Butterfly of the Month - March 2010

Butterfly of the Month - March 2010
Pale Grass Blue (Zizeeria maha serica)

This month, as signs of spring begin to emerge in the northern hemisphere after a somewhat harsh winter in many temperate countries, Singapore faced what was one of the driest months in 140 years! The National Environment Agency (NEA) in Singapore reported that February 2010 saw only 6.3mm of rain. February, traditionally one of the driest months in a typical year, was made worse by the El Nino effect, and the hot dry weather is expected to last until May.

Our butterflies though seemed to be still quite happily fluttering around, with more discoveries and new observations being recorded by members of ButterflyCircle. Whilst the news of these interesting observations will be recorded in due course on this Blog, we feature a relatively common and small Lycaenid for the month of March 2010 - The Pale Grass Blue (Zizeeria maha serica).

The Pale Grass Blue is one of our "foreign talents" that arrived in Singapore some time before 2001, and have remained ever since. A species that was not on the records and checklists of the early authors, the Pale Grass Blue was first discovered by ButterflyCircle member Steven Neo, and his son Abiel Neo back in October 2001. Steven tells me that whilst photographing butterflies at a hedge near his home one day, and after developing the film (yes, in those days, digital cameras were non-existent or exorbitantly out of reach of the masses), he got a shot of a rather strange Lycaenid that did not match the species in reference books for Malaysia/Singapore butterflies.

It remained an unidentified species until in Nov 2002 when I communicated with Col John N Eliot, the butterfly guru who was responsible for the 4th Edition of the Butterflies of the Malay Peninsula by Corbet & Pendlebury. Col Eliot confirmed that the photos of the specimens that I sent to him were indeed Zizeeria maha serica of which the type specimen originated from Hong Kong.

He opined that the little butterfly probably arrived in Singapore, aided inadvertently by human agency, as a butterfly with a wingspan of no more than 15mm was unlikely to have flown here on its own steam. Col Eliot wrote an aerogramme to me on 12 Nov 2002, and another one on 9 March 2003, discussing the discovery of Zizeeria maha serica and other news about Singapore's butterflies. Those aerogrammes are safely preserved in my archives today, and our discussion about this rather diminutive and 'insignificant' butterfly must have been one of the last few that Col Eliot wrote about.

Sadly, just about a month after he wrote to me on 9 March 2003, Col Eliot passed away on 11 Apr 2003, being well over 90 years of age then. The world of Asian Lepidoptera lost one of its foremost and most accomplished expert who had contributed immeasurably to the knowledge of butterflies in the region.

We now come back to the little butterfly, the subject of our discussion, Zizeeria maha serica or what we prefer to refer to as the Pale Grass Blue. The male of the species is light purplish blue above, with dark bluish black borders on the forewings and costal margin of the hindwings. The submarginal spots on the hindwings above separate it from the two similar looking species in Singapore - Lesser Grass Blue (Zizina otis lampa) and Pygmy Grass Blue (Zizula hylax pygmaea).

The female is predominantly dark greyish blue above. On the underside there is a series of dark spots on the forewings and hindwings. The more prominent submarginal spots and markings on both the fore and hindwings set it apart from the other two lookalike species.

The Pale Grass Blue can be found mainly in urban parks and gardens, where its preferred caterpillar host plant, Oxalis corniculata (Oxalidaceae) or the Yellow Sorrell is found. It has a rather restless erratic flight but a relatively weak flyer. It flies low and close to grassy turfs and stops to feed on wild flowers. Occasionally, individuals are observed resting in the shade with their wings folded upright.

So goes the story of one of our first discoveries of a new taxon to the Singapore butterfly fauna, and with special thanks to Steven Neo, a long time friend and a veteran butterfly enthusiast in Singapore (who is also the author of the only dedicated book on butterflies of Singapore - the Science Centre series - A Guide to the Common Butterflies of Singapore)

Text by Khew SK : Photos by Sunny Chir, Federick Ho, Khew SK & Horace Tan

References :

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition 1992, Malayan Nature Society
• The Malayan Nature Journal, Vol 59, Part 1, Oct 2006, Malaysian Nature Society

Life History of the Large Dart

Life History of the Large Dart (Potanthus serina)



Butterfly Biodata:
Genus: Potanthus Scudder, 1872
Species: serina Plötz, 1883
Wingspan of Adult Butterfly: 32mm
Caterpillar Host Plants: Flagellaria indica (Flagellariaceae)

Physical Description of Adult Butterfly:

The Large Dart is the largest of all Potanthus species, approaching the size of a Telicota species. Above, markings are orange-yellow, with the spot in space 6 on the hindwing very small or absent, and the three apical spots are separate from the spots in spaces 4 and 5. Underneath, the markings carry an orange tinge, and the spot in space 5 on the forewing is not completely detached from that in space 6.

A female Large Dart.


A male Large Dart.

Field Observations of Butterfly Behaviour:

This species is only recently re-discovered and added to the Singapore checklist. Adult sightings have so far been made in multiple habitats such as wastelands, nature reserves and mangrove areas, where the host plant can be found growing. During these sightings, adults have been observed to carry out activities such as visiting flowers, sunbathing and puddling.

Early Stages:

Host plant: Flagellaria indica. Note the coiled leaf tips and white flowers.

The host plant, Flagellaria indica, is a climber with strong but slender stems. The leaves are linear-oblong and 8-25cm long. Usually, the leaf tip ends in a coiled tendril. Flowers are white and occur in a branched terminal panicle. This plant is common in open thickets near the sea and in the local nature reserves. The caterpillars of the Large Dart feed on leaves of this plant, and live in shelters made by joining edges of a leaf together with silk threads.

Leaf shelter construction by caterpillars of the Large Dart (3rd and 5th instar).

The eggs are laid singly on the leaf, either on the basal part or on the coiled tendril. Each hemispherical egg is creamy white with a slight yellow tinge. The micropylar sits atop. The surface is covered with many tiny pits, almost indiscernible to the naked eyes. The base diameter is about 1mm.


An egg of the Large Dart laid on the coiled leaf tip.


Two views of a "fresh" egg of the Large Dart.


Two views of a developing egg. The red markings appear on day 2.


Developing eggs. Left: showing a vague outline of the developing caterpillar.
Right: fully developed and nibbling away egg shell prior to emergence.

It takes 4-5 days for the egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 2.8mm. Its has a cylindrical body shape, rather short dorso-lateral and sub-spiracular setae and a tuff of long setae on the posterior end. The head capsule is black and there is a black "colar" on the prothorax.

Newly hatched 1st instar caterpillar, length: 2.9mm

The body is initially goldenrod in colour but changes to yellowish green after a few feeding sessions on the leaf. The newly hatched constructs its leaf shelter as one of its first tasks after the hatching. Between feedings, the caterpillar retreats to its shelter for rest and safety. By the time the caterpillar lies dormant in its shelter for the moult to the 2nd instar, its length has reached 6mm. The 1st instar takes about 2.5 days to complete.

1st instar caterpillar, late in this stage, length: 5.5mm.

The 2nd instar caterpillar is yellowish green in color and the short dorso-lateral and lateral setae are now absent. The anal plate still carries a few setae but these are not as long and prominent as in the 1st instar. The head is black in color and the black colar on the prothorax is retained. This instar lasts about 3 days with the body length reaching about 9.5-10mm.

2nd instar caterpillar. Lengths: 7mm (top); 9.5mm (bottom).

The 3nd instar caterpillar resembles the 2nd instar caterpillar closely in markings and coloration, with the exception that the head capsule now has elongated whitish patches running down each side of the "face". This instar lasts about 3 days with the body length reaching about 17mm.

3rd instar caterpillar, female, early in this stage. Length: 9mm.


3nd instar caterpillar, male, early in this stage. Length: 9mm.

The 4th instar caterpillar also resembles the 3rd instar caterpillar with the only visible change being the two lateral white stripes on the head capsule are now broader and more dominant. In addition, thin white outlines, in the shape of an inverted "Y", also appear within the central black marking. This instar lasts 2.5-3 days with the body length reaching up to about 22mm.

4th instar caterpillar. Lengths: 13.5mm (top); 16mm (bottom).

The 5th (and final) instar caterpillar has no visible change in markings or coloration from the 4th instar. This instar takes about 5 days to complete with the body length reaching about 35mm.

5th instar caterpillar. Lengths: 24mm (top); 32mm (bottom).

Towards the end of the 5th instar, the the body of the caterpillar shortens and its coloration changes to a translucent pale green. Soon it becomes dormant in its leaf shelter and enters the prepupatory phase which lasts for one day During this time period the body color of the pre-pupa changes to yellow, and a fair amount of silk threads and white waxy substance are deposited within the tight confine of the leaf shelter.

Two views of a pre-pupa of the Large Dart.

Pupation takes place within the tight leaf shelter. The pupa does not secure itself with any cremastral attachment nor any silk girdle. It is mainly yellow brown and has a rather long abdomen and a thorax. Length of pupae: 20-22mm.


Three views of a pupa of the Large Dart, length: 21mm

After 8 days, the pupa becomes mostly dark brown with yellow markings apparent in the wing pads. Eclosion takes place the next day.


Three views of a mature pupa of the Large Dart, shortly before the eclosion event.


A newly eclosed Large Dart.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

Text and Photos by Horace Tan

Two Skips and a Growl

Two Skips and a Growl
Updating the Singapore Butterfly Checklist to 294

The addition of these three species - two Hesperiidae and one Danainae to the Singapore Butterfly Checklist has been long overdue. The Checklist, which now stands at 294, dates back to the early 90's when Steven Neo first started his surveys with the National Parks Board. Having taking over the baton from the late 90's I have kept intact, all the species that Steven had earlier recorded - some of which have not been seen since the early 90's.

The addition of the two Skippers and a Tiger doesn't bring the checklist to a close. In fact, as ButterflyCircle has more and more 'eyes and ears' on the ground, it is likely that there will be more discoveries and re-discoveries in the coming years, particularly in the Lycaenidae and Hesperiidae families where there are numerous lookalike species.

The limitation of field observations and photographs taken of either the upper or underside of a lookalike species cannot be understated. Up to a certain extent, field identifications are possible, but where close scrutiny of both the uppersides and undersides and also males and females of a species to confirm the species' identification with a higher level of confidence, the collection of voucher specimens become necessary. Without the requisite collecting permits from the authorities, the addition of species that are hitherto not recorded would be impossible.

The family Hesperiidae comprises rather unattractive and moth-like species and often under-researched as far as butterflies are concerned. This may be why the majority of new species discovered fall into this family - both locally and also globally.

The Large Dart (Potanthus serina)

The first re-discovery is from the genus Potanthus. Comprising a genus that features a total of 13 species in the Malaysian butterfly fauna, of which 5 species have been recorded in the past, we have only documented the Lesser Dart (Potanthus omaha omaha) as the only extant species in Singapore.

We now record the existance of the Large Dart (Potanthus serina) with a high level of confidence, having bred the entire life history of this species, as well as scrutinised several specimens - both males and females from various locations. The early stages will be featured in an upcoming article in this blog.

The Large Dart was named Potanthus hetaerus serina in early references but recently updated to its current name of Potanthus serina. It is the largest of the species in the genus, attaining a wingspan of up to 32mm. A characteristic feature of this species is that the three subapical spots are separate from the spots in spaces 4 and 5, and are not completely dislocated at vein 6 where the spots in spaces 5 and 6 overlap and not completely detached . The veins are dark dusted on the upperside of the hindwings. On the hindwing beneath, the ochreous scaling is orange-tinged.

The species frequents grassy areas and has been found in the nature reserves as well as in mangrove areas. Like most of its other close relatives in the genus, it is a rapid flyer. It is often observed in shaded areas in the afternoons, with its wings folded upright. In the early morning hours, one can observe it displaying the usual skipper pose, with the forewings held at an angle whilst the hindwings are opened flat.

The Common Palm Dart (Telicota colon stinga)

The record of this species, one of three in this genus. Records of this genus show that there are six species in the Malaysian and Singapore region, of which three have been recorded. With the confirmation of this species, all three are now extant in Singapore.

The presence of this species has been overlooked all this time, primarily due to field observations of the lookalikes of the genus Telicota. The other two species, T. augias and T. besta bina have been recorded earlier with voucher specimens. This latest re-discovery would not have been possible without breeding the early stages as well as dissection of the genitalia of a bred male specimen by ButterflyCircle member Chan Soon Chye. Having the benefit of comparing the details of the genitalia with the reference diagrams in the Butterflies of Singapore by Corbet & Pendlebury, and the descriptions of the species, the Common Palm Dart is now re-instated to the Singapore Checklist.

The Common Palm Dart is a relataively large skipper, attaining a wingspan of up to 36mm. The yellow colour of the post-discal band on the forewing is continued along the veins towards the termen. The bluish-grey stigma on the forewing in the male is more conspicuous that in the other species.

It is another rapid flyer and males are often seen 'dogfighting' in the early hours of the morning, and then resting on leaves and grass blades in the usual Skipper pose.

Yellow Glassy Tiger (Parantica aspasia aspasia)

Sightings of this Danainae have been recorded in the past, but it was uncertain as to whether the individuals sighted were actually imported products of human agency or free-ranging immigrants straying into Singapore during the NE monsoon season when the north-easterly winds tended to bring species from the southern part of the Malay Peninsula into Singapore.

Another recent sighting of a female at Hort Park, feeding on the flowers of the Indian Heliotrope (Heliotropium indicum) prompted us to record this species as a re-discovery. Though documented in the early authors' checklists, this species appears to be more of a seasonal migrant rather than an extant species in Singapore. It is still a mystery why this species no longer appears with regularity in Singapore, like its common cousins, the Dark Glassy Tiger (Parantica agleoides agleoides) and the Blue Glassy Tiger (Ideopsis vulgaris macrina).

A female Yellow Glassy Tiger shot recently at the Hort Park

Perhaps the species' preferred host plant is no longer available? Or the habitats are unconducive for its permanent re-establishment in the Singapore environment? As it is a rather common species in the Malaysian forests, further research may help us reach a conclusion as to why this species is not able to stay on permanently. This is one of the species that could be the subject of a re-introduction programme together with NParks after the host plants are cultivated at strategic habitats around the island. The Life History of the Yellow Glassy Tiger, recorded by ButterflyCircle member LC Goh in Kuala Lumpur can be found here.

With these three additions, the Singapore Butterfly Checklist now stands at 294 species. The checklist is by no means complete, as new additions are to be expected as more and new information is available on our butterfly species. There have been many 'extinctions' but also many new discoveries of species that were not on the early authors' original checklists.

As we move into a new decade in 2010 and also celebrate the International Year of Biodiversity, let us look forward to more additions to the Singapore butterfly fauna and work to conserve the species that have already made Singapore home.

Text by Khew SK ; Photos by Khew SK, Bobby Mun, Horace Tan, Anthony Wong & Mark Wong

References :

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition 1992, Malayan Nature Society.
• Butterflies of West Malaysia and Singapore, W. A. Fleming, 2nd Edition 1983, Longman Press
• The Malayan Nature Journal, Vol 59, Part 1, Oct 2006, Malaysian Nature Society

Tigers and the Belimbing

Tigers and the Belimbing
Sg Buloh Wetland Reserve on a hot sunny Tuesday

It was a hot and windy day, and the searing heat seemed to chase even the most robust of butterflies into hiding. However, at a remote corner of the wetland reserve, was a clump of trees that provided much-needed sustenance to more than a dozen Blue and Dark Glassy Tigers.

The typical long bi-pinnate leaf arrangement of the Belimbing tree

The trees were flowering from the trunks, as is the normal case for this species of Camias (Averrhoa bilimbi) or the Belimbing as the locals call it. The Belimbing fruit is well-known for its sour and adicic taste. The species is a close relative of the Starfruit (Averrhoa carambola) another well loved fruit in South East Asia.

The attractive flowers of the Belimbing

The tree is native to Malaysia and Indonesia. The Belimbing is well known for its green 'papaya-shaped' fruits that grow to about 10cm long. Most of the time, the Belimbing is dropped into dishes that call for a tangy or sour taste, such as sambals, pickles and chutnies, and is a regular addition to Peranakan cuisine and many local Malaysian dishes. The juice of the fruit has many medicinal uses as well.

The fruits of the Belimbing hang straight off the branches and trunk of the tree

The Belimbing trees at SBWR have always been at this location, but this is probably the first time that I've encountered them flowering and fruiting in profusion. Lucky for the butterflies too, as the Blue and Dark Glassy Tigers seemed to be in season this period, and I stopped counting them during the walk after reaching a total of 30.

The red-purple flowers of the Belimbing are pretty and attractive in their own right. Unlike their sour fruits, I'm quite sure the nectar is sweet, as the butterflies were scrambling over each other, going for the fresher flowers on the tree.

Besides the dominance of the Glassy Tigers, other species that were also spotted around the tree that also stopped for a taste of the nectar were the Common Grass Yellow, a King Crow and an unidentified Arhopala which scooted off quickly as I approached it.

A Common Grass Yellow and Dark Glassy Tiger joining in the nectar feast at the Belimbing tree

The structure of the flower is such that the stamens and pistil extend outwards and I observed that as the butterflies' proboscis reached deep into the flower for nectar, the body and legs of the butterflies were doing their work in pollinating the flower.

Pollinating the flower whilst feeding on nectar

From the photography viewpoint, shooting the rather drab-coloured 'tigers' complemented with the strongly coloured flowers of the Belimbing added a nicer dimension to the otherwise boring butterfly in terms of colour balance and composition.

Text and Photos by Khew SK

Further Reading :

• Camias (Belimbing) by Thulaja, Naidu Ratnala, National Library Board, Singapore
• Averrhoa bilimbi - Wikipedia

References :

• The Concise Flora of Singapore : Gymnosperms and Dicotyledons by Hsuan Keng 1990, Singapore University Press