Two Blues Make it 290

Two Blues Make it 290
Update to the Butterflies of Singapore Species Checklist


The Glistening Caerulean (Jamides elpis pseudelpis)

After our last re-discovery report on the Moth Butterfly, which raised the number of butterfly species found in Singapore to 288, this update adds on two more species to the Singapore Checklist. Both these Lycaenidae were originally listed in the database of species from the early authors based on their checklists found in Butterflies of the Malay Peninsula Edition 4 by Corbet & Pendlebury, and Butterflies of West Malaysia and Singapore by WA Fleming.

The Large Four Line Blue (Nacaduba pactolus odon)

The reference checklists in C&P4 and Fleming's books form the baseline species checklists for butterflies of West Malaysia and Singapore. The journal article "Updating The Butterflies of the Malay Peninsula" in the Malayan Nature Journal in 2006, Vol 59 Part I, pages 1-49 records some of the more recent revisions. The first draft of this article was produced by Col JN Eliot just before his untimely death on 11 Apr 2003. The article was edited, enlarged and prepared for final publication by Henry Barlow, Richard Eliot, Laurence G Kirton and RI Vane-Wright - all experts in the field of butterflies of the region. This journal article adds to the baseline checklists and updates the more recent finds in Malaysia and Singapore in the later part of the 20th century and from 2000-2005.

There has been some recent confusion in the number of species for Singapore, with various authors counting subspecies as well. Based on scientific taxonomic convention in documenting species checklists, this is obviously incorrect. A species is counted only once irrespective of how many subspecies it may have. There have also been uninformed amateurs who insist on using reference books which feature butterflies of other countries in the region e.g. Butterflies of Thailand by Pisuth Ek-Amnuay, to baseline Singapore's species. This is obviously incorrect and misleading. The Thai book, which is an excellent reference for Thailand's butterfly fauna, is obviously not appropriate if used to identify Malaysian or Singaporean butterflies, in particular subspecies.

Two Re-Discovered Lycaenids recorded

Recently, ButterflyCircle members re-discovered two species from the genus Jamides and Nacaduba. These two genera feature many lookalike species which are difficult to identify from field observations. Often, only with good photos and records of the early stages of the species can the species be positively identified.

These two genera feature a number of species from the baseline checklists that have hitherto not been completely re-discovered. This is not to say that some of these species have gone extinct in Singapore, but merely a case of the difficulty of identifying them without proper scientific rigour.

Jamides elpis pseudelpis (Glistening Caerulean)

A female Glistening Caerulean ovipositing on the flowers of Saraca cauliflora

The genus Jamides features a number of species that are similar in appearance and difficult to identify when the butterflies are in flight. Occasionally, individuals are encountered puddling, ovipositing or feeding where good photos are possible, and from these, further confirmation can be made of the identity of the species. Better still, if the early stages are recorded and the caterpillars bred to adulthood.

The male of the Glistening Caerulean (Jamides elpis pseudelpis) is described to be pale shining sky blue above, with the hindwing paler and the underside markings visible from above. The pale blue female has a more prominent black tornal spot which is sometimes faintly orange-crowned. This species belongs to the elpis sub-group of the Jamides, which is characterised by the post-discal band on the hindwing beneath being completely dislocated at vein 3.

Another female Glistening Caerulean ovipositing on an alternative host plant's flower buds

The species has a wingspan of about 27-30mm where the marginal border on the upperside a thread, and the hindwing bears no submarginal markings. The upperside forewing border of the female ends at the costa.



The Glistening Caerulean was re-discovered by ButterflyCircle member Sunny Chir, after reviewing a shot of a Jamides taken at an urban park, where females were observed ovipositing on the flowers of Saraca cauliflora with another closely- related species the Sky Blue (Jamides caeruleus caeruleus) whose caterpillars also feed on the same flowers.

The early stages were recorded by ButterflyCircle member Horace Tan, and will be subject of a future blog life history article.

The Large Four-Line Blue (Nacaduba pactolus odon)



The second rediscovery belongs to the genus Nacaduba - again another genus with many confusing lookalike species. When in flight, there is no way to distinguish the numerous species that exist in Singapore. However, this species' underside markings are unique enough to be able to render identification with a higher confidence if a well-taken photograph is available.



The Large Four Line Blue belongs to the pavana sub-group in the genus Nacaduba. This sub-group is characterised by the absence of the basal pair of lines on the forewing beneath. The Large Four Line Blue is described as the commonest species in the group, and where the underside stripes are broader and more diffuse that in any other species in the genus.

This shot of a puddling Large Four Line Blue was taken at Pulau Pawai, an SAF live firing island

The male of the Large Four Line Blue is purplish blue with marginal borders of about 1.0mm thick. The female is pale blue with the distal portions almost whitish , and with broad black marginal borders of about 3-4mm thick. On the underside, the space between the post-discal straie are unicolourous and of the ground colour. The species has a wingspan ranging from 29-32mm. Both the males and females have a filamentous white-tipped tail at vein 2 of the hindwing.



The Large Four Line Blue is a fast flyer, the male particularly so, but in the later hours of the day, it flies rapidly and perches on a favourite leaf or twig, returning time and again to the same perch after flying off.

With these two re-discoveries, the Singapore Butterfly Checklist now reaches 290 species. In a forthcoming update, we will feature four more species - one of which is a new taxon for Singapore to further add to the Singapore Checklist.

Text by Khew SK ; Photos by Bobby Mun, Federick Ho, Horace Tan, Khew SK, Robin Ngiam, Sunny Chir & Tan CP

Special Acknowledgments : Dr Laurence Kirton of Forest Research Institute of Malaysia for confirming the ID of Jamides elpis.

Butterfly of the Month - August 2023

Butterfly of the Month - August 2023

The Large Fourline Blue (Nacaduba pactolus odon)

A Large Fourline Blue feeding on the flowers of the Mile-A-Minute climber

Two thirds of the year 2023 have come and almost gone, as we wind down to the last 48 hours of the month of August. Singapore has celebrated its 58th birthday, as the nation reminisces where it came from, and look ahead to where it will be in the coming decade and beyond. The month of August belongs to the astrological sign Leo. For those born between 23 July and 22 August, your zodiac sign is Leo. We featured Capricorn, Aquarius, Pisces, Aries, Taurus, Gemini and Cancer in the preceding Butterfly of the Month blogposts and will now move into the next in the series. The 12 zodiac signs are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.

Leo (♌︎) (Ancient Greek: Λέων, romanized: Léōn, Latin for "lion") is the fifth sign of the zodiac. Leo is associated with the mythological Nemean lion. The lion is a very important and prominent symbol in Greek mythology. In Greek mythology, Leo was identified as the Nemean Lion which was killed by Hercules during the first of his twelve labours. Hercules killed the Nemean Lion with his bare hands, as the lion was impervious to all weapons. This zodiac sign is often represented by fire.

Leos tend to be full of primal, creative energy. This is a sign that embodies the fire that lives within us all. Those born under the sign of Leo wants to see and be seen, just like the sun that rules it, which is why Leo is associated with visibility, attention, courage, generosity, and creative impulses. Leo's symbol, the lion, is equally telling: Lions are the kings of the jungle, known for their fierce courage and natural regality.

Leos often see themselves as born leaders and are never ready to sacrifice this power. They will try to take leadership positions in every situation no matter whether it is teamwork or family. Moreover, they can be very opinionated and find it hard to accept another person’s viewpoint. They are determined by nature, and focused on completing whatever task they start. Leo is a good friend who will protect people he loves and supports them in any life situation. Their attitude to friends is exceptional and they do not pull punches and can be very honest and direct.

One of the negative traits of Leos is arrogance. They often cross the line of simple confidence that gradually transforms into conceit and arrogance. Their belligerence and self-centredness in their pursuit of dominance and a centre of attraction does not earn them respect or win them popularity votes in certain situations. However, they will not bow down to threats and will spoil for a fight to defend their throne. 

A mating pair of the Large Fourline Blue spotted at Lornie Park Connector

Our Butterfly of the Month for August 2023 is the Large Fourline Blue (Nacaduba pactolus odon). This species was re-discovered in late 2009 and reinstated to the Singapore Checklist. One of the many lookalikes in the genus Nacaduba, the Large Fourline Blue is one of several species in the pavana group which lacks the pair of sub-basal lines on the underside of the forewing, hence having only "four" lines on the forewing.

The Large Fourline Blue is moderately rare in Singapore, but is widely distributed across the island from forest habitats to urban parks and gardens. It is the largest species of the genus and displays the typical behaviour of basking in the late afternoon sun with opened wings. At other times of the day, The Large Fourline Blue may be seen settled in the shade.

The male of the Large Fourline Blue is purplish-blue above, with marginal borders of about 1mm thick. The female is pale blue with the distal portions of the wings almost whitish, and with broad black marginal borders of about 3-4mm thick on both wings. On the underside, the striations are usually thick and more diffuse than most species in the Nacaduba genus. The hindwing features a filamentous white-tipped tail at vein 2.

A Large Fourline Blue puddling at a sandy streambank

The species can also be encountered feeding on flowering plants and bushes like the Snakeweed, Stringbush, Mile-a-Minute and others. They are quite often seen puddling at damp muddy footpaths that are tainted with organic matter. When disturbed, the Large Fourline Blue flies erratically and can be skittish. The species has been successfully bred on Entada spiralis in Singapore.

Text by Khew SK : Photos by David Chan, Federick Ho, Khew SK, Loh MY, Low JK, Aaron Soh and Horace Tan 

Life History of the Large Four-Line Blue

Life History of the Large Four-Line Blue (Nacaduba pactolus odon)

Butterfly Biodata:
Genus: Nacaduba Moore, 1881
Species: pactolus C. Felder, 1860
Subspecies: odon Fruhstorfer, 1916
Wingspan of Adult Butterfly: 32mm
Caterpillar Local Host Plants: Entada spiralis (Fabaceae)


A Large Four-Line Blue perching on a small branch in the nature reserve.

Physical Description of Adult Butterfly:

The Large Four-Line Blue belongs to the pavana sub-group (the Four-Line Blues) in the genus Nacaduba, thus it possesses the shared characteristics of lacking a basal pair of lines in the underside forewing cell. Above, the male is purplish blue with marginal black borders of about 1.0mm thick. The female is pale blue with distal portions almost whitish, and has broad black borders of about 3-4mm thick. Beneath, both sexes are greyish brown with a slight silky lustre and with the space between the post-discal straie being unicolourous and of the ground colour. The underside stripes are broader and more diffuse than the other members, with the exception of N. angusta, of the pavana sub-group. On each hindwing, there is an mid-sized orange-crowned tornal spot lightly speckled with bluish-green metalic scaling. Both sexes have a filamentous white-tipped tail at the end of vein 2 of the hindwing.

The upperside of a female Large Four-Line Blue.

Field Observations of Butterfly Behaviour:

Although there were a mere handful of sightings of individuals during one survey and 2-3 outings in the past few years, the re-discovery of this species was only recently nailed with an ID confirmation provided by Prof Konrad Fiedler. This species is uncommon in Singapore but adults have been sighted in multiple locations such as the Central Catchment Nature Reserve, Southern Ridges, western wasteland and an offshore island. The adult has an erratic but rapid flight, and typically makes its appearance in sunny weather. Encounters usually take place in sunlit spots with the adult sunbathing or flitting from perch to perch in the vicinity of its host plant.

Early Stages:

The only known local host plant, Entada spiralis, is a woody climber with bipinnate leaves, usually with 4 pairs in a pinna. This tree-topping vine can be found in the Central Catchment Nature Reserve and Southern Ridges. The early instars of the Large Four-Line Blue feed on soft tissues of the host plant such as young leaves, young stems, tendrils, and flower buds. Across its range of distribution, N. pactolus has been found to use only one plant genus (Entada) as larval host, thus it is a stenoligophagous species.

Young shoots of Entada spiralis.


Oviposition by Large Four-Line Blue females. Left: on the underside of a young leaf. Right: on flower buds.


A mother Large Four-Line Blue laying an egg on a young shoot of E. spiralis.

Eggs are laid on young shoots, flower buds and young leaves (underside) of the host plant. Each egg is pale yellowish green, circular and has a depressed micropylar area. The surface is criss-crossed with a network of ridges. Each egg has a diameter of about 0.4mm.

Two eggs of the Large Four-Line Blue. Diameter: 0.4-0.5mm.

It takes about 2 days for the egg to hatch. The young caterpillar consumes part of the egg shell to emerge. With a length of about 0.7-0.8mm, it has a pale yellowish green body with long setae (hairs) occurring dorsally and sub-spiracularly. The caterpillar assumes the typical woodlouse body shape as it grows. Both the diamond-shaped pro-thoracic shield and the anal plate are pale green.

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

The first instar lasts for 2 days and the body length reaches about 1.5mm before the moult to the 2nd instar. The long dorsal setae are absent in the 2nd instar caterpillar. The body is yellowish green and has coarser texture on its surface. The dorsum of the thorax is slightly depressed. The 2nd instar also lasts for 2 days and the caterpillar grows to a length of about 3.5mm.

2nd instar caterpillars, length: 2mm.

The 3rd instar caterpillar is still yellowish green but with a stronger emphasis in green. Faint markings in much paler yellow appear on both sides of the dorsal line. The body is also densely covered with short brown or transparent setae. Both dorsal nectary organ and tentacular organs are not unmarked and are barely distinguishable. The prothoracic shield is white with a slight greenish tinge.

3rd instar caterpillars, late in this stage, length: 6.5-7mm

After 3 days in the 3rd instar with the body length reaching a maximum about 7-8mm, the caterpillar moults to its final instar. The 4th instar caterpillar initially resembles the 3rd instar caterpillar closely. As the body grows larger in size, its colour assumes a much darker shade of green.

Two views of a 4th instar caterpillar, length: 13mm.


4th instar caterpillar. Left: Prothoracic shield; Right: Dorsal nectary organ (DNO) and
tentacular organs (TO).

The 4th instar lasts for 4 days and the body grows up to a length of about 13-14mm. On the last day of this stage, the caterpillar ceases food intake and its body shrinks in length. Once a pupation site is selected, the pre-pupatory caterpillar prepares for pupation by spinning silk threads to form a silk pad on the substrate. It then stations itself with a silk girdle across its thorax and with its rear end attached to the silk pad.

Two views of a pre-pupa of the Large Four-Line Blue

The next day, after 11-12 days of larval growth, pupation finally takes place. The pupa has the typical lycaenid shape, and is covered with short brown setae. Ground colour is pale brown, and mottled with dark brown spots of various sizes and shapes. Length of pupae: 9-10mm.

Two views of a fresh pupa of the Large Four-Line Blue

Five days later, the maturing pupa becomes increasingly darkened in the head, thorax and the wing pads. The blue patches on the forewing upperside are now noticeable through the pupal skin. The next day the adult butterfly emerges from the mature pupa.

Two views of a mature female pupa showing the markings on the forewing upperside in the wing pad.


A newly eclosed Large Four-Line Blue resting on its pupal case

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
• Notes on Host Association and Immature Biology of Nacaduba pactolus hainani, Y-F Hsu et al, BioFormosa, 34 (2), 2004, pp.61-65.
  

Text by Horace Tan, Photos by Sunny Chir and Horace Tan

Life History of the White Four-Line Blue

Life History of the White Four-Line Blue (Nacaduba angusta kerriana)

Butterfly Biodata:
Genus: Nacaduba Moore, 1881
Species: angusta H. Druce, 1873
Subspecies: kerriana Distant, 1886
Wingspan of Adult Butterfly: 30mm
Caterpillar Local Host Plants: Entada spiralis (Fabaceae)


A female White Four-Line Blue perching on a leaf near its host plant in between oviposition visits

Physical Description of Adult Butterfly:
As a member of the pavana group (the Four-Line Blues), the adult does not have a basal pair of lines in the underside forewing cell. Above, the male is purplish blue with a thin black border, about 1mm broad towards the apex; the female has broad black border on the forewing and a light blue ground colour with diffuse greyish markings on both wings. Beneath, both sexes has greyish ground colour with very broad and diffuse whitish-grey stripes. On each hindwing, there is an orange-crowned tornal spot lightly speckled with bluish-green metalic scaling. i Next to the tornal spot, a pair of filamentous white-tipped tails occurs at end of vein 2. Marginal and submarginal spots are black and stand out against the whitish bacground. The prominent rounded black sub-marginal spot in space 6 of the hindwing serves as an important identification key for this species.

A male White Four-Line Blue perching on a branch


A male White Four-Line Blue perching another branch


A sunbathing male White Four-Line Blue showing its upperside

Field Observations of Butterfly Behaviour:
Though included in the early authors' checklists for Singapore, this species has eluded the local butterfly enthusiasts in recent years before its recent re-discovery in the December 2008. Sightings have been confined to a single location where its host plant is thriving at tree top levels. The adult has an erratic flight, and typically makes its appearance in sunny weather. Encounters usually take place in sunlit spots with the adult sunbathing or flitting from perch to perch in the vicinity of its host plant.

Early Stages:
The host plant, Entada spiralis, is a woody climber with bipinnate leaves, usually with 4 pairs in a pinna. Flowers are small and occur in dense racemes. Seed pods are curled with 5-11 very large seeds to each pod. This tree-topping vine can be found in the Central Catchment Nature Reserves as well as in the Southern Ridges. Besides the White Four-Line Blue, locally this plant also plays host to the Large Four-Line Blue (Nacaduba pactolus odon), Common Line Blue (Prosotas nora superdates) and the Common Grass Yellow (Eurema hecabe contubernalis). The early instars of the White Four-Line Blue feed on young leaves of this plant by grazing away the upper layer of lamina. The later instars nibble away the lamina from the leaf edge, as well as the outer layer of young stems.


Host plant : Entada spiralis


Young shoots of Entada spiralis.


A mating pair of White Four-Line Blue


A mother White Four-Line Blue making an oviposition visit to young shoots of E. spiralis.

Eggs are laid on the young shoots of the host plant, typically in spaces between very young and yet to be unfurled leaves. It is not uncommon for a number of eggs to be found on the same shoot, however the eggs occur singly rather than in clusters. Each egg is pale yellowish green, circular and has a depressed micropylar area. The surface is criss-crossed with numerous tightly-spaced lines. Each egg has a diameter of about 0.4mm.


Two eggs of the White Four-Line Blue. Diameter: 0.4mm.

It takes 2-3 days for the egg to hatch. The young caterpillar consumes part of the egg shell to emerge. With a length of about 0.7-0.8mm, it has a pale yellowish body with long setae (hairs) dorsally and sub-spiracularly. The caterpillar assumes the typical woodlouse body shape as it grows. The body color also changes gradually to a brighter shade of yellow. A diamond-shaped pro-thoracic shield and a slight depression on the anal segment can be distinguished easily through contrasting and darker shades of coloration.


1st instar caterpillar, late in this stage. Lengths: 1.5mm (top) and 1.2mm (bottom)

The first instar lasts for 2 days and the body length reaches about 1.5mm before the moult to the 2nd isntar. The long dorsal setae are absent in the 2nd instar caterpillar. The body color is mainly yellow with a greenish undertone. The prothoracic shield is less prominent, being slightly paler than the yellow base color. The 2nd instar also lasts for 2 days and the caterpillar grows to a length of about 3m to 3.5mm.


2nd instar caterpillar, freshly moulted to this instar, length: 1.5mm



2nd instar caterpillar, late in this stage. Lengths: 2.5mm (top) and 3mm (bottom).

The 3rd instar caterpillar is still yellowish green but with an increasing emphasis in green. Faint markings in much paler yellow appear on both sides of the dorsal line. After 2 days in this stage with the body length reaching a maximum about 6-7mm, the next moult takes place to bring the caterpillar to its final instar.


3rd instar caterpillar, Lengths: 3.5mm (top) and 4.5mm (bottom)


3rd instar caterpillar, late in this stage, length: 6mm

The 4th instar caterpillar initially resembles the 3rd instar caterpillar in the day prior to the moult. However as it proceeds to feed and grow in this final instar, the body quickly takes on a much lighter shade of green with the whitish dorsal-lateral shadings more prominent than in the 3rd instar. The prothorcic shield is whitish with a few brown spots, and the dorsal nectary organ and ventacular organs are distinguishable on the posterior segments.


4th instar caterpillar of lengths: 8mm (top) and 11mm (bottom).


Body features of a 4th instar caterpillar. Left: dorsal nectary organ (DNO) and tentacular Organ (TO).
RIght: prothoracic shield.

The 4th instar lasts for 4 days and the body grows up to a length of about 11-12mm. On the last day of this stage, the caterpillar ceases food intake and its body shrinks in length. It wanders around for almost a full day before it comes to rest on a spot among leaves for pupation. The pre-pupatory caterpillar prepares for pupation by spinning silk threads to shape the leaves into a pupation shelter. Within the tight interior of the shelter, the pre-pupatory caterpillar stations itself with silk girdles and the attachment of the cremaster.


Two views of a pre-pupa of the White Four-Line Blue

The next day, after 9-10 days of larval growth, pupation finally takes place. The pupa has the typical lycaenid form, and is 8-9mm in length. It is mostly pale brown and speckled with black spots of various sizes and shapes.


Two views of a fresh pupa of the White Four-Line Blue

Six days later, the pupa becomes darkened in color signaling the imminent emergence of the adult. The markings on the forewing upperside becomes increasing obvious through the upal skin. The next day the adult butterfly emerges from the mature pupa.


Two views of a mature female pupa showing the markings on the forewing upperside in the wing pad.


Two views of a mature male pupa showing the purplish blue forewing upperside in the wing pad


A newly eclosed White Four-Line Blue resting on its pupal case


Another newly eclosed White Four-Line Blue

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 by Horace Tan, Photos by Sunny Chir and Horace Tan