23 May 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

16 May 2015

Larval Host Plant for Butterflies: The Wild Cinnamon

Butterflies' Larval Host Plants #1
The Wild Cinnamon (Cinnamomum iners)

This 1st instalment of our Butterflies'  Larval Host Plants series features a species of the family Lauraceae, Cinnamomum iners. The genus Cinnamomum comprise over 300 species in tropical and subtropical regions. Due to the presence of aromatic compounds  in leaves and barks, a number of notable Cinnamomum  species have commercial value as spices: 1) Indian bay leaf comes from the species  C. tamala; 2) camphor is derived from C. camphora; and 3) cinnamon is made from inner barks of several species including C. verum (true cinnamon)  and C. iners (the subject of this article).

C. iners is widely planted as ornamentals or as hedges in gardens and parks in Singapore, likely due to its attractive foliage when there is a growth of new leaves of red and pink,. It is native to the Malaya peninsula, Singapore and India, but can be commonly found across the tropical regions. In Singapore, besides gardens and parks, this plant can be found in secondary forests, forest edges, and wastelands.

Plant Biodata :
Family : Lauraceae
Genus : Cinnamomum
Species : iners
Synonyms : C. initidum, C. paraneuron
Country/Region of Origin : Tropical Southeast/South Asia
English Common Names : Clove Cinnamon, Wild Cinnamon
Other Local Names :  Kayu Manis, 大叶桂 , 野樟树
Larval Host for Butterfly Species: Graphium sarpedon luctatius (Common Bluebottle), Chilasa clytia clytia (Common Mime), Cheritra freja frigga (Common Imperial).

Left: A wild cinnamon tree on the hillside at Mount Faber. Right: A wild cinnamon tree in the Japanese Garden.

An evergreen, small to medium-sized tree that grows up to 18 m tall, the Wild Cinnamon features ovate-oblong leaves ranging from 8 to 30cm long. The thin and leathery leaves are simple and 3-nerved at base (having three longitudinal veins) and are arranged in opposite pairs. New leaves appears twice or more in each year. The young leaves are initially reddish pink.

The reddish pink young leaves.

Maturing leaves as the reddish coloration fades away.

The reddish and light green young leaves showing the three longitudinal veins.

The maturing leaves are soft and drooping, and light green in colour. Fully matured leaves are stiff and dark green. Traditionally, the leaves  have medicinal uses as treatments for diarrhea, coughs, fever and rheumatism, and as an antidote for poisoning by the latex from the Poison Arrow Tree.

Drooping young/maturing leaves.

Mature leaves of the Wild Cinnamon.

Flowers of the Wild Cinnamon are small, creamy white to yellow and occur in panicles (much-branched inflorescence). These bisexual flowers attract insects such as bees, hoverflies and small beetles to act as pollinators in the reproduction process.

Panicles of flowers of the Wild Cinnamon.

Close up view of the flower buds.

Close up view of the creamy yellow flowers.

The small berry-like fruits are round to oblong, about 1.5x1 cm. They are initially green, but turn dark blue to purple when ripe.

Bunches of fruits of the Wild Cinnamon.

Left: young fruit; Right: mature fruit of the Wild Cinnamon.

In Singapore, the Wild Cinnamon also serves as the larval host plant for three butterfly species: Common Mime, Common Bluebottle and  Common Imperial. The first two are swallowtail species, while the last one is a lycaenid.

A Common Mime butterfly.

A Common Bluebottle butterfly.

A Common Imperial butterfly.

Eggs of these three butterfly species are typically laid by the mother butterfly on the stem/leaves of a young shoot of the Wild Cinnamon, usually when the plant still at the sapling stage, at low heights (knee height to chest level).

A female Common Mime butterfly laying an egg on the underside of a young leaf of the Wild Cinnamon in a wasteland just outside the Dairy Farm Nature Park.

A female Common Bluebottle butterfly laying an egg on the stem of a young shoot of the Wild Cinnamon in the Southern Ridges.

A female Common Imperial butterfly laying an egg on a young leaf of the Wild Cinnamon in the Southern Ridges.

Left: eggs of the Common Mime; Right: an egg of the Common Bluebottle, found on young shoots of the Wild Cinnamon in a western wasteland.

Caterpillars of all three species feed only on young leaves of the Wild Cinnamon, and avoid the fully mature leaves altogether. When resting between feeds, caterpillars of both Common Mime and Common Bluebottle position themselves on the upperside of the leaf, and are thus relatively easy to spot. As a lycaenid, one might expect to find caterpillars of the Common Imperial in the company of attending ants. However, this is not the case as the Common Imperial caterpillar lacks the dorsal nectary organ and tentacular organs typically found in most lycaenid species.

Two eggs and one 1st instar caterpillar of the Common Mime found on together on a young shoot of the Wild Cinnamon in Jurong Eco Garden.

A 2nd instar caterpillar of the Common Mime resting against the mid-rib on the upper surface of a young leaf of the Wild Cinnamon.

A 5th (final) instar caterpillar of the Common Mime found on a leaf of the Wild Cinnamon in the Southern Ridges.

Early instar caterpillars of the Common Bluebottle found on the upperside of young leaves of the Wild Cinnamon in the Telok Blangah Hill Park.

4th instar (left) and 5th instar (right) caterpillars of the Common Bluebottle sighted in Mount Faber.

Caterpillars of the Common Mime typically wander away from the leaves and choose a stem/branch (not necessarily on the same Wild Cinnamon plant it feeds on) as its pupation site. Common Bluebottle caterpillars, on the other hand, could simply choose to pupate on the underside of a leaf or stem of the same Wild Cinnamon plant. In the case of Common Imperial, the pupation site is usually a spot on the stem of the same plant it feeds on.

A pupa of the Common Imperial found in the Southern Ridges.

Two views of a pupa of the Common Bluebottle on the underside of a leaf of the Wild Cinnamon.

Two pupae of the Common Mime on the same branch.

So when you are out in our parks and gardens, take a closer look whenever you encounter the Wild Cinnamon, and you may be pleasantly surprised by the sight of caterpillars or pupae of these three butterfly species, or better still, the sight of a mother butterfly doing its oviposition run. 

Text and Photos by Horace Tan.

09 May 2015

The Julia Heliconian's Samba Continues...

The Julia Heliconian's Samba Continues...
An Alien Invader's Southward Conquest

A mating pair of Julia Heliconians at the Phuket Butterfly Farm, Thailand

Some time back in 2009, ButterflyCircle members encountered a new species, then unrecorded in the Malaysian Butterfly Checklist, on Pulau Langkawi in Malaysia. We were surprised to encounter the Dryas iulia, known by its English common name of Julia Heliconian, in Malaysia. This neotropical butterfly originates from the southern states of USA to the South American countries like Mexico, Costa Rica, Ecuador, Brazil, Peru and Bolivia.

A male Julia Heliconian at Phuket Butterfly Farm, Thailand

In my earlier article on the discovery of the Julia Heliconian, I postulated that the spread of this species would likely follow the colonisation route of two other species previously not found in Malaysia and Singapore, The Leopard Lacewing (Cethosia cyane) and Tawny Coster (Acreae terpsicore). Both these species have now fully extended their range southwards and are now resident species in Singapore, and in the case of the Tawny Coster, even further southwards to Indonesia.

Leopard Lacewing and Tawny Coster, two "exotics" that have colonised Malaysia and Singapore habitats and are now considered widespread.  Just two decades ago, these species were not found in either country.

Just about six years after the first sighting of this species on Pulau Langkawi, a recent sighting by butterfly enthusiast Tai Lung Aik in Subang Jaya in the state of Selangor in Malaysia, supports the view that the Julia Longwing will continue to extend its range southwards in Peninsula Malaysia. Several sightings of an ovipositing female Julia Heliconian and the discovery of mature caterpillars on the host plant Passiflora suberosa, strongly suggests that the butterfly is moving slowly, but surely, down south and colonising areas conducive to its survival.

A female Julia Heliconian ovipositing near its host plant, Passiflora suberosa

It would appear that the Julia Heliconian has now adapted to two non-native, but widespread host plants, Passiflora foetida and Passiflora suberosa. Both plants are invasives and grow easily in the wild. In the case of the adult butterfly and caterpillars found by Lung Aik, they were discovered on an urban roadside fence on which the host plant was growing wild. This is not a cultivated plant nor a species that is popular for its aesthetic appeal to gardening enthusiasts.

The migration route of the Tawny Coster.  Will the Julia Heliconian be found in Singapore soon?

If we trace the journey of the Tawny Coster that was previously absent from the Malaysia/Singapore butterfly fauna, it took nine years after it was first spotted in Pulau Langkawi to reach Petaling Jaya in the state of Selangor. Thereafter, it continued its colonisation southwards and reached Singapore in about four years. Given that the Julia Heliconian is an even stronger flyer and shares the same caterpillar host plants as the Tawny Coster, will be see it in Singapore even faster? Perhaps in the next two to three years? Keep your eyes peeled for this South American invader!

Late instar caterpillars of the Julia Heliconian discovered by Tai Lung Aik in Selangor, Malaysia

A scientific paper has been written about the Julia Heliconian by Noah Burg et al. The paper implies that the Julia Heliconian, now found in Southeast Asia, probably originated from a butterfly farm in Phuket. The practice of releasing butterflies at weddings and also as a religious gesture during Vesak Day (a Buddhist festival), probably aided the spread of this exotic species.

A typical fence overgrown with "weeds", one of which is the host plant Passiflora suberosa

The paper also continued to validate its thesis using DNA sequencing, and proved that the Julia Heliconian found in Thailand and Malaysia, had its origins from Costa Rica. The DNA codes correspond with the subspecies Dryas iulia modesta which had likely made its way via human agency, having been imported as an exotic species to be featured at a butterfly farm in Phuket, Thailand.

A female Julia Heliconian flutters amongst its host plant, all ready to lay eggs

There are some observers who consider the "invasion" of this exotic species a serious "feral species invasion" in Southeast Asia, and anyone who spots this species should destroy it to prevent its impact on the native species in Southeast Asia. This may be an ideal or optimistic view, but certainly a futile one. The scientific paper by Noah Burg et al mentioned, "The distribution of the species in Thailand currently encompasses thousands of square kilometers, and eradication efforts are unlikely to be successful, particularly since P. foetida (and now P. suberosa as well) is a common, invasive species, making it difficult to find all possible larval host plants for control purposes."

The Julia Heliconian's host plant, Passiflora suberosa

I concur with the authors' views on the futility of any efforts to eradicate these species. Further premeditated interventions may even unknowingly cause the inadvertent demise of other species! The authors of the paper also mentioned "It is unclear how this novel introduction will affect wild populations of other organisms. The species has been observed feeding on Passiflora foetida, which is an invasive plant in Thailand, and the butterfly might therefore be a boon for biological control of this weed."

A female Julia Heliconian shot at the Phuket Butterfly Farm, Thailand

It would be interesting to see how the Julia Heliconian, an exotic, competes for survival against two other species, themselves exotics and "alien" to Southeast Asia until the end of the last millennium. As the Julia Heliconian, Tawny Coster and Leopard Lacewing all share the same host plants, it may be a case of "aliens vs aliens" in a battle for supremacy! The two host plants themselves are "aliens" and considered weeds. So it will be an interesting ecological study for academics who may wish to pursue this topic of invasive flora and fauna battling amongst themselves to establish control over a newly colonised habitat.

It may have started with a mistake of allowing imports of butterfly pupae from different parts of the world, but there is little that we can do to eradicate this species now. Butterfly releases further aggravate the problem, as they are intentionally spread by humans into their new environment. Southeast Asian butterfly farms also export butterfly pupae to butterfly houses and farms in temperate countries. Fortunately, biological legislation and biohazard regulations help to control such "exotics" (from the point of Europe and US), from escaping and establishing new alien populations.

Mature caterpillars and pupa of the Julia Heliconian found in Selangor, Malaysia

The question that we should ask now is, what other species are butterfly farms in the region importing from South America (and elsewhere) and would the release of these species continue unabated without any controls? The authors of the paper also alluded to genetic biopollution and other pathological risks, even if species amongst countries within the region cross borders via human agency.

The Yellow Palm Dart, an "invasive species" that has its origins in Australia.  It is now found as far north as Ipoh in northern Malaysia

As it is, an Australian species, the Yellow Palm Dart (Cephrenes trichopepla) a skipper that was not known from Southeast Asia, has spread, probably due to horticultural trade, as far as the northern state of Perak in Malaysia. It has quietly and undramatically spread from its country of origin, Australia, and rapidly moved up north, as it resembles many local species and may have gone unnoticed. Its caterpillars feed on Palmae, and may be a potential pest to coconut growers.

Another male Julia Heliconian shot at the Phuket Butterfly Farm, Thailand.  Will we see this species in Singapore soon?

Coming back to our South American beauty, the Julia Heliconian, it is only a matter of time before it further establishes colonies in the southern half of Peninsula Malaysia as it heads down south to Singapore. Keep a look out for a large orange butterfly that flies rather quickly and looks quite different from any of our other extant species in Singapore.

Text by Khew SK : Photos by Tai Lung Aik and Khew SK

References : Noah A. Burg, Ashman Pradhan, Rebecca M. Gonzalez, Emely Z. Morban, Erica W. Zhen, Watana Sakchoowong, David J. Lohman Inferring the Provenance of an Alien Species with DNA Barcodes: The Neotropical Butterfly Dryas iulia in Thailand