Friday, June 5, 2015

Butterfly of the Month - June 2015

Butterfly of the Month - June 2015
The Dark Posy (Drupadia theda thesmia)


A female Dark Posy perching on a leaf

The month of June 2015 is an exciting month for Singapore nature, with two big events showcasing our local biodiversity happening during this school holiday month. In the coming weekend (13-14 Jun), NParks will be organising "Ubin Day" (should rightfully be called Ubin Weekend this year) with a bunch of very energetic and enthusiastic volunteers and nature groups.




Then at the end of June, we will have the fourth instalment of the Festival of Biodiversity at VivoCity Mall on the 27-28 June. ButterflyCircle will have a booth at the FOB2015 to feature our members' work as well as bringing some new attractions this time! The Festival of Biodiversity is also organised by NParks, and this festival to showcase Singapore's awesome biodiversity first started in 2012 at the Singapore Botanic Gardens. Do look out for our ButterflyCircle booth at the end of this month at FOB2015!





Last week, I had the opportunity of spending a whole week back in my hometown of Penang in Malaysia. My company had our Board meeting there. We also brought our Directors to visit some of our projects that are underway and to meet with our Malaysian clients. We also took the chance to visit some local historical sites to understand more about Penang.



A quick visit to the Kek Lok Si Temple complex brought back many fond childhood memories and despite many spanking new facilities and temples, I still had a preference for the old "yellow pagoda" which I climbed many times in my childhood and teenage years. This time around I approached the temple with a bit of trepidation because I wasn't sure if I was fit enough to make it to the top, having last climbed the pagoda about 25 years ago!



Fortunately, I still made it! The view at the top was no less exhilarating, although it was no longer the tallest structure around, like in the old days. As a young boy, I was told that there were 1,000 Buddha tiles adorning the walls of each storey of the pagoda - changing from bronze to gold as one climbs higher up. And then there was this old wives' tale that once you pass the threshold of the entrance of the pagoda, you must climb all the way up to the highest level for good luck!



Over in East Malaysia, the wrath of Mother Nature was felt again, this time when a 6.0 MMS magnitude earthquake struck near Mount Kinabalu in Sabah. Although not a major earthquake, magnitude-wise, as compared to the one that struck Nepal, it coincided with the school holidays and several school groups were making the climb up to the peak at that time. It was heart-breaking to learn that a Sabahan guide and a 12-year old Singaporean school girl lost their lives in the quake.



At the time of writing, 8 pupils and 2 teachers are still unaccounted for. It must be a traumatic time for the parents and loved ones of these students and teachers, and we can only pray that they are safe somewhere up on Mount Kinabalu.  But it is sad to read on social media how clueless commenters have started to blame the authorities, Ministries, schools and everyone else under the sun.  


A male Dark Posy resting in the shade.  Note its shorter sword-like tails

Coming back to our Butterfly of the Month for June 2015, we feature a small but attractive 'hairstreak' butterfly, the Dark Posy (Drupadia theda thesmia). This species is considered moderately rare in Singapore, and usually found in the forested nature reserves. Occasionally, several individuals may be seen together, frolicking at tree-top level in the late hours of the afternoon, basking on the tops of leaves when the sun shines through the forest canopy.


A male Dark Posy sunbathes showing its purple-blue upperside

The male is dark purple above with an orange discal patch on the forewing. This form, f-minara is the typical male form found in Singapore. Like its close cousin, the Common Posy (Drupadia ravindra moorei), it can sometimes be seen opening its wings to sunbathe in the late afternoon hours on a hot sunny day.


A female Dark Posy sunbathes showing its upperside

The female is brown with a bluish grey tornal patch on the hindwing which has a few black submarginal spots. The forewing post-discal area usually feature a small orange patch that can sometimes be obsolete in some individuals. Females of the Dark Posy also have slightly longer tails compared to the males.


Visual ID key to distinguish between the Common Posy (left) and the Dark Posy (right)

On the underside, the forewing is a deep orange, marked with darker transverse stripes, whilst the hindwing is white with black spots and lines. This species can be separated from the similar-looking Common Posy in that the space between the two black stripes forming the cell-end bar on the hindwing beneath is white, and not solid black as in the Common Posy.



Males are more skittish and are active in the afternoons on hot sunny days. They tend to select a few favoured perches and then flit from perch to perch where they sometimes open their wings to sunbathe. Female Dark Posies prefer to feed on the sweet sap from the young shoots of plants, and indeed, they have often been encountered doing so, in the forested areas.




The life history of the Dark Posy has been succesfully recorded on the forest creeper, Combretum sundaicum, a host plant that it shares with several other butterfly species in Singapore. You may refer to the detailed life history of the Dark Posy here.


Text by Khew SK : Photos by Sunny Chir, Khew SK, Koh CH, Loke PF, Nona Ooi and Horace Tan

Saturday, May 30, 2015

Life History of the Philippine Swift

Life History of the Philippine Swift (Caltoris philippina )


Butterfly Biodata:
Genus: Caltoris Swinhoe, 1893
Species: philippina Herrich-Schäffer, 1869
Sub-species: philippina Herrich-Schäffer, 1869
Wingspan of Adult Butterfly: 30-34mm
Caterpillar Local Host Plants: Bambusa_heterostachya (Poaceae; common name: Malay Dwarf Bamboo), Bambusa vulgaris (Poaceae, common names: Common bamboo, Buloh Minyak, Buloh Kuning).




Physical Description of Adult Butterfly:
The forewing is distinctly excavate at vein 2. On the upperside, the wings are dark brown. The forewing does not have any cell spots, but  there are  hyaline spots in spaces 2,3 and 4, subapical spots in spaces 6 and 7.  In addition,  the male has a pale yellow spot in the lower half of space 1b of the forewing. On the underside, the wings are unicolourous with a strong greenish tinge.

A male Philippine Swift with partially opened wings, showing the lack of forewing cell spots.

A male  Philippine Swift with partially opened wings, showing the arrangement of spots on the forewing upperside.

Field Observations of Butterfly Behaviour:
The Philippine Swift is rare in Singapore. Sightings typically took place in nature reserves or wastelands where clumps of bamboo are growing in the vicinity. The adults are usually seen perching on a leaf in a shady environment. At times, they have been observed to puddle on bird droppings.  





Early Stages:
The Philippine Swift has been bred on two bamboo spp., namely, Bambusa_heterostachya and Bambusa vulgaris. The caterpillars feed on leaves of these bamboo spp. and live in leaf shelters formed from cutting/folding leaf fragments.

Local host plant #1: Bambusa_heterostachya.

Local host plant #2: Bambusa vulgaris.

The eggs are laid singly on the upperside of a leaf of the host plant. Each hemi-spherical egg is whitish with a small reddish/orangy patch at the top where the micropyle  is situated. A number of very fine and obscure  striations running longitudinally from the micropyle to the base. The basal diameter is about 1.1mm.

Two views of an egg of the Philippine Swift.

It takes about 4.5-5 days for the egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 2.9mm. Its golden yellowish  body is cylindrical in shape and has a tuff of few moderately long setae at the posterior end. The head capsule is black. A black collar mark can be found the dorsum of the prothorax. The newly hatched nibbles away most of the egg shell remnant before proceeding to construct its first leaf shelter.

A newly hatched caterpillar eating its egg shell.

A newly hatched caterpillar in its very first leaf shelter. Further "stitching" work by the caterpillar will bring the two opposite edges together.

The body turns yellowish green after the caterpillar has a few sessions of the leaf diet. By the time the caterpillar lies dormant for its moult to the 2nd instar, its length has reached 5-5.5mm. The 1st instar takes a total of 3-3.5 days to complete.

Two views of a 1st instar caterpillar, length:4.5mm.

Two views of a 1st instar caterpillar, dormant prior to its moult, length:4.9mm.

The 2nd instar caterpillar has a yellowish green body, and the head capsule is still black. The black collar mark on the prothorax has faded to just to hint of its presence. This instar lasts about 3-4 days with the body length reaching about 8.5-9.5mm.

Two views of a 2nd instar caterpillar, early in this stage, length: 5mm.

Two views of a 2nd instar caterpillar, length: 6.5mm.

The 3nd instar caterpillar still has a black head capsule but its body is now whitish with a slight hint of yellowish green. There is no longer any trace of the black collar mark on the prothorax. This instar lasts a total of 3-4 days with the body length reaching about 14-15mm.

Two views of a 3rd instar caterpillar, early in this stage, length: 8mm.

Two views of a 3rd instar caterpillar, length: 11.5mm.

The 4th instar caterpillar resembles the 3rd instar caterpillar closely. In some specimens, the head capsule is no longer entirely black as pale brownish lateral patches can be observed. This penultimate instar lasts 4-5 days with the body length reaching up to 20-21mm.

Two views of a 4th instar caterpillar, early in this stage, length: 14mm.

Two views of a 4th instar caterpillar, length: 20mm.

As in the 4th instar, the 5th instar caterpillar has a whitish body with a yellowish green undertone. In a prominent change, its head capsule is now pale biege brown in ground colour but dark reddish brown along the periphery and various sulci (groove/furrow). Two reddish brown stripes rise from the adfrontal area, giving the appearance of a chinese character . The anal plate is unmarked as in the all previous instars. This final instar takes about 8-10 days to complete with the body length reaching 30-35mm.

Two views of a newly moulted 5th instar caterpillar, length: 20mm.

Two views of a 5th instar caterpillar, length: 30.5mm.

Two views of another 5th instar caterpillar, length: 32mm.

Towards the end of 5th instar, the body of the caterpillar shortens in length and body colour assumes a uniform shade of pale lime green. It seeks out the underside of a leaf blade and forms a shallow but half-open shelter with silk threads at both ends. The body excretes a moderate amount of white waxy material at this stage. Within the shelter, a silk girdle and a silk pad are then spun. Once the caterpillar attaches its claspers to the silk pad, it enters the dormant prepupatory phase which lasts about one day.

Two views of a dormant pre-pupa of the Philippine Swift.

The pupa secures itself with the silk girdle and with its cremaster attached to the silk pad. It has a short thorax, a rather long abdomen, a short and pointed rostrum. The marking-free body is lime green in the thorax and wing pads but more yellowish green in the abdomen. Length of pupae: 25-30mm.

Two views of a pupa of a male Philippine Swift, length: 25mm.

After 7-8 days, the pupa becomes mostly black in the thorax and wing pads as the development within comes to an end. The next day, the adult Philippine Swift emerges from the pupa.

A mature pupa of the Philippine Swift.

A newly eclosed Philippine Swift, resting on its pupation shelter.

References:
  • [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society, 1992.
  • Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012.
  • A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2010.
Text by Horace Tan, Photos by Lemon Tea, Tan Ben Jin, Chng CK, Sunny Chir and Horace Tan

Saturday, May 23, 2015

Butterfly of the Month - May 2015

Butterfly of the Month - May 2015
The Spotted Black Crow (Euploea crameri bremeri)


The Spotted Black Crow feeding on the flower of the Sea Ox Eye (Melanthera biflora) a "weed" that is found in abundance in back mangrove areas

The month of May saw the weather changing from hot and dry to several days of torrential rain and gloomy weather. The earlier forecast of a dry spell by the National Environment Agency's Meteorological Service was quickly amended to warnings of intermittent thunderstorms and hot humid weather again.




The expected 'butterfly season' this year did not materialise. ButterflyCircle members who were out in the field all reported a rather consistent observation - that there were fewer butterflies at this time of the year compared to previous years. Did any weather phenomenon alter the butterfly activity? Or is this an exceptional year where there is distinctly a lower butterfly count than before? Whether this will continue in the coming years, we will have to continue to observe.




Globally, the wrath of Mother Nature was felt in Nepal, with a major earthquake striking towards the end of April, and another aftershock that occurred on 12 May. Considering the enormity of the earthquake, registering 7.8 on the Moment Magnitude Scale, casualty was around 8,000 fatalities and over 19,000 injured and even more made homeless.



If such an earthquake were to strike a more densely populated city, the casualty rate would have been unimaginable. Still, a life lost is a life lost. And the unfortunate citizens of Nepal who made it through the aftermath of the disaster need a lot of help in picking their lives up. My company organised an in-house donation drive, and managed to raise over S$8,000 for the victims of the quake. A lot more needs to be done, and different groups are organising themselves to give whatever assistance they can - in cash, in kind and other forms of aid.




One of the favourite nectaring source of the Spotted Black Crow is the StringBush (Cordia cylindristachya)

Over in Singapore, the SG50 (celebration of Singapore's 50th anniversary) events continue in various shapes and sizes. Preparation for the 28th South East Asian (SEA) games in Singapore is well under way. The games will commence on 5 Jun till 16 Jun. It has been 22 years since the games were held in Singapore - the last time being in 1993. With Singapore's new Sports Hub and updated facilities since then, the games venues are expected to be more sophisticated.


A Spotted Black Crow feeds on the flower of Bidens pilosa

This month, we feature one of the many "Crow" butterflies of Singapore, the Spotted Black Crow (Euploea crameri bremeri). The Crows from the genus Euploea feature medium-sized butterflies with predominantly dark coloured (navy blue or black) wings. The characteristic black or blue butterflies with prominent white spots and streaks, resembling their avian namesake Crows, probably gave rise to their collective name for this group of butterflies.


A Spotted Black Crow feeding at the flowers of Syzygium zeylanicum

The Spotted Black Crow is moderately rare in Singapore, and often observed singly where it occurs. The adult butterfly has an average wingspan of 70-90mm. It is usually found in forested areas, and particularly near mangrove and coastal areas like Pasir Ris Park, Pulau Ubin and Sg Buloh Wetland Reserve.



Visual ID key to distinguish between the Spotted Black Crow (left) and the Blue Spotted Crow (right)

The Spotted Black Crow's wings are predominantly black on the upperside and underside, except for the series of white marginal and submarginal spots on both the fore and hindwings. There are five apical spots on the forewing, two large and three small elliptical spots. The smallest spot on the forewing is one of the distinguishing features that separate this species from the closely-related Blue Spotted Crow (Euploea midamus singapura).



Unlike some of the other species in the genus, the male Spotted Black Crow does not have a brand on the forewing. The number of white spots on the hindwing and marginal area can be variable, and some individuals can have either missing spots, or larger than usual spots on the hindwings. Females are paler than the males.



Examples of the Spotted Black Crow pudding on damp concrete structure and on a damp sandbank

The butterfly flies and glides unhurriedly whilst looking for flowers to feed on. However, it is very alert and when photographing this species, a slight movement would make the butterfly take off quickly. Occasionally, males can be observed puddling at damp sandbanks and concrete structures in the nature reserves.



When alarmed the male Spotted Black Crow extrudes a pair of yellow hair pencils from its abdomen. These hair pencils are pheromone-signalling structures often present in male Danainae butterflies. Males Danainaes use hair-pencils in courtship behaviours with females. The pheromones excreted by the hair-pencils serve as both aphrodisiacs and tranquilizers to females as well as repellents to conspecific males



The full life history of the Spotted Black Crow has been successfully recorded on this blog, and can be found here. The local caterpillar host plants in Singapore are Gymnanthera oblonga (Apocynaceae, common name: Sea Rubber Vine), Parsonsia helicandra (Apocynaceae). Both plants are lactiferous and are often found in the vicinity of mangrove areas.



The typical colour and spots of the Crows are believed to be aposematic colouration that signal to would-be predators (especially birds) that the butterflies are distasteful and should be avoided.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Jerome Chua, Federick Ho, Khew SK, Loke PF, Horace Tan and Jonathan Soong