caterpillar then turns around and attaches its claspers to the silk pad. From this head-up position, it  then gradually lets loose of its foot grip and in one short instant drops down to assume the hanging pre-pupatory posture. This particular `head-up drop' procedure is only adopted by a handful of Nymphalidae species.

A Perak Lascar caterpillar going through the chores of becoming a hanging pre-pupa.

Two views of a pre-pupa of the Perak Lascar.

Pupation takes place about 0.5 to a day later. The pupa suspends itself via a cremastral attachment to the silk pad at the leaf tip. It is almost entirely dark to rusty brown in color, with the ventral side of the head region and leading edge of the wing cases in a lighter shade of brown. The abdominal segments are  bent and tapering to the thin  and narrow cremaster at its posterior end. The wing cases are rather large and broaden laterally. The dorsum of the thorax is angular and is adorned with a number of silvery spots. The head is bluntly cleft at its front edge with small pointed lateral vertices. Length of pupae: 11-12mm.

Three views of a pupa of the Perak Lascar.

A pupa of the Perak Lascar found in the field.

After about 5 days of development, the pupal turns dark as the development within the pupal case comes to an end. The orange spots and streak on the forewing upperside also become discernible. The following day, the adult butterfly emerges from the pupal case.

Three views of a mature pupa. Orange markings on the forewings are now visible.

A Perak Lascar caterpillar emerges from its pupal case.

A newly eclosed Perak Lascar hanging on to its pupal case.

Another newly eclosed Perak Lascar hanging on to its pupal case.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
• A Field Guide to the Butterflies of Singapore, Khew S K, Ink on Paper Comm. Pte. Ltd., 2010. 
• Butterflies of Thailand, Pisuth EK-Amnuay, 1st Edition, 2006.

Text by Horace Tan, Photos by Benedict Tay,  Khew SK and Horace Tan

Random Gallery - Gram Blue

Random Butterfly Gallery 
The Gram Blue (Euchrysops cnejus cnejus)

An additional shot for our random gallery this week, by our junior ButterflyCircle member, Jonathan Soong. Our 13-year old teenage talent consistently produces work that is on par with the seniors, and far exceeds that of many 'weekend photographers'.  In this shot taken last weekend, a nicely composed Gram Blue sitting on a leaf of a Leguminosae accentuates the butterfly with a clean background. The leaflet 'triplet' below the butterfly frames and underscores the subject effectively, giving an eye-pleasing composition.

The Gram Blue is moderately common and can sometimes be abundant in certain locations at times.  One of Its recorded host plants, Pueraria phaseoloides. a ground creeper, usually grows in open clearings in bright sunshine. The butterfly is active during the hotter hours of the day, and is skittish.  But it settles in the later hours of the day and stops amongst the low shrubbery and tall grasses to rest. 

Random Gallery - Leopard Lacewing

Random Butterfly Gallery
The Leopard Lacewing (Cethosia cyane)

We feature another immigrant species this week - the Leopard Lacewing (Cethosia cyane).  This species was not present in the checklists of the early researchers and appeared in the Malaysian/Singaporean territory some time in the late 90's and early 2000's.  It is common in Singapore today, and is quite widespread across various habitats.  Its preferred host plant, Passiflora foetida, is a secondary forest "weed", and grows very quickly. 

This shot of a pristine female Leopard Lacewing was taken last weekend by ButterflyCircle member Chng CK.  In the field, the brighter coloured males tend to outnumber females. 

The Atlas Moth Chronicles - Episode 3

The Atlas Moth Chronicles
Episode 3 :The Circle of Life

After sharing his meticulous documentation of the life cycle of the Atlas Moth (Attacus atlas) in Episodes 1 and 2, Dr Wee Yeow Chin returns to complete his story in this final episode of the Atlas Moth Chronicles.

Episode 2 describes the development of the caterpillars ending in eclosion. However, there was one case that did not end right. The pupating caterpillar somehow ended on the tabletop and began to lay down its silk. Not happy with this, I moved it to a branch with larger leaves (Bridellia sp.) than the original Limau Purut (Citrus hystrix). It continued to lay silk on a leaf for the next 48 hours. Because of the larger leaf size, the caterpillar wasted its silk, leaving none to cover itself. So it ended up as a “naked” pupa.

On the 12th day the caterpillar underwent a final moult, leaving a crumpled mass of old skin on the leaf. From an unattractive, dried looking caterpillar, it turned into a colourful pupa showing the various parts of the future moth. Notice the abdominal segments, folded wings, antennae, mouthparts and head. The pupa wriggled whenever disturbed. The next major change would be eclosion, where the emerging moth leaves its skin behind and crawls out of the silken case. In this particular case I would be able to follow the process unobstructed. Unfortunately I missed the crucial moment. I have only a dissected empty pupa case to show the moulted skin as well as the pupa skin inside the silken case after eclosion.

 
 

Eclosion for this naked pupa occurred at 29 days. I only realised what happened when I found a ragged moth with crumpled wings in the dish it was in. Apparently the emerging moth failed to crawl over the side of the dish and so its wings failed to expand. When I later experimented with removing the top covering of the pupa case to observe the development inside, I found the emerging moth at the edge of my computer table hanging onto a wire until its wings expanded. I had left it on a flat surface but again missed the crucial moment. It was a female and it successfully mated the following day.

The moth with the crumpled wings was left hanging from the edge of a leaf and attracted three to five male moths every night for the next seven nights. However, not a single male copulated with this strange looking female but remained around till nightfall. Was it possible that the female failed to give the necessary courtship signal? Or was it because the males failed to recognise her as a female as her wings were not expanded? In the absence of copulation, she laid about a hundred unfertilised eggs, none of which subsequently hatched.

 
 

In all instances of eclosion the emerging moth remained clinging to the pupa case until nightfall. When it was a male moth, verified by its pair of wide antennae, it would fly off sometime during the night, apparently to seek out newly emerged females. The wider and more elaborate antennae are presumed to enable it to better detect the pheromone discharged by females some distance away. However, an emerging female, with narrower antennae, always remained attached to the pupa case to await a visiting male or males.

 
 
 

Males arrived during the early morning. The first to arrive immediately attached itself to the female. A second male would sometime also cling on to the female. Latecomers simply waited nearby, to fly off the following night. Where there were two males per female, the tip of the abdomen of the first male would make connections with that of the female, thus excluding the second male. The pair remained thus for up to 11-20 hours after which they disconnect but remained attached. Then they flew off, the male probably to seek out another female and the female to lay her eggs on a host plant.

 

To collect the eggs, it would be necessary to cage the pair before they disengage. Egg laying went on for a few days under captivity, giving a total of up to 200-250 eggs per female. The female remained alive for only a few days more. A few of the males that arrived to mate with the newly emerged females failed to survive the next day, dying in the garden, their bodies disintegrating and became food for ants. They probably had visited other females previously before arriving.

 

It was noted with the second batch of 18 pupae that the first wave of emerging moths was males. Females generally emerged later. The number of days from start of pupation to eclosure was 22-23 days for males and 23-25 days for females. This would mean that caterpillars that would develop into male moths had a shorter pupa stage than potential females or they started to pupate a few days earlier. Having males eclose earlier can be a mechanism to discourage inbreeding. The males would have long gone before the females emerge. There is also the possibility of caterpillars “which eventually turn into adult females to pass through one instar more than those which develop into males," as suggested by Henry Barlow. But I failed to detect this in my caterpillars.

Text & Photos by Dr Wee Yeow Chin

Reference : Barlow, H.S., 1982. An introduction to the moths of South East Asia, Malayan Nature Society, Kuala Lumpur