Butterfly of the Month - April 2012

Butterfly of the Month - April 2012
The Chocolate Grass Yellow (Eurema sari sodalis)

All too soon, the fourth month of 2012 will be over.  In a few days, we will be looking towards the month of May, and most of the working population of Singapore look eagerly forward in anticipation of the public holiday on 1 May, which is Labour Day.  The wet weather from last month has not yet changed much, and Singapore has been receiving above average rainfall in April according to the meteorological information from the National Environment Agency in Singapore.  

On the work front, a momentous event happened just around 8:30pm last evening.  The company that I work for, officially changed hands from the Australians to the Chinese. At a rather quiet and private event between the two parties a small group of 10 of us partook in the little ceremony that will change the lives of my fellow employees and our future outlook.  After 7 years of 'colonialist rule', this Singapore company moves back into the hands of an Asian owner.  Hopefully, it will mean better prospects for all our staff.

The world acknowledges that Asia, and in particular China, will be the engine of economic growth in the coming years.  There will be much to do in this region, and a whole spectrum of challenges to face.  The global economy is swinging more like a rapid-beat metronome rather than a slow pendulum.  Changes will come fast and furious, and businesses have to be agile on their feet to face daily trials.  

As spring makes its way towards summer in the Northern hemisphere, flowers awaken from their cold slumber and add colour to the world of nature.  This flower of the month for April is traditionally accepted to be the Daisy (Bellis perennis).  The Daisy is actually an herb which symbolizes innocence, stability, sympathy, youth and cheerfulness.  In certain cultures the flower also signifies departure and goodbye  (a rather apt symbolism for the current situation at my workplace).  The common colour of the flower is typically white or yellow, but there are hybrids that comes in various colours and shades in between.  

This month, we feature another butterfly with the word "Chocolate" in its common name, after our March's feature butterfly.   Another Pierid, this month's Butterfly of the Month is the Chocolate Grass Yellow (Eurema sari sodalis).  One of six members of the genus Eurema, this small and usually actively flying yellow butterfly is relatively common in Singapore.  Like the other members of its genus, it can be seasonally common.

The Chocolate Grass Yellow's distinct dark brown apex on the forewing beneath instantly sets it apart from its closely-related cousins.  The upperside of the species is a bright lemon yellow with black marginal borders on both the fore and hindwings.  

Another characteristic feature that distinguishes it from the other species amongst the Grass Yellows is the single cell spot on the underside of the forewing.  Earlier articles on this blog describe the key features of the Eurema species in Singapore.  

The Chocolate Grass Yellow is quite common, and is widespread in distribution across Singapore.  It can be found deep in the nature reserves as well as in urban parks and gardens.  Like the other Grass Yellow species, it usually flies restlessly and erratically in search of food.  Photographing this species can be quite challenging at it is active and skittish.

Males of the Chocolate Grass Yellow are regularly observed puddling at damp sandbanks near streams, and muddy forest footpaths.  When puddling they can remain distracted and allow an observer to approach them for a closer look.  Watch closely at the puddling butterfly when the opportunity presents itself, and observe how it excretes fluids whilst it feeds.  This videoclip below, taken by ButterflyCircle member Loke PF, shows the process of feeding and excreting in a Chocolate Grass Yellow.



The female Chocolate Grass Yellow is typically rarer and may be found feeding at flowering plants.  On the upperside, females have broader black marginal borders where the hindwing border is thicker and inwardly diffuse.  The wings of the females are usually also more rounded when compared to the males. 

The species is a fair-weather butterfly, and normally encountered on bright sunny days rather than on overcast days.   The species can be seasonally common and a number of individuals may be encountered puddling at the same spot.  It is always amazing to see so many individuals of the same species feeding together, and then taking off in a cloud of yellow as one approaches them.  

So we bid farewell to the month of April 2012, and look forward to the remaining eight months of the year as we move closer towards the prophetic 12 Dec 2012 with curiousity and for some, even with a bit of trepidation.  For the rest of us, however, life goes on..

Text by Khew SK : Video by Loke PF : Photos by James Chia, Sunny Chir, Goh LC, Federick Ho, Khew SK, Koh CH, Lim WY & Benjamin Yam

Random Gallery - The Brown Awl

Random Butterfly Gallery
The Brown Awl (Badamia exclamationis)

This week's random butterfly was a newly-eclosed individual of the Brown Awl (Badamia exclamationis) shot by veteran ButterflyCircle member, Sunny Chir.  His excellent shot of the Brown Awl on a colourful flower won him various accolades in nature and photography online websites including Image of the Week at NatureScapes.Net and Photo of the Month at Nature Photographic Society Singapore. 

A Trio of Rarities

A Trio of Rarities
Recent Observations of Rare Butterfly Species

The months of March and April 2012 experienced rather unpredictable weather patterns with abnormally heavy rains inundating various parts of Singapore on many days of the months, and then alternating with hot sunny and humid days. These months usually coincide with the beginning of the butterfly season in SouthEast Asia, and generally where more butterflies are sighted, and in larger numbers.

However, the heavy monsoon rains may have somewhat dampened the local butterfly season. It was therefore surprising that ButterflyCircle members managed to encounter three species that are classified "Very Rare" in the 2010 "A Field Guide to the Butterflies of Singapore" book.

#1 : The White Tipped Baron (Euthalia merta merta)

The first encounter was by ButterflyCircle member Federick Ho. He was on his weekend butterfly photography outing on 17 Mar 2012 at Upper Peirce Reservoir Park. He was exploring the usual tracks in the forested areas of the nature reserves when he spotted something unusual. The puddling butterfly was foraging amongst some leaf litter on the forest floor.

Upon closer examination, and after taking shots of the upper and under sides of the butterfly, it was identified as a White Tipped Baron (Euthalia merta merta). This rare Nymphalinae, particularly the female of this species, was last seen by ButterflyCircle members on 31 Jul 2005! It was then recorded as the 286th species in the Singapore Butterfly Checklist.

It was a good record of this very rare forest species after nearly seven years! It is also great that we know that this species continues to thrive and survive in our forests although very rarely spotted. The males of the White Tipped Baron resembles the Malay Baron and the Baron, and has also been seen infrequently, but this is only the 2nd observation of the female after a long absence.

#2 : The Banded Royal (Rachana jalindra burbona)

The 2nd rarity to be observed was on the afternoon of 3 April 2012. Teenaged ButterflyCircle member Jerome Chua decided to take a venture into the nearby forested area near his home to photograph butterflies after school. However, the butterfly activity was low, he left and was heading home along the edge of the forests, when he spotted a butterfly that he had not seen before.

The butterfly was moderately docile, but wary and skittish of movements around it. After spending nearly an hour tracking and allowing the butterfly to be used to his presence, Jerome managed to take a few shots of the butterfly. It turned out to be a pristine specimen of the very rare Banded Royal (Rachana jalindra burbona).

A field shot of this species was first photographed by ButterflyCircle Janet Hong back on 15 Jan 2006 and recorded as species #272 on the Singapore checklist. There were several subsequent encounters of this species in various areas close to the Central Catchment Area. However, the butterfly is still rare and skittish, and not often encountered.

#3 : The Malayan Crow (Euploea camaralzeman malayica)

The last of the trio of rarities encountered in the past two months, is the large and black Malayan Crow (Euploea camaralzeman malayica). This Crow is described to be the 2nd largest of the genus in Malaysia and Singapore after the King Crow. It is very rare, and the first confirmed encounter of this species was a female voucher specimen taken near Upper Peirce Reservoir Park on 22 Feb 1998, during an NParks biodiversity survey. It was feeding at the flowers of a Syzygium tree.

Hence it has been over fourteen years since the last reliable observation of this very rare species was made. This recent observation was in the forests of the Dairy Farm Nature Park, where this male was seen resting on a leaf in the shade, just after 10am. It took off quickly as I approached it for a closer look. Repeated searches of the area on subsequent days were in vain, as the species was not seen again.

It is always a wonder, how rare species appear in the most unexpected places, then disappear for years before the next individual is seen again. Are the forested areas in Singapore large enough for them to hide for so long? Or are they migratory, and appear seasonally? Or perhaps the people who encounter them were just fortunate to be at the right place at the right time?

We'll never know for sure. But that's what makes butterfly-watching interesting and full of surprises. Who knows, just round the corner, at the next flowering bush, is a butterfly species that is new to Singapore, waiting to be discovered!

Text by Khew SK : Photos by Sunny Chir, Jerome Chua, Federick Ho, Janet Hong & Khew SK

Random Gallery - The Pale Mottle

Random Butterfly Gallery
04 - The Pale Mottle (Logania marmorata damis)

This week's random butterfly is the Pale Mottle (Logania marmorata damis) which belongs to the group of butterflies known as The Harvesters (Subfamily : Miletinae). The caterpillars of this family are carnivorous and feed on aphids, mealy bugs, coccids, ant larvae and so on. The butterfly often flies restlessly for long periods. This opportunistic shot of a resting Pale Mottle was taken by Anthony Wong whilst out on his weekend outing at the Zhenghua Park Connector.

Life History of the Striped Blue Crow

Life History of the Striped Blue Crow (Euploea mulciber mulciber)

Butterfly Biodata:
Genus: Euploea Fabricius, 1807
Species: mulciber Cramer, 1777
Subspecies: mulciber Cramer, 1777
Wingspan of Adult Butterfly: 80-90mm
Caterpillar Local Host Plants:  Calotropis gigantea (Asclepiadaceae, common name: Giant Milkweed), Gymnanthera oblonga (Apocynaceae, common name: Sea Rubber Vine), Nerium oleander (Apocynaceae, common name: Oleander), and various members of the Ficus genus including Ficus microcarpa (Moraceae, common name: Chinese Banyan), F. grossularioides (common name: White-leafed Fig) and F. lamponga.

A female Striped Blue Crow  visiting a flower of Bidens alba.

Another female  Striped Blue Crow visiting a cluster of Lantana flowers.

A sunbathing male Striped Blue Crow displaying its upperside.

Physical Description of Adult Butterfly:
Above, the male is bright blue in the forewing with diffuse white spots in the distal half; while the female is blue with embedded white spots in the distal half of the forewing and several white spots and streaks in the brown basal half. Both sexes have a brown hindwing  with the female having additional narrow white streaks arranged as per the Ideopsis species.  Underneath, the wings are brown with white spots/streaks arranged similarly to those on the upperside though with variation in size of the spots/streaks.

A  female Striped Blue Crow feeding on  Syzygium flowers in an open-wing posture.

A male Striped Blue Crow visiting Syzygium flowers.

Another male Striped Blue Crow on a leaf perch.

Field Observations of Butterfly Behaviour:  
The sexually dimorphic Striped Blue Crow is the most common Crow species in Singapore. Though not abundant, the adults have been observed in many locations, including the nature reserves, mangrove habitats,  wastelands and even in urban parks and gardens. The adults are attracted to flowers, and are easiest to approach for photo-taking when they are occupied during their flower visits.  

Early Stages:
The Striped Blue Crow is polyphagous and has many larval host plants in the Moraceae, Apocynaceae and Asclepiadaceae families.  The fact that it can utilize some many hosts which grow in multiple types of habitats account for its wide distribution  and the common status in Singapore. The caterpillars of Striped Blue Crow feed on leaves and young shoots of the host plants, typically with the early instars focusing on  young tender leaves and  later instars moving on to the more mature leaves. The caterpillar has the habit of first cutting the mid-rid or the petiole of a leaf  before eating the leaf lamina beyond the severed point. A web of silk threads helps to secure the severed or nearly severed part.

Local host plant: Ficus microcarpa.

Local host plant: Gymnanthera oblonga.

A mother Striped Blue Crow laying egg on the underside of a young leaf of F. microcarpa.

The eggs of the Striped Blue Crow are laid singly on the underside of a leaf (typically young leaf) of the host plant. The creamy yellow eggs are tall (about 1.8-1.9mm in height) and somewhat cylindrical (diameter: 1.2mm) with a rounded top. The egg surface is ribbed.

Two views of an egg of the Striped Blue Crow.

Two views of a mature egg of the Striped Blue 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 3.2mm. The newly hatched has a pale yellowish  body and black legs. The large head capsule is black in color. A pair of very short and inconspicuous protuberances can be found on the dorsum of each of the following four segments: 2nd and 3rd thoracic segments, the 2nd and 8th abdominal segments.

Two views of a newly hatched caterpillar, length: 3.2mm.

Once the newly hatched moves on to feed on the leaf lamina, its body starts to take on a green undertone. The newly hatched has this interesting  habit of marking out a  portion of the leaf with  a series of small spots before eating away the marked out portion. In the final half day of the 1st instar, the body takes on yellowish brown transverse stripes on all segments. This instar lasts for 2-2.5 days with the  the body length doubled up to 7 mm.

Two views of a 1st instar caterpillar,  length: 5mm

Two views of a 1st instar caterpillar, late in this stage, length: 6.9mm.

The body of the 2nd instar caterpillar has a yellow ground color. There are dark brown  transverse rings interspersed with whitish stripes on each of the body segments except for the very 1st segment. The most obvious change is the lengthening of the 8 tiny protuberances seen in the 1st instar to short processes, each of which is almost entirely dark brown to black. There are two small black spots on the dorsum of the prothorax, and one large black patch (anal plate) on the posterior end of the body. This instar lasts only 1.5 days with the body length reaching 12mm before the moult to the 3rd instar.

Two views of a 2nd instar caterpillar, early in this stage, length: 7.5mm

Two views of a 2nd instar caterpillar, length: 9mm

The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar with the only obvious change being the proportionally longer processes. Less obvious is the lengthening of a whitish transverse stripe on each segment to below the sub-spiracular area.  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 16-18mm.

Top: Late L2 prior to the moult. Bottom: newly moulted 3rd instar caterpillar, length: 11.5mm.

Two views of a 3rd instar caterpillar, length: 13.5mm.

Compared to the 3rd instar, the 4th instar caterpillar has proportionally longer processes.  On the body segments, the transverse white stripes are now prominent with one stripe being broader on the dorsum of each abdominal segment. The lower end of a white transverse stripe on each of the first seven abdominal segment is  constricted to form a white triangular patch.  The black head capsule features two frontal, and oblique  white stripes and  an outer peripheral white ring. This instar lasts 1.5 to 2 days with the body length reaching about 24-28mm.

Top: Late L3 prior to the moult. Bottom: newly moulted 4th instar caterpillar, length: 17mm.

Two views of a 4th instar caterpillar, length: 28mm.

The 5th instar caterpillar again has proportionately longer processes. An obvious change is in  the basal third or quarter of each process being coloured carmine in place of dark brown/black. Another change is in the head capsule where the frontal and peripheral white stripes are now much broader and joined.The white and dark-colored transverse stripes dominate the body surface so much that the yellow coloration is only confined to the prothorax, small lateral patches and the posterior segment.

Two views of a 5th instar caterpillar, length: 34mm.

The Striped Blue Crow caterpillar, unlike the Blue Spotted Crow (E. midamus singapura) and the King Crow (E. phaenareta castelnaui), does not have an adenosma (or prostenal gland, located just ahead of the 1st pair of thoracic legs). When the caterpillar was  intentionally agitated, no eversion of any structure can be seen (at the expected location) in multiple observations. The caterpillar merely adopted a head-tugged defensive stance in such occasions.

A 5th instar caterpillar found in the nature reserve on Ficus lamponga, adopting a defensive stance.

In some specimens, the colour change to carmine in the basal part of the processes  also extend to the dark brown transverse stripes on the body segments and even to the head capsule. In another colour variant, the usual bright yellow coloration on body markings is replaced by  a pale shade of  yellow.

Two views of a 5th instar caterpillar with more extensive carmine coloration length: 29mm.

Two views of a 5th instar caterpillar, late in this instar,  length: 43mm.

Two views of a 5th instar caterpillar, with more extensive carmine and paler yellow coloration, late in this instar,length: 46mm.

The 5th instar lasts for 3.5-4 days, and the body length reaches up to 51-53mm. On the last day, the caterpillar ceases feeding, and its body becomes shortened and decolorised to a shade of pale beige 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.

A pre-pupatory larva of the Striped Blue Crow.

Pupation takes place 0.5 days after the caterpillar assumes the hanging posture. The pupa  suspends itself from the silk pad with no supporting silk girdle. Initially, the pupa is in a light shade of yellowish brown, but the surface gradually takes on a silvery metalic glitter about a day later. The pupa is rather rotund, and has a few tiny black spots  on the dorsum. Length of pupae: 19-21mm.

Three views of a fresh pupa of the Striped Blue Crow, several hours after pupation.

Three views of a shining pupa of the Striped Blue Crow, one day  after pupation.

Three views of a mature pupa of the Striped Blue Crow, night before eclosion.

After about 6-7 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 male Striped Blue Crow drying its wings on its pupal case.

A newly eclosed female Striped Blue Crow drying its wings on 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.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006
• A Field Guide to the Butterflies of Singapore, Khew S K, Ink on Paper Comm. Pte. Ltd, 2010.

Text by Horace Tan, Photos by Benedict Tay, Federick Ho,  Sunny Chir, Khew SK  and Horace Tan