Butterfly of the Month - February 2010

Butterfly of the Month - February 2010
Celebrating the Year of the Tiger

Based on the Chinese calendar, the Year of the Tiger begins on 4 Feb 2010 at 6:42am. The Tiger is the third out of twelve animals according to the Chinese Animal Zodiac signs. However, based on the Julian calendar, Chinese New Year is celebrated on 14 Feb 2010 and this is the date for which most people would associate with the dawn of the Year of the Tiger. On the Chinese elemental sign format, 2010 will be the Year of the Metal Tiger.

According to fengshui masters' predictions, drama, intensity, change and travel will be the keywords for 2010. Unfortunately, world conflicts and disasters tend to feature during Tiger years also, so it won’t be a dull 12 months for anyone. The Year of the Tiger will bring far reaching changes for everyone. New inventions and incredible technological advances have a good chance of occurring. For all of the Chinese horoscope signs, this year is one to be active – seizing opportunities and making the most of our personal and very individual talents. Everything happens quickly and dramatically in a Tiger year – blink and you could miss an important chance of a lifetime!

So it is not unexpected that we feature one of our butterfly Tigers as this month's Butterfly of the Month - The Common Tiger (Danaus genutia genutia). The Common Tiger has deep orange forewings and hindwings, with the veins strongly marked with black. There are rows of white submarginal spots on both wings and a series of larger elongated sub-apical spots on the forewings. The apical area of the forewing is black on the upperside but ranges between dark orange to a greyish orange on the underside.

A rare shot showing two forms of the Common Tiger

There are two forms of the Common Tiger. The first is form-genutia where the hindwings are unicolourous with the forewings, but usually with a slight tinge of white along the black veins. This form is usually the commoner of the two forms found in Singapore.

The orange-hindwinged form-genutia of the Common Tiger

The white-hindwinged form, or form-intermedius has the hindwings coloured white, but usually with some tinge of orange along the wing veins and also along the submarginal border. This form, which is rarer and less often seen can sometimes be mistaken for the Black Veined Tiger (Danaus melanippus hegesippus) when in flight.

A white-hindwinged form-intermedius of the Common Tiger

Males of the Common Tiger possess an oval brand containing scent scales on vein 2 of the hindwing. This is usually very obvious and can easily differentiate males from females of the species.

A male Common Tiger (top) showing the oval brand on the hindwing, whilst the female (bottom) lacks the brand

The Common Tiger is a member of the Danainae subfamily, usually called collectively as "Tigers and Crows" and which feature aposematic colouration. Due to their caterpillar host plants being predominantly lactiferous vines and shrubs, the majority of the species of this subfamily is unpalatable to predators.

The caterpillar of the Common Tiger is black and banded with white and yellow spots along its body. The IInd thoracic segment has a pair of long black-tipped crimson filaments whilst there are shorter filaments on the 2nd and 8th abdominal segments.

A photo of a Common Tiger 'cub'

The host plant in Singapore has been identified as Cynanchum tunicatum a creeper weed that is found in secondary forests, mangrove/coastal areas and even on fences in urban areas. The widespread occurrence of the host plant may be due to the way the seeds are distributed by wind.

A recently-eclosed female Common Tiger still hanging on to her pupal shell

The Common Tiger is a common butterfly species in Singapore, and is one of several "Flying Tigers" that feature prominently in many of our butterfly-friendly parks and gardens. Where the host plant is aboundant, one can often see many individuals of this species flying around. The butterfly is partial to plants like Crotalaria spp. and the Indian Heliotrope (Heliotropium indicum), Adult butterflies are also fond of stopping and resting on twigs and vines in shaded areas after a morning of feeding.

And as we herald the Year of the Tiger this coming weekend and enjoy the holidays over the Chinese New Year period, we hope that the Year of the Tiger will also bring new finds and discoveries for the Butterflies of Singapore!

ButterflyCircle takes this opportunity to wish all our Chinese readers a "Happy and Properous Year of the Tiger" and "Gong Xi Fa Cai".

Text by Khew SK ; Photos by Sunny Chir, Khew SK, Kerwin Sum, Johnny Wee, Wong CM

Life History of the Two-Spotted Line-Blue

Life History of the Two-Spotted Line Blue (Nacaduba biocellata)



Butterfly Biodata:
Genus: Nacaduba Moore, 1881
Species: biocellata C. & R. Felder, 1865
Wingspan of Adult Butterfly: 17 mm
Caterpillar Local Host Plants: Acacia auriculiformis (Leguminosae, common name: Earleaf Acacia, Black Wattle), Acacia mangium (Leguminosae, common name: Silver Wattle).


A Two-Spotted Line Blue checking out flowers of mile-a-minute in a hill park.


Another Two-Spotted Line Blue on a perch under the midday sun.

Physical Description of Adult Butterfly:

Upperside, the male is lilac with dark blue basal area while the female is dull brown with varying degree of blue in the basal area. Both sexes have two brown-black subtornal spots on the hindwing. Underside, both sexes are similarly marked. The forewing is pale orange-brown in base colour with a short band at cell-end, and a longer post-discal band, both of which are narrowly edged with brown and white. The hindwing is pale brown in base colour with a series of brown spots and bands narrowly edged with darker brown and white, and two black subtornal spots with a few iridescent green scales and ringed with pale yellow-brown.

A Two-Spotted Line Blue perching on flower buds of Acacia mangium.


A Two-Spotted Line Blue visiting flowers.

Field Observations of Butterfly Behaviour:

This species is Indo-Australian in origin, and was recently discovered in Singapore (see this BC blog article for details). Sightings of the tiny but usually restless adults have typically been in the vicinity of its local host plants, visiting flowers on nearby flowering shrubs or herbs. Both sexes have also been sighted, at times in large numbers, flying around or perched on inflorescence or foliage of the flowering host plants. In flight, they can easily be mistaken as other similarly-sized line blues. A definite identification can only be made when the butterfly comes to rest and allows its two trademark hindwing subtornal spots to be observed.

A Two-Spotted Line Blue perching on flower buds of Acacia auriculiformis.


A Two-Spotted Line Blue resting on a perch.

Early Stages:

In its homeland, Australia, Two-Spotted Line Blue (TSLB) is known to be utilizing a wide range of Wattles as larval food plant. In Singapore, an invasive and naturalized Wattle, Acacia auriculiformis (the Black Wattle), is thus far the only recorded host plant. The following account of the life history of this recent addition to our checklist is based on observations made of 20 plus specimens, in varying stages of development, taken from one local host plant in two visits within a week. Another local Acacia plant, A. mangium, is listed as a host plant for TSLB in Australian literature. Hence our bred caterpillars had no problem consuming its flower buds when introduced. Caterpillars of TSLB feed on both flower buds and blossoming flowers of the host plants.

Host plant: Acacia auriculiformis.


Host plant: Acacia mangium.

Eggs of Two-Spotted Line Blue are laid singly near a flower bud on an inflorescence of the host plant. Each egg is disc-like (about 0.4mm in diameter) with a depressed micropylar. The surface is covered with a reticulated pattern of intersecting ridges and pits of varying sizes. When freshly laid, the egg is pale green. The color turns to white as the egg matures.

A mating pair of the Two-Spotted Line Blue.


Two views of an egg of the Two-Spotted Line Blue. Diameter: 0.4mm.

Each egg takes 2-2.5 days to hatch. The young caterpillar emerges after nibbling away sufficiently large portion of the egg shell. Measured at a length of about 0.7mm to 0.8mm, its pale yellow body is cylindrical in shape, wider at the anterior, and sporting two rows of long dorsal setae, and moderately long sub-spiracular setae. The head capsule is dark brown or black in color.

Two views of a new hatched caterpillar, length: 0.7-0.8mm.

The newly hatched makes its way to a nearby flower bud and starts to munch on it. After about 2 days of growth, it reaches about 1.2mm in length and looks rather fattened. Its tiny size, matching coloration and its resting posture on the small flower buds makes it difficult for any casual observer to notice its presence.

A late 1st instar caterpillar on a flower bud, dormant prior to its moult to the next instar.
Length: about 1mm.

Still sporting the two rows of dorsal setae and sub-spiracular setae, the 2nd instar caterpillar now has numerous and very short setae covering its body surface. Its body colour is pale yellow with a green undertone. Dorsally, the body features a hump, wider at the anterior, and the two rows of dorsal setae essentially line the edges of the this hump. The head capsule is still dark brown to black in colour. The growth in this stage brings the caterpillar to a length of about 2.5mm, and after about 2 days in this stage, it moults again.

Two views of a 2nd instar caterpillar, length: 2mm.

The 3rd instar caterpillar does not have the two rows of long dorsal setae as in the previous two instars. The sub-spiracular setae are still present but rather short. The dorsal hump is now marked with paler patches along the two side edges, giving the impression of a green dorsal band on the ridge of the hump. Both the dorsal nectary organ and the tentacular organs are discernible in this instar. The 3rd instar takes 2.5-3 days to complete with the body length reaching about 4-4.5mm before the next moult. In the hours leading up to the moult, a number of brown markings, which will be featured strongly in the early part of the next instar, become visible on the body surface.

Two views of a 3rd instar caterpillar, length: 4mm.


3rd instar caterpillars. late in this stage, prior to moulting, length: 4mm.
Note the appearance of brown markings.

The 4th (and final) instar caterpillar has a number of brown markings on the whitish patches marking the two side edges of the dorsal hump, and more such brown markings in the sub-spiracular white patches. Brown lateral patches are found on the 1st abdominal segment. There is also a dorsal brown patch on 8th abdominal segment. The diamond-shaped prothoracic shield is white in color and embedded within a brown patch covering the entire dorsum of the prothorax. The head capsule is brown in colour. The nectary organs are rather prominent in this instar and the everted tentacular organs can be rather long (up to 1.5mm) and spectacular. See the attached youtube video (near the end of this article) of such a display.

Two views of a 4th instar caterpillar, length: 5.5mm.

As it eats and grows to a length of up to about 9.5mm (majority has a maximum length of about 8.5mm) within 3-4 days, the dorsal and sub-spiracular brown markings fade gradually, and the white dorsal and sub-spiracular patches becomes more intense in coloration and take on a pale yellowish tone.

Two views of a 4th instar caterpillar, late in this stage, length: 9.5mm.

On the last day of the 4th instar, the caterpillar ceases its feeding activity. Its body colour changes drastically to two extreme colour forms. In the red form, the body is mostly iridescent red while the green form mostly iridescent green. Some individuals take on an intermediate form between the red and green forms. Of the batch of 20-odd caterpillars bred, the red forms dominates and account for about 80% of all pre-pupae. At this point, the movement of the caterpillar is rather rapid as it wanders around in search of a pupation site.

Three different examples lf very late final instar caterpillars, showing colour variations.

In the breeding environment, the caterpillar typically chooses the tight space in a curled up leaf or the space between two leaves in a pile of leaf litter. At the chosen site, the caterpillar readies itself for pupation by spinning silk threads to secure itself and partially sealing off access point to the pupation site.

Two views of an immobile pre-pupa of the Two-Spotted Line Blue, Red form.


Two views of an immobile pre-pupa of the Two-Spotted Line Blue, Green form.

Pupation takes place after one day of the pre-pupal stage. The pupa has the typical lycaenid shape, pale brown in base colour with darker brown spots and blotches which are highly variable in numbers and sizes. Unlike most other lycaenid pupae, the pupa of Two-Spotted Line Blue does not secure itself with cremastral hooks to any silk pad, and its posterier end does not angle downwards. Length of pupae: 5-7mm.

Two views of a pupa of the Two-Spotted Line Blue, length: 6mm

Four days later, the pupa becomes darkened in color signaling the imminent emergence of the adult. The next day the adult butterfly emerges from the mature pupa.

Two views of a mature pupa of the Two-Spotted Line Blue.


A newly eclosed Two-Spotted Line Blue near its empty pupa case, waiting for its wings to be firmed up.

Life History of the Two-Spotted Line Blue.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
• Butterflies of Australia: Their Identification, Biology and Distribution, Volume Two, Michael F. Brady, CSIRO Publishing.

Text by Horace Tan, Photos by James Chia, Tan Ben Jin, Sunny Chir, Khew S K and Horace Tan

An Aussie Skipperoo Comes to Town

An Aussie Skipperoo Comes to Town
Introducing the Yellow Palm Dart (Cephrenes trichopepla)

It took quite some time of careful research and breeding the entire life history of this species before ButterflyCircle members finally confirmed that this Hesperiidae, which is usually found in Northern Australia, is now a permanent resident of Singapore (and also Malaysia!)

This skipper, which superficially resembles the local Telicota species, escaped notice for many years. It all started (now that I've had time to dig out my notes and emails from various people) with an email from a butterfly expert from Australia who was on holiday in Singapore. This was back in 1999! Kelvyn Dunn, who wrote me an email later in 2003, said this :

"Recently in Singapore (1999) I observed and examined in the hand (incl photographed) an example of Cephrenes trichopepla (an Australian sp.) in Fort Canning Park. I have video images.

Have you found any evidence of this skipper species as yet? I presume mine was not athe only one. (I can send pics if you want to see them to examine it for yourself).

In Australia my claim has met some scepticism because I did not preserve the adult."

At that point in time, ButterflyCircle hadn't even re-discovered the Plain Palm Dart (Cephrenes acalle niasicus) yet, so I was rather skeptical at Kelvyn's find too. The many lookalikes amongst the Telicota and larger Potanthus spp. didn't help either, so I assumed that Kelvyn's find was probably another one of the Telicota and left it at that.

Some time later, more individuals of this rather large skipper turned out in various locations in Singapore - public parks, gardens, flower nurseries and so on. By then, we had confirmation of the existence of the Plain Palm Dart after a few shots of the more distinctive females were validated. Hence I assumed that what Kelvyn observed in 1999 was probably a male Cephrenes acalle.

Although the males of the Plain Palm Dart had more angular apical forewing area, the markings on the undersides are less distinct than this other strange skipper that had clean orange colours and crisp markings on the undersides. The physical appearance of this butterfly didn't really match the markings of any of the Telicota spp shown in the reference books on Malaysian, Singaporean and even Thai butterflies.

So we continued with the belief that this skipper could be just be displaying variations of the markings of the extant species of Telicota or the solitary Cephrenes sp in Singapore.

More shots turned up of this species, which we incorrectly identified as one of the Telicota spp. But the larger size of many of the individuals sighted continued to intrigue me, although I put it down to variations in the sizes of the Hesperiidae, which occurs quite often amongst some other species. Even after managing to capture a mating pair of this species, I left it that it was one of the Telicota.

A mating pair of the Yellow Palm Dart observed near a reservoir park

By good fortune and chance, ButterflyCircle member Anthony Wong discovered a caterpillar feeding on coconut leaf (Cocos nucifera) during a survey of the offshore island of Pulau Semakau. Left in the good hands of our expert caterpillar farmer, Horace Tan, photos of the caterpillar indicated a physical difference from the Telicota caterpillars as shown in various reference books. This caterpillar had unique orange-yellow "cheeks" on both sides of its mandibles.

Close up of the Yellow Palm Dart's caterpillar, showing its orange-yellow "cheeks"

A quick research on Internet resources found a closely-matched early stages of the Australian skipper, Yellow Palm Dart (Cephrenes trichopepla). Shortly before this find on Pulau Semakau, our ButterflyCircle member in Kuala Lumpur, LC Goh, had also recorded complete life history of a an unidentified species of skipper in March 2009. Comparing the photos with more of the caterpillars that were eventually bred in Singapore, it was confirmed that what LC Goh bred, was also a Yellow Palm Dart!

Caterpillar of the Yellow Palm Dart, bred by LC Goh in Kuala Lumpur, Malaysia

Further consultations with Kelvyn Dunn, who generously provided photos and research papers that he had written on two resident Cephrenes in Australia, and also our Malaysian expert lepidopterist, Dr Laurence Kirton, it is now established beyond doubt, that the Hesperiidae species, the Yellow Palm Dart (Cephrenes trichopepla) is now part of the butterfly fauna in Malaysia and Singapore.

Male and Female Yellow Palm Darts - freshly eclosed specimens from caterpillars bred on Cocos nucifera

Both sexes of the Yellow Palm Dart are almost identical in appearance. The uppersides of the wings are dark brown to black, with orange bands on the forewings, and a wide discal band on the hindwings. The undersides are ochreous yellow with the markings distinctly marked in black. The hindwings beneath has a large black spot in the anal fold which separates it from all other species.

Males are exceedingly fast flyers but often stop to perch with its forewings held at an angle with the hindwings opened flat in the typical Hesperiidae fashion.

A male Yellow Palm Dart perches in the usual skipper fashion

The caterpillar host plant on which the species was bred in Singapore is the Coconut Palm. However, the species is known to also feed on various other Palmae in Australia.

So, as we wish "G'day, mate" to this Australian "foreign talent" and new addition to the Singapore (and Malaysian) checklists - the Yellow Palm Dart, we also hope to one day see another similar Australian species the Orange Palm Dart (Cephrenes augiades) reaching the shores of Singapore.

Specimens shots of the Yellow Palm Dart, courtesy of the James Cook University, Australia

In conclusion, Kelvyn, if you are reading this article, you can now assure your skeptics that you indeed saw a Yellow Palm Dart here in Singapore in 1999. Your valued discussions over emails and articles and photos that you sent me are very much appreciated.

Text by Khew SK ; Photos by Sunny Chir, LC Goh, Khew SK & Horace Tan

Further Reading :

• South Australian Butterflies Data Sheet by R. Grund 2004

Butterfly of the Month - January 2010

Butterfly of the Month - January 2010
The Common Birdwing (Troides helena cerberus)

We start a fresh decade in the 21st Century with one of the largest butterflies in Singapore, the Common Birdwing. This species is not rare, and where the host plant is plentiful, there have been occasions where a number of individuals have been seen, as were their caterpillars, in locations like the Singapore Botanic Gardens, Singapore Zoological Gardens and Alexandra Hospital Butterfly Trail.

It is always an uplifting experience to see a Birdwing in flight - with its contrasty black-and-yellow colour scheme, the butterfly is conspicuous, large and showy. As it flutters and glides high at the treetops, the flight of the Birdwing is reminiscent of that of birds. The species descends to flowering plants like the Pagoda Flower, Hibiscus, and even Lantana, to feed. Typical of the flight of Papilionidae, the Common Birdwing's forewings flutter rapidly, whilst the hindwings are kept almost still, when it is feeding at flowers.

The Common Birdwing has black forewings with the veins beyond the cell edged with pale greyish streaks that are more conspicuous in the female. Some individuals however, may lack these pale streaks altogether. The hindwing is a rich golden yellow edged with black, and the female has a complete series of large black submarginal spots that are usually not conjoined. Males may have one or more spots, but never a complete series

Unlike the typical males of the Papilionidae, the male Common Birdwing is rarely observed puddling at muddy footpaths and stream banks. Both sexes can often be found flying in the vicinity of their host plant, Aristolochia acuminata.

Whilst the species cannot be considered rare, it is a species that is vulnerable to extinction if its host plant disappears from Singapore's parks and forests. This species shares the host plant with another Papilionidae, the Common Rose (Pachliopta aristolochiae asteris).

The Common Birdwing has the distinction of being the only species in the Singapore Checklist to be listed in the Convention on International Trade in Endangered Species (or CITES) Appendix II. Appendix II lists species that are not necessarily now threatened with extinction but that may become so unless trade is closely controlled.

The conservation strategy to enhance the chances of survival of this spectacular species would be to continue to cultivate its host plant in more locations especially in parks, park connectors and even private homes in Singapore.

Text by Khew SK : Photos by Bobby Mun, Khew SK, Terry Ong, Benedict Tay & Anthony Wong

Life History of the Plain Palm Dart

Life History of the Plain Palm Dart (Cephrenes acalle niasicus)



Butterfly Biodata:
Genus: Cephrenes Waterhouse & Lyell, 1914.
Species: acalle Hopffer, 1874
Sub-species: niasicus Plotz, 1886
Wingspan of Adult Butterfly: 45mm
Caterpillar Host Plants: Livistona sp. (Arecaceae), Cocos nucifera (Arecaceae; common name: coconut)


A male Plain Palm Dart visiting flowers of Syzygium species in a hill park.


A female Plain Palm Dart visiting flowers of Syzygium species in a hill park.

Physical Description of Adult Butterfly:

The adults, especially the males, are similar to Telicota spp. but are generally larger. However, unlike the Telicota spp, the male lacks a stigma (a secondary sexual character). Above, the male is dark brown with orange-yellow markings, which includes on the forewing, a post-discal band running from dorsum to vein 6 and three subapical spots, and on the hindwing, an orange-yellow discal band, central streaks and tornal cilia. The female's markings are usually very sullied. and the hindwing beneath has an oily sheen and may be coloured green, bluish and purple. Beneath, the male is ochreous with markings outlined in black spots. The female has an oily sheen, especially on the forewing apex and hindwing, and may be coloured green, bluish and purplish. In the females, the markings on the hindwing are generally defined by dark spots, but these could be absent in some specimens, making the markings obscure.

A newly eclosed male Plain Palm Dart flexing its proboscis.


Another male Plain Palm Dart visiting flowers of Syzygium species in a hill park.

Field Observations of Butterfly Behaviour:
The adults are rarely encountered in Singapore, due likely to their habit of being more active at dawn and dusk. So far, sightings of the swift flying adults have been restricted to parts of Southern Ridges and in Pulau Ubin, and typically on flowering plants such as the Syzygium species.

Early Stages:


Host plant: Livistona sp.

The eggs are laid singly on the underside of a host plant leaf. Each dome-shaped egg is creamy yellow with a flat base. The micropylar sits atop. Upon close inspection, numerous tiny and inconspicuous pits can be seen on the egg surface. The eggs are rather large with a diameter of about 1.7-1.8mm.

Two views of an egg of the Plain Palm Dart, diameter: 1.75mm.

It takes 5-6 days for the collected egg to hatch. The egg first develops red patches on the pole and in an equatorial belt, and then turns dark pinkish-red with the dark head capsule becoming visible through the egg shell. The reddish coloration fades away in the day prior to the hatching event.

Maturing egg with a red polar patch and a red equatorial belt.


Mature egg with a faint view of the head, with the one in the right panel closer to hatching.

The young caterpillar eats just enough of the shell to emerge, and then immediately proceeds to finish the remaining egg shell. The newly hatched has a length of 5-5.5mm. Its creamy white body is cylindrical in shape with dorsal, lateral and sub-spiracular setae, all of which are short with the exception of those at the posterior end. The large head is black with a few short white setae. A black collar, as in common in many 1st instar skipper caterpillars, is found on the prothorax just behind the head. All instars of the the Plain Palm Dart feed on the mature leaves of the host plant, and constructs leaf shelters by joining folds of a leaf together.

Top: Newly hatched 1st instar caterpillar, length: 5.5mm.
Bottom: A few hours old with a greenish undertone (after some bites of the host plant leaves).

The body soon takes on a green undertone after a few feeding sessions on the leaf. Its movement on leaf was observed to be rather quick-paced. The 1st instar takes a total of 4-5 days to complete with body length reaching 7.5-11mm.

Two views of a 1st instar caterpillar, late in this stage, length: 7.5mm.
With leaf shelter almost closed (top); and opened up (bottom).

The body of the 2nd instar caterpillar resembles that of the first instar, but with the dark collar on the prothorax absent. The tuff of long setae at the posterior end is still prominent lyfeatured. This instar lasts a total of 3-5 days with the body length reaching up to 14mm.

Two views of a 2nd instar caterpillar, newly moulted, length: 7mm.


Two views of a 2nd instar caterpillar, late in this stage, length: 14mm.

The yellowish green 3nd instar caterpillar resembles the 2nd instar caterpillar except for variations in coloration and markings on the head capsule. While some specimens still sport a black head capsule, others have light brown to beige head capsule margined in dark brown with varying extent of light brown/beige as the base colour. This instar lasts a total of 4-6 days with the body length reaching up to 19-21mm.

3rd instar caterpillars, early in this stage.
Lengths: 13.5mm (top,female); 14mm (bottom, male).


3nd instar caterpillar, late in this stage, length: 20mm.

The 4th instar caterpillar is now consistent in having a light brown to beige head capsule margined in dark to reddish brown. This instar lasts 6-7 days with the body length reaching up to 27-31mm.

4th instar caterpillar, early in this stage. Lengths: 17mm (top), 19mm (bottom).


Two views of a 4th instar caterpillar, late in this stage, length: 29mm.

A dark green dorsal line, faint in the late 4th instar caterpillar, becomes prominent in the 5th instar.


Two views of a female 5th instar caterpillar, early in this stage. Length: 32mm.


Two views of a male 5th instar caterpillar, early in this stage. Length: 32mm.

The 5th instar takes about 7-8 days to complete with the body length reaching up to 43mm, In the last day of this instar, the caterpillar ceases feeding and its body colour turns milky green with a strong pinky undertone.

Two views of 5th instar caterpillar, late in this stage. Top: male (42mm), female (43mm).


Two views of a 5th instar caterpillar, with body color changes prior to becoming a pre-pupa.

Towards the end of 5th instar, the body of the caterpillar shortens appreciably. Soon the caterpillar becomes dormant in a leaf shelter which it seals with a copious amount of silk threads. In the tightly closed pupation shelter, the caterpillar also secretes large quantity of whitish waxy substance. This prepupatory phase lasts for 1-2 days.

Two views of a pre-pupa of The Plain Palm Dart.

Pupation takes place within the leaf shelter. The pupa does not have a cremaster nor a silk girdle and it is mainly secured with tightly woven silk threads in the shelter. It has a short thorax, a rather long abdomen, a short and pointed rostrum. The body is pale green in the thorax and wing pad areas, but pale yellowish brown in the abdomen. Length of pupae: 21-26mm.

Two views of a pupa of the Plain Palm Dart, length:24mm

After 8-9days, the pupa becomes mostly brown with the wing pad areas showing the orangy markings on the forewing upperside. Eclosion takes place the next day.

Three views of a mature pupa of the Plain Palm Dart.


A newly eclosed female Plain Palm Dart.


A newly eclosed male Plain Palm 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 by Horace Tan, Photos by Khew SK and Horace Tan

Butterfly Survival Strategies - Part 2

Butterfly Survival Strategies - Part 2
Cryptic colouration, masquerade, startle, dazzle and decoy

A Dark Blue Jungle Glory perches on a leaf. Its cryptic undersides will render the butterfly well camouflaged when it forages amongst dead leaf litter on the forest floor.

In the first part of this series, we saw how some butterfly species have evolved to mimic their unpalatable cousins for protection against predators. This phenomenon of protective colouration gives the mimic a better chance of survival in the field, and in particular, females of the species, a higher odds of survival long enough to lay her eggs for the next generation.

A typical forest floor covered with dead leaf litter and twigs. Can you spot the two butterflies feeding on rotting matter on the forest floor?

In this part, we look firstly at adaptive colouration of butterflies based on the need of concealment or crypsis (defined simply as a strategy to reduce the probability of detection). This principle of concealment throught colouration was discussed by AR Wallace as the "visual similarity between animal and its background". This theory has been explained by many examples in the animal world - from the white polar bears that live in essentially white snow-covered habitats, to the colour differences in marine animals like sharks where its dorsal and ventral colour differences help in concealment of its presence in its environment, depending on whether viewed from above or below.

Camouflage

Saturns feeding on rotting fruit. How many can you see in the picture?

There are many examples in butterfly evolution, where cryptic colouration has been employed to render the butterfly 'invisible' to predators. This is done via disruptive patterning and colours to resemble its surroundings. The objective here of course, is the theory supporting the notion that predators 'cannot attack what the cannot see'.

Another Dark Blue Jungle Glory well camouflaged amongst dead leaf litter on the forest floor

Cryptic colouration, coupled with the behaviour of the various butterfly species in their preferred habitats is one of their survival strategies to avoid being predated upon for as long as possible.

Five large Morphinae with cryptic colouration on the undersides of the wings. With eyespots, lines that break the silhouette and colours that blend in with the forest floor habitats that they frequent, their camouflage help them stay 'invisible' from predators as they feed. Clockwise from top left - Koh-I-Noor (Amathuxidia amathaon), Tufted Jungle King (Thauria aliris), Giant Saturn (Zeuxidia aurelius), Dark Jungle Glory (Thaumantis noureddin) and Palm King (Amathusia phidippus)

Flash and Dazzle

In what is described as "startling patterns", prominent eyespots in butterflies have been shown to divert the attention of inexperienced avian predators. In his experiments with the Peacock Butterfly (Inachis io), David Blest (1957) found that this 'startle display' made young birds back off, even if for a moment, giving the butterfly that fleeting moment to escape. Locally, related species like the Junonia probably have the same effect on predators.

Large eyespots on the wings of the butterflies that may startle would-be attackers into hesitating for a fleeting moment will allow the butterfly to escape with its life

Another example of this strategy is the Great Helen (Papilio iswara iswara). At rest with its wings opened flat, the butterfly's forewings conceal the white patch on the hindwings, making it appear totally black. But when started, it flashes the white patch to 'dazzle' a would-be predator momentarily, giving it a precious moment to make good its escape.

The Great Helen is a good example of a species that employs "dazzle" to startle its would-be attacker. When at rest, the large white patches of the wings are hidden. When alarmed, it takes off, flashing the white patches that may catch the attacker off-guard whilst it is startled for a moment

Many species of butterflies also display an array of eyespots - some on the uppersides and some on the undersides of the wings. Eyes or the display of eyes, tend to make a predator wonder if there are indeed any other animal lying in wait for it. A momentary hesitance makes a difference in whether the butterfly escapes or ends up as lunch.

Eyespots on the outer fringe of the wings of some Satyrinae may cause some inexperienced predators to hesitate as they check out the eyes.

In some species like the Mycalesis, the spots are always ranged along the outer margins of the wings, never close to the body. Even if a predator decides to attack the 'eyes', it will take out a part of the butterfly's wing that may not be critical, allowing the butterfly to escape with its life, albeit without a small piece of its wings.

Masquerade

The Leaf Butterfly is a pretty iridescent blue above with orange bands, but when alarmed it settles with its wings closed to resemble a dead leaf.

As an alternative to purely employing cryptic patterns to camouflage itself, some butterfly species employ the strategy of masquerading as a non-palatable part of its environment, or at least 'pretend' to be something else to conceal itself. The famous Leaf Butterfly (Kallima limborgii) in Malaysia and (Kallima inachus) in Thailand and northwards, and (Kallima paralekta) in Java and southwards, demonstrates this method of concealment.

Another shot of the Leaf Butterfly masquerading as a dead leaf whilst it feeds

On the upperside, the butterfly is a rich purple blue, with a broad orange subapical band on the forewing. The underside very closely resembles a dead leaf, complete with a midrib, petiole and even patches of fungal growth on the leaf!

The undersides of the Autumn Leaf and Saturn also resemble dead leaves. Note the colourful orange upperside of the Autumn Leaf when it spreads its wings to sunbathe.

In Singapore, several other species like the Autumn Leaf (Doleschallia bisaltide) and to a certain extent, the Saturn (Zeuxidia amethystus) are less successful examples of trying to masquerade as dead leaves.

Decoy

Many Lycaenids display "false heads" complete with eyes and antennae to fool predators into attacking the "wrong" side of the butterfly

Many Lycaenidae are excellent examples of employing the strategy of creating 'decoys' whereby a predator is fooled into attacking the less vital parts of the butterfly. These species have evolved to create a 'false head' whereby the tornal area of the hindwing featuring a prominent 'eye' with one or more pairs of tails making them appear like antennae. Indeed, in the field, many of these species also accentuate this part their hindwings by moving them up and down when at rest, causing the 'false head' to be more active and calling attention to the 'wrong side' of the butterfly to a would-be predator.

Underside of the Common Red Flash featuring false eyes and antennae. Below is a shot depicting a possible survivor of an avian attack with the hindwings showing bite marks in a previous encounter.

The filamentous white-tipped tails of many species are also very 'lively' when wafted in a breeze, as are the long and white tails of many of the long-tailed Lycaenids. Coupled with the patterns, colours and tails, these butterfly species create a 'decoy' false head so that a predator attacks a less vital part of the butterfly, giving it a chance to survive and escape, but without a piece of its hindwings.

An Ambon Onyx showing off its "false head"

So now we see, despite being virtually harmless and unable to defend themselves with any aggressive 'weaponry', natural selection has allowed butterflies to adapt and evolve other strategies to even the odds of survival in the field via the colours and shapes of their wings, and their behaviour in their preferred habitats.

Text by Khew SK : Photos by Goh LC, Khew SK, Tan CP & Yong San

Life History of the Colour Sergeant

Life History of the Colour Sergeant (Athyma nefte subrata)

Butterfly Biodata:
Genus: Athyma Westwood, 1850
Species: nefte Cramer, 1779
Subspecies: subrata Moore, 1858
Wingspan of Adult Butterfly: 60mm
Caterpillar Host Plants: Glochidion brunneum (Euphorbiaceae), G. superbum (Euphorbiaceae) and one un-identified plant in the nature reserve.


The upper- and underside of a female -f neftina Colour Sergeant.


The upper- and underside of a female -f subrata Colour Sergeant.


The upper- and underside of a male Colour Sergeant.

Physical Description of Adult Butterfly:
The adult has a closed cell in the forewing. The upperside of the forewing has contiguous/conjoined white cell post-discal spots from the dorsum to spaces 2 and 3. and confluent post-discal spots in spaces 4, 5 and 6 with their inner edge in line. The sexes are dissimilar. The male is a rich velvety black, with white markings tinged with bluish. The male in Singapore typically has an orange sub-apical spot in space 6 on the forewing upperside. This spot is usually white for males found in the Malay Peninsula. The female occurs in two distinct forms. In the -form neftina (Fruhstorfer) the wings are marked with broad orange-brown stripes arranged in the usual manner. The -form subrata (Moore) is a dark dull chocolate brown, with narrow and rather diffuse tawny brown markings. Both female forms are less abundant than the male, with -f neftina appears to be more common among the two female forms.


A female -f neftina Colour Sergeant.


A female -f subrata Colour Sergeant perching on a leaf in a western wasteland.

Field Observations of Butterfly Behaviour:
This species is relatively common in Singapore. Sightings of the fast flying adults are rather frequent and widely distributed, both in nature reserves and urban parks. In sunny weather, both sexes can be found flying in the vicinity of flowering shrubs and taking nectar.


A female -f neftina Colour Sergeant visiting a ripened fruit of the Singapore Rhododendron.


Another female -f neftina Colour Sergeant perching on a leaf of the Singapore Rhododendron.

Early Stages:


Host plant: Glochidion brunneum.


Host plant: Glochidion superbum.


Host plan: an unidentified plant in the nature reserve with leaves playing host to a number of Colour Sergeant caterpillars.

Thus far, two species of Glochidion and one un-identified plant (likely to be a Glochidion sp. too) have been identified as the local host plants. Caterpillars of the Colour Sergeant adopt the same feeding and frass-management routines as described for the Commander and other Athyma species in earlier blog articles.

Two views of an egg of the Colour Sergeant.

The eggs of the Colour Sergeant are laid singly at the tip of a leaf on the host plant. The dark yellowish eggs are somewhat globular in shape, with its surface marked with hexagonal pits and bearing short spines at pit corners, giving them the appearance of minute sea-urchins. Each egg has a diameter of about 1mm.

Two views of a mature egg of the Colour Sergeant. The head and mandibles are visible in the right view.

The egg takes about 2-3 days to hatch. The young caterpillar emerges by eating away part of the egg shell. The rest of the egg shell becomes the first meal for the newly hatched, which has a cylindrical pale yellowish green body covered with many small tubercles and short setae. The head capsule is pale to dark brown in color.


A newly hatched caterpillar of the Colour Sergeant, length: 1.8mm.

Similar to the feeding habit of the other Athyma spp., the 1st instar caterpillar of the Colour Sergeant also feeds from the leaf tip and leaves the midrib intact and protruding. A frass chain is also constructed laboriously by the young caterpillar at the tip of the exposed midrib. Between feeds, the caterpillar rests on either the exposed midrib or the frass chain. In later instars, the caterpillar tends to rest near where the protruding midrib joins the remaining lamina. At this site, it also attempts to camouflage itself with a collection of frass pellets secured with silk threads to the lamina.


Two views of a 1st instar caterpillar of the Colour Sergeant. Length: 5mm.


One 1st instar caterpillar resting on the exposed midrib/frass-chain structure.

After reaching about 4.5-5.0mm in about 3 days, the caterpillar moults to the 2nd instar. The body color of the 2nd instar caterpillar is dark brown with a green undertone. There are a number of small and dark dorsal and lateral patches. Besides tiny tubercles covering most of its body surface, the 2nd instar caterpillar also features short and branched spines dorso-laterally and spiracularly. The head capsule is dark brown and dotted with a number of conical tubercles. This instar lasts about 2-3 days with the body length reaching 6.5-7.0mm.


Two views of a newly moulted 2nd instar caterpillar, length: 4.8mm


2nd instar caterpillar, late in this stage, length: 6.8mm

The 3rd instar caterpillar has slightly longer dorsolateral spines, with pairs on thoracic segments longer than the rest. Its head capsule is dark brown to black irorated with pale brown tubercles. Broad pale brown markings on abdominal segments 3 and 5 with a diamond-shape outline become increasing prominent during this stage. This instar takes about 3 days to complete with body length reaching about 10-11mm.


Two views of a 3rd instar caterpillar, length: 8.5mm


Two views of 3rd instar caterpillar, late in this stage. .Length: 11mm.

The 4th instar caterpillar has much longer dorso-lateral spines which are heavily branched. The body is brown to black in color. Besides conical tubercles, the head capsule also carries some short spines. Broad pale green markings appear on the dorsum of the 1st and 3rd abdominal segments. Also, pale brown to pinkish brown marking appears on the 5th abdominal segment. This instar lasts 3-4 days with body length reaching about 18mm-19mm.


Two views of a newly moulted 4th instar caterpillar, length: 11mm.


Two views of 4th instar caterpillar, late in this stage. Lengths: 14.5mm.

In the 5th (final) instar, the branched dorso-lateral spines very well developed on all body segments with those on the meso- and metathorax being the longest. Newly moulted caterpillar has yellowish brown body colour with broad dorsal markings on the 1st and 3rd abdominal segments and a broad black dorsal marking on the 5th abdominal segment. The body base color soon changes to a uniform green color as growth proceeds in this instar, leaving only the saddle marking on the 5th abdominal segment in contrasting reddish/pinkish brown. The dark brown head capsule has much longer and pointed spines.


Two views of 5th instar caterpillar, early in this stage. Lengths: 20.5mm.


Two views of a 5th instar caterpillar, later in this stage, length: 30mm.

As with other members of the Limenities subgroup, when disturbed, the caterpillar adopts a characteristic posture with the anterior body arched and the head tucked beneath the thorax.


Two views of a 5th instar caterpillar adopting an on-guard stance.

The 5th instar lasts for 4-5 days, and the body length reaches up to 35mm. On the last day, the base body colour changes to yellowish green and then to yellow. Rather large dark markings, roughly circle in shape, also appear laterally.


Two views of a 5th instar caterpillar, late in this stage, length: 35mm.

Additional dark patches have appeared dorsally and laterally.

Two views of a 5th instar caterpillar, late in this stage, with base color changed to yellow.

Soon, the caterpillar ceases feeding and wanders around. Eventually it chooses a spot on the underside of branch/stem/leaf and spins a silk pad from which it hangs vertically to take on the pre-pupatory pose.

Pre-pupatory larva of the Colour Sergeant.

Pupation takes place a day later. The pupa suspends itself from the silk pad with no supporting silk girdle. It is almost entirely pale brown in color with segments and parts outlined in a darker shade of brown. A few gold patches also adorn the pupal surface. The abdominal segments are slender, and the thoracic portion being larger and expanded laterally. Dorsally, there are two prominent processes curved towards each other. When disturbed, the abdominal segments flex laterally, and could stay in that position for a period of time. Length of pupae: 23-25mm.

The pupation event of a Colour Sergeant caterpillar.

Three views of a pupa of the Colour Sergeant.


A pupa of the Colour Sergeant sighted on the underside of a leaf in the nature reserve.

After about 5-6 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The spots and streak on the forewing upperside also become discernible. The next day, the adult butterfly emerges from the pupal case, typically during the morning hours.

Three views of a mature pupa of the Colour Sergeant.

The eclosion event of a male Colour Sergeant at 2x speed.

A newly eclosed Colour Sergeant resting on its pupal case.

References:

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

Text by Horace Tan, Photos by Sunny Chir, Federick Ho, L C Goh and Horace Tan.