22 September 2018

Three Helens

Three Helens
Featuring the Helen butterflies of Singapore

A Great Helen feeding on the yellow cultivar of Ixora javanica

The genus Papilio features a number of large and showy swallowtail butterflies. Some are tailless (despite being referred to as swallowtails), whilst many of them have spatulate tails at vein 4 of the hindwing. Amongst the Papilio species, are the "Helens" - large black and white butterflies whose wingspan measurements range from 120mm to 150mm. These Helens are attractive and eye-catching butterflies that prefer to stay in the sanctuary of the forested nature reserves and are hence forest-dependent species.

A Blue Helen puddling at a sandy streambank in the nature reserves 

In Singapore, only one of the Helen butterflies was listed on the early authors' checklists - the Great Helen (Papilio iswara iswara). However, over the years, two more species joined the Great Helen, and on record, we now have the Blue Helen (Papilio prexaspes prexaspes) and the Red Helen (Papilio helenus helenus) in Singapore. The Blue Helen is rare, but regularly seen, suggesting that it is now 'naturalised' and a sustainable colony has established in Singapore. The Red Helen, however, is recorded from only a single individual spotted in 2014, and its status is considered a vagrant or seasonal migrant, despite being very common in Malaysia, compared to the Blue and Great Helens.

The Great Helen (Papilio iswara iswara)

The Great Helen is the largest species of the three Helens found in Singapore, and often spotted flying at treetop level in the forested nature reserves. When the Yellow Saraca (Saraca thaipingensis) is in bloom, one can sometimes observe the Great Helen feeding greedily at the yellow flowers of this tall forest tree.

A male Great Helen at rest.  Note the lack of the red-ringed black ocelli at the tornal area of the hindwing

This species is also often seen feeding at the flowers of the red and yellow cultivars of the Javanese Ixora (Ixora javanica) along the fringes of the nature reserves where these shrubs are cultivated. The Great Helen is also attracted to flowering Spicate Eugenia (Syzygium zeylanicum) shrubs. Although the butterfly has been seen puddling in Malaysia, it is rarely observed to engage in puddling activity in Singapore.

A female Great Helen at rest.  Note the two large red-ringed black ocelli at the tornal area of the hindwing 

The Great Helen has a wingspan of about 130 - 150mm and the female is usually larger of the two sexes. The wings are predominantly black and the forewing of the female features white post-discal streaks, reaching the termen. Both sexes feature a large white patch on the hindwing which starts from vein 4 all the way to the apex.  The female has large black ocellus ringed with red in spaces 1a and 2 on the upperside of the hindwing. On the underside, there are blue lunules in spaces 2,3 and 4.

The Blue Helen (Papilio prexaspes prexaspes)

A male Blue Helen puddling at a sandy streambank

Another black and white species, the Blue Helen was considered a new discovery when it was spotted in the 1990's. It was absent from the checklists of the early authors and collectors and was documented as a new record for Singapore. It is likely that the species migrated from Malaysia, and has since colonised areas within the nature reserves.

A Blue Helen feeding at the flower of the Spicate Eugenia

Males of the Blue Helen are observed puddling at damp sandbanks and forest trails. At other times, they can be seen feeding at the flowers of the Chinese Violet (Asystasia gangetica) and at Lantana and Ixora bushes. The Blue Helen is considered rare and usually individuals are sighted in the forested nature reserves.

The wings are black with a white discal patch that extends into space 4. There are no red ocelli on upperside of the hindwing. On the underside of the hindwing, there are narrow yellow and blue submarginal lunules, but in some individuals some of these lunules are obscure or obsolete.

The Red Helen (Papilio helenus helenus)

A Red Helen puddling at a sandy streambank

This species was a recent discovery that was added to the Singapore Checklist only in 2014 when a pristine individual was sighted feeding on the flowers of Ixora in south-western Singapore. Recorded as a vagrant or seasonal migrant, we can only speculate that the butterfly may have been carried over to Singapore by prevailing winds. The Red Helen should be looked out for in future. A common, and sometimes abundant species in Malaysia, it is a mystery as to why it did not migrate to Singapore and colonise the nature reserves like its rarer close cousin, the Blue Helen, did.

The Red Helen is often encountered puddling on damp sandy streambanks and muddy forest paths in Malaysia. Several individuals can sometimes be encountered at their favourite puddling grounds, in the company of many other Papilionids, Pierids and species of other families.

The Red Helen is similar in general appearance to its two cousins, however, the discal white patch on the hindwing is more restricted and does not extend beyond space 3. There is a full series of red submarginal lunules on the underside of the hindwing, from the tornus to the apex.

Four Red Helens and a Common Mormon puddling

We hope that in future, these Helen species will continue to be seen in Singapore, and the colonies of the Great and Blue Helens will be sustainable. The Red Helen, being a common species in Malaysia, may one day be counted as a permanent resident in Singapore, if the conditions and habitats that it prefers are ideal to support a local population.

Text by Khew SK : Photos by David Ho, Khew SK, Henry Koh, Loh Mei Yee, Nelson Ong, Simon Sng, Nicholas Tan, Tan CP and Mark Wong

16 September 2018

Taxonomic Classification in Butterflies

Taxonomic Classification in Butterflies
What is a Subspecies?

The Swedish naturalist, Carolus Linnaeus (Carl von Linne) pioneered the internationally recognised naming system for every creature and plant. Realising that every organism should be classified systematically according to its relationship with other organisms, he created the Linnaean system in his works, Systema Naturae in 1735 - a catalogue of the names of all known animals and plants. The 10th edition of Systema Naturae in 1758 is often adopted as the starting point for biological classification of animals and plants by family, genus and species.

According to the Linnaean system, all animals and plants are known by a combination of two names - the first indicating the genus, and the second, the species. This system, referred to as binominal nomenclature is also applied to the naming of butterflies. Furthermore, classification of butterflies used by many researchers and authors extend one more level to a rank below species. This is the subspecies. This method of naming the subspecies is known as the trinominal system and is now in general use for the scientific naming of butterflies.

A Pea Blue in Singapore is also known as a Long-Tailed Blue in Australia and Europe.  But its scientific name, Lampides boeticus, is consistent, wherever it is found.

I have sometimes been asked about what a subspecies is, and how a butterfly subspecies comes about. This blogpost discusses the definition of subspecies, and the way it is applied to the scientific naming of butterflies. Although most amateurs and hobbyists prefer to use English common names for butterflies, this can often be confusing, and common names tend to differ amongst different countries and published references. Scientific names, however, are adopted universally and Lampides boeticus is the name used for the species, whether in England or in Singapore. The English common name, however, may vary from Long-Tailed Blue to Pea Blue, depending on where the butterfly is sighted!

Before we examine the concept of subspecies, let's consider what makes a species. A species is a group of living things with very similar traits that can interbreed. For example, elephants can breed with each other, but not with hippopotamuses. Different species rarely interbreed. On the occasions when they do, either by human intervention or naturally, the offsprings of the interbreeding are typically sterile, and are unable to reproduce further.

By definition, a subspecies is an individual or a group within a species that has become somewhat physically different from the species. However, they are still biologically similar enough to interbreed with individuals of the same species. Now let's take a look at why some species branch into subspecies. One major reason for this is the geographic isolation of a particular population of that species e.g. by physical distance or geographical separation, like an island. They are still the same species, but the group that became isolated may take on some different physical features simply due to their location.

The southern Malaysian and Singapore subspecies malayana (left) has less dense striations on its wings than the northern Malaysian subspecies nina (right)

However, we need to understand that the science of taxonomy is ever-evolving. Scientists often find themselves in disputes about which genus a particular species belongs to, or whether two or more butterflies with very similar physical characteristics should be classified as separate species or as subspecies. With recent developments in microbiology, phylogenetics, DNA sequencing, and the study of the early stages of a butterfly often results in new insights on the relationships between species. This newfound knowledge regularly results in the necessity to make revisions to the adopted classifications of butterflies.

Scientific name of the Lime Butterfly is :
[Genus]Papilio [Species]demoleus [Subspecies]malayanus

In the trinominal system of naming of butterfly species, we have the [Genus] followed by the [species name] and then by the [subspecies name]. Hence for a Lime Butterfly, the scientific name would be Papilio demoleus malayanus. Note that only the genus name is capitalised. The species and subspecies name should never be capitalised.

Different subspecies of butterflies found in Singapore vs those found in Northern Thailand
Top : Moduza procris procis (Chiang Dao) vs Moduza procris milonia (Singapore)
Middle : Cheritra freja friggia (Singapore) vs Cheritra freja evansi (Chiang Dao)
Bottom : Lexias pardalis jadeitina (Chiang Dao) vs Lexias pardalis dirteana (Singapore)

For amateur observers (and even for the more knowledgeable enthusiasts), it is sometimes difficult to ascertain the physical differences between two subspecies of butterflies. Very often, purely due to geographical distances, a butterfly that shows very little perceptible physical differences is given a different subspecies name. Others, however, are more obvious where the physical differences are clear.

Examples of butterflies which has only the species name, suggesting that the physical appearance of these species have no significant differences irrespective of where they are found - Lampides boeticus (Pea Blue), Acreae terpsicore (Tawny Coster), Udaspes folus (Grass Demon) and Plastingia naga (Chequered Lancer)

Then what about butterflies with only species name given to it? This suggests that the species is consistent throughout its range and there are no discernible physical differences in its appearance, no matter where it is geographically found. Some examples of such butterflies that are extant in Singapore are the Pea Blue, Grass Demon, Tawny Coster and Chequered Lancer. Interestingly, quite a number of butterflies that have been described down to only species level are from the Lycaenidae and Hesperiidae families.

Left : Subspecies malayana and Right : subspecies parkeri are both found in Singapore

Left : Subspecies bolina and Right : subspecies jacintha are both found in Singapore

Left : Subspecies pratipa and Right : subspecies bisaltide are both found in Singapore. However, subspecies pratipa has not be reliably seen since 2007.

Left : Female subspecies bisalitide and Right : subspecies pratipa showing their differences on the upperside of their wings

In Singapore, there are 3 occurrences of butterflies of which there are two subspecies observed here over the years. These are the Knight (Lebadea martha parkeri and Lebadea martha malayana), the Great / Jacintha Eggfly (Hypolimnas bolina bolina and Hypolimnas bolina jacintha) and the Autumn Leaf (Doleschallia bisaltide bisaltide and Doleschallia bisaltide pratipa). Being an island separated from mainland Malaysia, it is likely that these subspecies' range overlap between Singapore and Malaysia and the evolution of the subspecies may continue until one is eventually eliminated.

Top : Caterpillar of the Autumn Leaf subspecies bisaltide and Bottom : subspecies pratipa

In the case of the Autumn Leaf, the subspecies pratipa which is usually found in Malaysia has a distinctively different caterpillar that is more obvious than the adult butterflies. However, subspecies pratipa was last seen in Aug 2007 at the Mandai Zoo and it is unknown if this subspecies still occurs in Singapore. The other two species continue to have sightings of their respective subspecies to this day.

As taxonomic science continues to evolve, technical methods and new knowledge are gained, it is inevitable that changes and updates to the scientific names of butterflies will continue.

Text by Khew SK : Photos by James Chia, Khew SK, Anthony Wong and Mark Wong

08 September 2018

Butterfly of the Month - September 2018

Butterfly of the Month - September 2018
The Chocolate Demon (Ancistroides nigrita maura)

A Chocolate Demon sends its exceedingly long proboscis deep into the flower of the Torch Ginger for nectar

Just into the ninth month of 2018, Chinese communities prepare for the Mid-Autumn or Mooncake Festival towards the end of September. Many Chinese/Asians all over the world - crazy, rich or otherwise, look forward to the sweet treats in the form of mooncakes. Even in early September, I have already had my first taste of mooncakes sold by ever-enterprising retailers who start selling these diabetes-inducing desserts way ahead of the Mooncake Festival.

Over in Jakarta and Palembang, the 18th Asian Games drew to a close on 2 Sep, with just over two weeks of competitions amongst the best athletes in Asia. The Games closed without any major hitches or security issues, as Indonesia showed its proficiency and confidence to host a major sports event and could be a contender for the Summer Olympics some time in the future. Little Singapore ended the games in 14th spot (out of 46 participating asian countries) securing 22 medals with 4 golds coming from swimming, sailing and contract bridge.

Over in Japan, Mother Nature's wrath came in the form of typhoon Jebi, the strongest winds to hit Japan in 25 years. Before it made landfall, the storm had sustained winds of 140 kilometers per hour and gusts of 165 kmh, the equivalent of a Category 1 Atlantic hurricane. And as the Japanese were recovering from Jebi, a 6.7 magnitude earthquake struck the island of Hokkaido. It is just the latest of a number of natural disasters to hit the country, continuing a summer of chaos that has seen deadly floods, typhoons, earthquakes and heatwaves. Not a good year for Japan.

A Chocolate Demon feeding on the flower of the Snakeweed

Back home in quiet, 'boring' but safe Singapore, the government had to settle for a deferment of the High Speed Rail (HSR) project that was originally touted to start operations in 2026. However, the deferment would mean that if the project will eventually happen, it would only start running in 2031. The new Malaysian government has also thrown a number of controversial bilateral proposals our way, one of which stirred the environmentalists' hornet's nest. The proposal of a 3rd terrestrial link via Pulau Ubin irked the nature community. Let us hope that this is just another 'distraction' thrown our way to mask the 'real' agenda that is yet to come.

A Chocolate Demon perches on a leaf under the shade with its wings folded upright

Let us turn to our Butterfly of the Month for September 2018. In our butterfly world, not every species is endowed with awe-inspiring beauty, colour, size or shape. Some butterfly species can appear drab and uninteresting to many observers. Our feature butterfly this month is one of them - the Chocolate Demon (Ancistroides nigrita maura).

One of the remarkable features of the Chocolate Demon is its very long proboscis

The Chocolate Demon is a relatively common species, often found in urban parks and gardens where its preferred caterpillar host plant, the Torch Ginger (Etlinger elatior) is cultivated. Several other of its caterpillar host plants are cultivated as garnishing or ingredients for our local cuisine, and hence found in urban areas.

The Chocolate Demon butterflies are often found in the vicinity of its host plant, the Torch Ginger.  They feed on the flower of this ginger, and sometimes many individuals are seen feeding together  How many Chocolate Demons can you count in the last photo?

It is a large skipper of the Hesperiidae family, and flies with an erratic and hopping flight amongst low shrubbery. It can often be observed to be feeding on various nectaring plants, and stops with its wings half-opened in a typical Hesperiidae fashion. Adults are also regularly seen in the vicinity of Torch Ginger groves, feeding on the large pink flowers of the plant. Sometimes up to half a dozen individuals can be seen together.

The Chocolate Demon is dark chocolate brown on the upperside and unmarked. On the underside, the marginal areas of both wings appear paler than the ground colour. A remarkable feature of this species is the extreme length of its proboscis, with which it uses to probe deep into flowers for nectar. The proboscis is more than twice as long as the butterfly's body.

Besides feeding on flowers for nectar, the Chocolate Demon can sometimes be seen to feed on bird droppings and other animal excretions, although it is rarely seen to puddle at damp forest paths. It can be skittish at times and sometimes 'jump' at the flash when photographed.

Caterpillars are usually found in leaf shelters on the preferred host plant, Torch Ginger. Other known host plants on which the caterpillars have been successfully bred in Singapore are Hedychium coronarium (White Ginger Lily, Butterfly Ginger), Zingiber officinale (Ginger) and Alpinia aquatica (Aquatic Ginger).

Text by Khew SK : Photos by Alan Ang, Goh EC, Federick Ho, Huang CJ, Khew SK, Michael Khor, Koh CH, Loke PF, Bobby Mun and Zhou Boyi