12 October 2019

Butterfly of the Month - October 2019

Butterfly of the Month - October 2019
The Lance Sergeant (Athyma pravara helma)

A Lance Sergeant sunbathing on top of a fern

We are now into the 10th month of the year 2019, and climate change and environmental issues continue to dominate the news in the past few weeks. Besides the usual storms and typhoons making their usual rounds across the globe, the dreaded haze was back to choke several southeast asian countries again.

The last two significant haze years that were recorded were in 2013 and 2015 and a milder one in 2016. Memories of the 2013 haze, which was one of the worst in recent history, recorded a Pollutants Standards Index (PSI) of 401 in Singapore. Back then, schools were closed and the acrid odour of burning organic material hung in the air for days. Visibility was low, and the number of haze-related respiratory health cases spiked. The haze returned in 2015, albeit slightly less intense with a peak PSI of 317.

After 2015, the annual slash-and-burn farming plus the clearing of land for oil palm plantations, particularly in Indonesia, seemed to have been brought under control. In 2016, a minor haze with PSI readings in the low 100's affected Singapore again, but only for a short period before things went quickly back to normal. And as if to remind us of the spectre of choking air, the haze returned with a vengeance this year with the PSI crossing the 150 mark and the smell of burning in the air. Fortunately, the return of some wet weather helped and the air quality was back to normal after slightly more than a week.

One wonders how governments can be more effective in controlling open burning of forests in Malaysia, Thailand and Indonesia? The clearing of forests for the cultivation of commercially-beneficial crops appears to be the main cause of burning, as this is the cheapest and most expedient form of land clearance. However, the untold damage to the environment, and not to mention biodiversity, due to the fires is something that cannot be easily quantified. And so we wait with baited breath (and our N95 masks) for haze to hit us again in the coming years if things do not change.

On the global arena, teenager Greta Thunberg made the news with her impassioned plea to the governments of the world to do something about climate change, or face irreversible consequences that her generation will have to suffer in the decades ahead. Whether this will change anything, we will have to wait and see. However, planning ahead is something that Singapore is not waiting for any longer, and engineering and urban strategies are in progress to address the imminent rise in sea levels.

Our butterfly of the Month for October 2019 is the Lance Sergeant (Athyma pravara helma). This species is one of several black-and-white striped butterflies in the genus Athyma that can be found in Singapore. In an earlier article, we featured the Sergeants of Singapore, highlighting the five extant species of Sergeants that are found in Singapore.

Although recorded as a new discovery in the mid 1990's the Lance Sergeant, could have possibly been missed by the early researchers in their documentation of Singapore's butterfly fauna. It is moderately rare species, but the host plants that its caterpillars feed on are not uncommon in the forested nature reserves of Singapore. It is not rare in Malaysia - where it is widely distributed from lowland forests to sub-montane habitats like Fraser's Hill.

A Lance Sergeant feeding on the ripened fruit of the Singapore Rhododendron (Melastoma malabathricum)

The Lance Sergeant is a medium-sized butterfly with a forewing length of 24-28mm. It is black and white on the upperside, with the diagnostic unbroken cell streak that easily distinguishes it from the other lookalike species in the Athyma genus. This unbroken white streak stretches across the thorax, and ends on both sides of the forewing with a thickened club.

A Lance Sergeant puddling at a muddy footpath

The underside is a greyish-brown and similarly marked as in the upperside, with the basal area of both wings a dirty green. The compound eyes are transparent, whilst the underside of the antennae club is orange in colour, but black on the upperside. The Lance Sergeant is often encountered feeding on flowers of forest trees, fruits but is also as regularly observed puddling at damp muddy footpaths.

The life history of the Lance Sergeant has been successfully recorded in Singapore. The host plants documented are two species from the genus Uncaria. These plants have a characteristic pair of cat-like claws which are modified lateral branches at the base of the leaves. The pupa of the species has a golden metallic appearance that is reflective and at certain angles, makes the pupa appear to be empty.

Text by Khew SK : Photos by Khew SK, Nelson Ong, Horace Tan and Anthony Wong

05 October 2019

Leafy Disguises

Leafy Disguises
Masquerade mimicry in Butterflies

An Orange Oakleaf (Kallima inachus siamensis) puddling

Certain species of butterflies adopt various means and ways to fool predators so that they can avoid being attacked and ending up as some other animals' lunch. In previous blogposts, we saw some survival strategies that are employed to avoid predation. These vary from aposematic colouration, mimicry, camouflage, crypsis, masquerade and decoy tactics. In this weekend's blogpost, we take a look at how certain species of butterflies mimic dead leaves to avoid being detected by predators.

Amongst Asian butterflies, a small number of species have evolved and adapted to resemble dead leaves as they hide amongst vegetation to avoid being spotted. Amongst the most well-known are the ten or so species from the genus Kallima. Collectively called the Dead Leaf, Oakleaf or Leaf butterflies, these species masquerade as dead leaves when their wings are folded upright.

A Leaf Butterfly (Kallima limborgii amplifura) in Penang

These species adopt the strategy known as masquerade mimicry whereby the butterfly's wing has evolved to promote concealment through protective imitation of other benign objects. Masquerade mimicry is considered a slightly different tactic of concealment from crypsis because it "obstructs recognition rather than avoids detection" (Natural Selection and Beyond : The Intellectual Legacy of A.W. Wallace, Oxford University Press, 2008)

Bornean Leaf Butterfly (Kallima limborgii buxtoni) under and upperside

Of the Kallima species, The Leaf Butterfly (Kallima limborgii amplifura) flies in Malaysia. References indicate that this species was found in Singapore prior to the 20th century but is considered extinct today. However, the Leaf Butterfly is not rare in Malaysia and southern Thailand, where the subspecies limborgii flies. Further up north in Thailand and across to India, a species called the Orange Oakleaf (Kallima inachus) can be commonly found. Over to the west, in Sumatra, the species Kallima paralekta is the native species, whilst over in Borneo, the species Kallima buxtoni is found. (In some literature, this species is considered the subspecies buxtonii of Kallima limborgii rather than a distinct species)

Leaf Butterfly (Kallima limborgii amplifura) under and upperside

In the field, encounters of various species of the Kallima species are often in the shaded forest understorey. These large butterflies tend to forage amongst leaf litter or puddling at muddy footpaths. They perch with their wings folded upright, masquerading amongst the dead leaf litter to conceal their presence. At times, they flap their wings open and shut, displaying their attractive and colourful uppersides.

An Orange Oakleaf perched on a tree trunk.  Complete with leafy look, mid-rib, leaf stalk and "fungus" spots on its wings

The evolution of the Leaf Butterfly is such that the wings resemble a dead leaf - complete with curved wingtips, a prominent "mid-rib", to the leaf stalk in an adaptation of the tornal area of the hindwing, secondary leaf veins and even blemishes and fungus on the wings! When it perches on a twig or the trunk of a tree, it masquerades as an innocuous dead leaf and makes itself difficult to spot.

The upperside of the wings is a different matter altogether. It is likely that this amazing display of colours and iridescent blue scaling is meant to attract a mate or call attention to itself when there are reasons to do so. Although the butterfly remains effectively camouflaged when it chooses to, there are times when it is seen to open its wings to sunbathe and in the process, probably tempting fate if there are potential predators lurking around.

Orange Oakleaf (Kallima inachus siamensis) under and upperside

Articles on the Internet have alluded to dry and wet season forms of Kallima where the patterns and colours of both the upper and undersides of the butterfly's wings are different, to match the ecological and environmental characteristics of the weather's effect.

Autumn Leaf - under and uppersides

There are several other species of butterflies that have adopted masquerade mimicry and attempting to resemble dead leaves, but none are as effective or successful as the Kallima species. However, an associated species, the Autumn Leaf (Doleschallia bisaltide), which flies locally in Singapore and is quite a geographically-widespread species across Asia, is considered a good example.

Variations in colouration of the Autumn Leaf

The Autumn Leaf adopts a similar strategy of resembling a dead leaf with a mid-rib, leaf stalk and blemishes and patterns that can be considered a good mimic of a dead leaf. When perched amongst leaf litter or shrubs, this adaptation is quite successful in camouflaging the butterfly from the eyes of a would-be predator.

Although the Leaf Butterfly was once recorded in Singapore, it is now considered extinct. Hopefully, it will one day make its return to this little island and make its home here once more.

Text by Khew SK : Photos by Antonio Giudici and Khew SK

28 September 2019

Singapore's Royalty - Part 2

Singapore's Royalty - Part 2
Featuring the Royal Butterflies of Singapore

A male Banded Royal opening its wings to sunbathe at Bt Timah Nature Reserve

In this second part of our weekend's feature blogpost, we introduce the rarer species of "Royal" butterflies found in Singapore. In Part 1, we introduced the 4 "Royals" - Peacock, Felder's, Chocolate and White. Those species, though considered moderately uncommon, are more likely to be spotted by butterfly watchers and enthusiasts as they are widely distributed and sometimes frequent urban parks and gardens.

An Influent Royal feeding on the fruits of Singapore Rhododendron

This weekend's blogpost features some of the rarer "Royals" - some of which have been observed only a handful of times in Singapore over the past two decades. Of the five species featured, 4 are from the subfamily Theclinae of the Lycaenidae family and with the only exception from the subfamily Heliconiinae of the Nymphalidae family.

5. The Banded Royal (Rachana jalindra burbona)

The Banded Royal has often been observed to perch upside down on the underside of a leaf to rest

A species that was re-discovered in 2006 in the Central Catchment Nature Reserves, the Banded Royal is a species that has been observed more regularly than the other rare species featured in this blogpost. A fast-flying butterfly, the Banded Royal is occasionally spotted feeding at the ripened fruits of the Singapore Rhododendron (Melastoma malabathricum). Males are known to appear from time to time, perched on the tops of leaves or sunbathing with their wings partially open.

The male is a deep shining blue above with narrow black borders. The female is a drab brown above with some black spots at the hindwing tornal area. The underside is white with a broad brown distal border where the inner half is a darker brown. The hindwing has two tails at veins 1b and 2. One of the black tornal spots is orange-crowned and some blue scaling along the tornal area. The eyes of the Banded Royal are jet-black.

A Banded Royal feeding on the ripened fruit of the Singapore Rhododendron

The caterpillar host plant is likely to be a parasitic plant like Macrosolen cochinchinensis or one of the Loranthus spp that many of these rarer Theclinae's caterpillars tend to favour. Its life history has not been successfully recorded yet in Singapore.

6. The Influent Royal (Tajuria dominus dominus)

An Influent Royal perches on the flowers of the Bandicoot Berry

This Royal is considered very rare in Singapore and is the smallest of the three Tajuria species currently recorded in Singapore. It was first re-discovered in 2006 at Alexandra Hospital's Butterfly Trail, feeding on the ripened fruits of the Singapore Rhododendron. Subsequently, it was spotted sporadically over the years when its caterpillars or pupae were discovered and bred to adulthood. It is a rapid flyer and probably prefers to remain at the treetops.

The name "Influent Royal" was christened by Pisuth Ek-Amnuay in the Butterflies of Thailand books, although the origin of the English name is curious. The meaning of influent refers to "a stream flowing into another stream." Or perhaps the author is trying to refer to influent to mean influential? For the time being, we will use this common name until some other more logical or apt name is coined for this species.

An Influent Royal feeding on the ripened fruit of the Singapore Rhododendron

The male is bright blue above with a deep black visual brand at the end of the forewing cell. The forewing has a broad black apical border like many of the other species in the genus. The underside is a drab grey with the post-discal stripe placed closer to the cell than the termen. The two black tornal spots are orange-crowned, with the orange coalesced into a large tornal patch. There are two white-tipped tails and veins 1b and 2 on the hindwing.

7. The Silver Royal (Ancema blanka blanka)

The upperside of a male Silver Royal

The Silver Royal has been seen only a few times in Singapore, but at least twice at the Southern Ridges hill tops. It was a re-discovery in 2005 when it was spotted feeding at the flowers of a Syzygium tree. A fast-flying species, it is usually skittish and probably prefers treetop habitats unless individuals descend to the lower shrubbery to feed or oviposit.

The male of the Silver Royal is a bright shining blue with broad black forewing borders and darkened veins on both wings. The female is a lighter shade of blue and has rounder wings. The underside is distinctive of this species and sports a silvery sheen when light shines at a certain angle on the wings. There are two prominent black tornal spots that are orange-crowned and there are two tails at veins 1b and 2 on the hindwing.

A Silver Royal puddling at a damp footpath

The species is sometimes observed to puddle at damp roadside paths and males are seen to occasionally opens its wings to sunbathe, showing the blue splendour of its iridescent wings. The caterpillar host plant is likely to be a parasitic plant but its life history has hitherto not been recorded in Singapore yet.

8. The Golden Royal (Pseudotajuria donatana donatana)

A Golden Royal perches on the buds of Javanese Ixora

Another re-discovered species in Singapore in 2005, the very rare Golden Royal (also known as the Dawnas Royal) has only been spotted no more than 3 times in Singapore. First spotted at a reservoir park, the species has proven to be extremely elusive although it is by no means considered a vagrant or a seasonal visitor.

The male Golden Royal is a shining blue above with broad black borders on both wings. The female is of a lighter blue with the colour confined to the wing bases only. The underside is a rich golden yellow and unmarked on the forewing. The hindwing has a pair of black tornal spots and edged generously with metallic green scales. There are two white-tipped tails at veins 1b and 2 on the hindwing.

It is also observed puddling at damp streambanks and footpaths at times. The caterpillar host plant is unknown in Singapore, although it is likely to also depend on parasitic plants for its early stages.

9. The Royal Assyrian (Terinos terpander robertsia)

The last of our "Royals" has the name royal as a prefix to its common English name, unlike the 8 preceding species. The sole representative of its genus in Singapore, the Royal Assyrian is moderately rare and is a forest-dependent species that is rarely seen outside the forested nature reserves of Singapore. It has a habit of resting on the underside of leaves with its wings folded upright. At certain times of the day, it may be seen sunbathing with its wings opened flat, showing off its majestic purple uppersides.

The Royal Assyrian is rich purple above with a white patch on the hindwing. The underside is purple-brown with a series of reddish-brown and pale blue stripes crossing both wings. The hindwing also features a series of large orange-ringed post discal spots.

A Royal Assyrian puddling at a damp walkway at BTNR

The species has been successfully bred on the host plant Rinorea anguifera which can be found growing mainly in Singapore's forested nature reserves. The Royal Assyrian can sometimes be spotted puddling at damp footpaths and sandy streambanks in forested areas.

And that completes our introduction to all the Royal butterflies of Singapore.  I am sure that one day, there will be a few more Royals to add to our checklist, but that will be another story for another time.

Text by Khew SK : Photos by Khew SK, Jonathan Soong, Tan Ben Jin and Horace Tan

22 September 2019

Singapore's Royalty - Part 1

Singapore's Royalty - Part 1
Featuring the Royal Butterflies of Singapore

A Chocolate Royal basks in the sun with its wings opened to show the majestic purple uppersides

This weekend's blogpost takes a look at the various butterfly species found in Singapore that bear the English common name "Royal". The word royal is often defined as "used to indicate that something is connected with a king, queen, or emperor, or their family." In describing something as royal gives it a complimentary stature of being beautiful, majestic or an object of exceedingly high recognition.

In our butterfly world, quite a few species have been christened with the "royal" title. In most of them, the name is certainly befitting of their beauty and awe-inspiring colours. The Singapore species that bear the name "Royal" are largely from the sub-family Theclinae of the family Lycaenidae. Part 1 of this blogpost introduces four of the more frequently encountered species in Singapore.

1. Peacock Royal (Tajuria cippus maxentius)

A Peacock Royal perches on a bed of red Ixora flowers

The Peacock Royal is the commonest of the "Royals" and is widely distributed in Singapore. It can regularly be found in urban parks and gardens but is sometimes seen in the forest edges of the nature reserves of Singapore. Both males and females are observed with regularity, especially when feeding on the red flowers of the Javanese Ixora.

Upperside of a male (top) and female (bottom) Peacock Royal

The upperside of the male Peacock Royal is a beautiful royal blue with a broad black apical border on the forewing. The female is pale blue with broad black apical borders on the forewing and a series of black squiggly post-discal striae on the hindwing. The underside of both sexes is greyish-white with post discal striae and series of marginal and sub-marginal spots. The large black tornal spots on the hindwing are orange-crowned. The hindwing features a pair of white-tipped tails at veins 1a and 2.

The Peacock Royal is skittish and a fast flyer. It has jet-black eyes which can immediately distinguish it from its other related cousins in the genus. The caterpillar of this species feeds on parasitic plants like Dendropththoe pentandra and Macrosolen cochinchinensis,both of which are common in urban gardens.

2. Felder's Royal (Tajuria mantra mantra)

Our next royal is the Felder's Royal. This species comes from the same genus as the Peacock Royal and is a moderately rare species. It is widely distributed across the island and shares the same caterpillar host plant as the Peacock Royal. Individuals of the Felder's Royal are typically larger than the related species in the genus.

The upperside of the male is a shining greenish blue whilst the female is a pale purplish blue. Both sexes have a broad black apical border on the upperside of the forewing. The underside is a drab greyish brown and are whitened at the dorsum. Each hindwing has a pair of white-tipped tails at veins 1b and 2. The tornal area has iridescent blue scales flanked by two orange-crowned black spots.

Also a skittish flyer, the Felder's Royal has a habit of perching on the underside of a leaf to rest or hide itself. The compound eyes are transparent and silvery grey. It has been successfully bred in Singapore on the parasitic plant Macrosolen cochinchinensis.

3. Chocolate Royal (Remelana jangala travana)

The Chocolate Royal is another moderately rare species in Singapore. It makes an appearance during certain months of the year, but then may be absent for many months of the year. Its host plants are Eurya acuminata and the common Ixora javanensis. Hence it is curious that it is not as common as it should be, given the abundance of its host plants.

The upperside of the male Chocolate Royal is a majestic deep purple, with broad black borders on both wings. The female is paler with the basal portions of the forewing entirely purple. The underside is a dark chocolate brown with darker narrow post-discal lines on both wings. The black tornal spots on the hindwing are crowned with metallic green scaling without any orange crowning as in the preceding two species. There are two white-tipped tails at veins 1b and 2 on the hindwing.

A Chocolate Royal puddling at a damp footpath

The Chocolate Royal is often seen flying rapidly amongst low shrubbery and feeding on the flowers of various Ixora hybrids. Occasionally, males are seen to sunbathe with its wings opened flat. The species has also been encountered puddling at muddy streambanks and damp footpaths in the forested areas.

4. White Royal (Pratapa deva relata)

The White Royal was a recent re-discovery in 2007 when it was spotted at an urban park in Singapore. The species was subsequently observed at various locations across the island, particularly in the vicinity of its caterpillar host plant, the parasitic Scurrula ferruginea.

The upperside of a female White Royal

The upperside of the male White Royal is a deep lustrous blue whilst the female is a paler sky blue. Both sexes have a broad black apical border on the upperside of the forewing. The underside is greyish white with post-discal black streaks. The hindwing tornal area has the usual orange-crowned black spots. There is a pair of white-tipped tails at veins 1b and 2 of the hindwing.

A female White Royal perches on the edge of its caterpillar host plant.  Note transparent eyes

The White Royal is skittish and fast flying, and often stays in the vicinity of its caterpillar host plant. It is considered moderately rare but when a colony is located, there are usually several individuals flying around. However, in recent years, the species has been absent and sightings have been few and far in between.

And there you have it, the more regularly seen Royals in Singapore, although none of them can be considered common. In the next part of this article, we take a look at the rarer species of Royals that have been recorded in Singapore over the past two decades.

Text by Khew SK : Photos by Khew SK, Koh CH, Loh MY, Simon Sng, Jonathan Soong and Horace Tan.