Tigers and the Belimbing Sg Buloh Wetland Reserve on a hot sunny Tuesday
It was a hot and windy day, and the searing heat seemed to chase even the most robust of butterflies into hiding. However, at a remote corner of the wetland reserve, was a clump of trees that provided much-needed sustenance to more than a dozen Blue and Dark Glassy Tigers.
The typical long bi-pinnate leaf arrangement of the Belimbing tree
The trees were flowering from the trunks, as is the normal case for this species of Camias (Averrhoa bilimbi) or the Belimbing as the locals call it. The Belimbing fruit is well-known for its sour and adicic taste. The species is a close relative of the Starfruit (Averrhoa carambola) another well loved fruit in South East Asia.
The attractive flowers of the Belimbing
The tree is native to Malaysia and Indonesia. The Belimbing is well known for its green 'papaya-shaped' fruits that grow to about 10cm long. Most of the time, the Belimbing is dropped into dishes that call for a tangy or sour taste, such as sambals, pickles and chutnies, and is a regular addition to Peranakan cuisine and many local Malaysian dishes. The juice of the fruit has many medicinal uses as well.
The fruits of the Belimbing hang straight off the branches and trunk of the tree
The Belimbing trees at SBWR have always been at this location, but this is probably the first time that I've encountered them flowering and fruiting in profusion. Lucky for the butterflies too, as the Blue and Dark Glassy Tigers seemed to be in season this period, and I stopped counting them during the walk after reaching a total of 30.
The red-purple flowers of the Belimbing are pretty and attractive in their own right. Unlike their sour fruits, I'm quite sure the nectar is sweet, as the butterflies were scrambling over each other, going for the fresher flowers on the tree.
Besides the dominance of the Glassy Tigers, other species that were also spotted around the tree that also stopped for a taste of the nectar were the Common Grass Yellow, a King Crow and an unidentified Arhopala which scooted off quickly as I approached it.
A Common Grass Yellow and Dark Glassy Tiger joining in the nectar feast at the Belimbing tree
The structure of the flower is such that the stamens and pistil extend outwards and I observed that as the butterflies' proboscis reached deep into the flower for nectar, the body and legs of the butterflies were doing their work in pollinating the flower.
Pollinating the flower whilst feeding on nectar
From the photography viewpoint, shooting the rather drab-coloured 'tigers' complemented with the strongly coloured flowers of the Belimbing added a nicer dimension to the otherwise boring butterfly in terms of colour balance and composition.
Text and Photos by Khew SK
Further Reading :
Camias (Belimbing) by Thulaja, Naidu Ratnala, National Library Board, Singapore
A male Archduke perching on a leaf on the side of a forest trail.
A male Archduke displaying its wing upperside.
Physical Description of Adult Butterfly:
Above, the male is dark velvety black above with a broad greenish-blue distal border on the hindwing, which is continued narrowly along the termen of the forewing. The larger female is dark brown, and profusely spotted with yellow. Underneath, the male is deep ochreous brown with yellow spots. The female is dark brown on the forewing and pale grayish green on the hindwing; with both wings spotted with white. The apical portion of the antennal club is orange in both sexes.
A female Archduke found feeding among leaf litter in the nature reserve.
Another female Archduke resting on a dry leaf in the nature reserve Field Observations of Butterfly Behaviour:
The Archduke is relatively common in the nature reserves. Adults are typically sighted on shaded trails and among undergrowth, and are seldom seen in open sunny areas. It is mainly a forest dweller and adults are often seen puddling on damp ground, or feeding on rotting fruits and other organic matter amongst forest litter. Refer to this earlier ButterflyCircle's blog article for a more detailed write-up on this species.
Early Stages:
The host plant, Cratoxylum cochinchinense, can be found growing naturally in the nature reserves and planted as wayside trees in various urban parks. It has simple and opposite leaves which are red to dark red when young. Its red bark can peel off in strips or angular pieces. The bisexual flowers are pinkish to darker red. Besides Archduke, this plant is also utilized by Short Banded Sailor and Common Grass Yellow as larval food plant. Caterpillars of Archduke feed on older and more mature leaves of this plant.
Host plant : Cratoxylum cochinchinenseLeaves (left) and flowers (right).
A mating pair of the Archduke on forest ground.
The eggs are laid singly on the underside of a leaf of the host plant. Each egg is dome-shaped with a base diameter of about 1.8mm. The surface is covered with large irregular hexagonal depressions with hair-like protuberances emerging from adjoining corners. The tip of each "hair" carries a tiny fluid droplet. The color is initially dark green but turns purplish brown on day 2.
Two views of an egg of the Archduke on day 1.
Two views of an egg of the Archduke, one day prior to hatching.
After about 4 days, the 1st instar caterpillar emerges and proceeds to eat the eggshell as its first meal. The caterpillar is yellowish orange in body colour and has a head capsule in darker shade of yellowish-orange. Its body sports ten pairs of short dorso-lateral protuberances complete with long black setae. Frass pellets are usually seen attached to the tip of these setae in this instar. The caterpillar grows from an initial length of about 2.5mm to 7mm in three days. The subsequent moult takes it to the 2nd instar.
Newly hatched 1st instar caterpillar eating its own egg shell, length: 2.5mm. 1st instar caterpillar, length: 6mm
The moulting event of an Archduke caterpillar from 1st to 2nd instar at 6x speed.
The body of the 2nd instar caterpillar is predominantly orangy brown. All ten pairs of short protuberances seen in the 1st instar have lengthened considerably. Each is projected horizontally with numerous branched spines and is almost always pressed to the leaf surface. Each protuberance is mainly pale yellowish in color with some spines colored black in the middle and the tip portion. The 2nd instar lasts for three days with the body length reaching about 11mm before the moult to the 3rd instar. When alarmed, the caterpillar (both in this and later instars) typically reacts by curling up its body, and hiding its head under the "umbrella" of spines so creaed. (Note: all body lengths given in this article do not factor in lengths of the protuberances, and will simply give the length from the head capsule to the last body segment.)
Two views of 2nd instar caterpillar, length: 8mm
A 2nd instar caterpillar of the Archduke, length: 8mm
A 2nd instar caterpillar adopting a defensive stance, length: 8mm
The 3rd instar caterpillar is still orangy brown in body color. The protuberances have all become much longer in proportion. The branched spines appear almost like a bird's feather, with the secondary spines arranged neatly around the main spine. The tip section of the main spine is colored in brighter shade of yellow compared to the rest of the protuberance. Dorsally there are two long and thin bands, in much lighter shade of orangy brown. The 3rd instar lasts for 4-5 days and reaches a length of about 16-18mm before the next moult. Towards the end of this instar, the body color gradually changes to pale yellowish green.
3rd instar caterpillar adopting an defensive stance, early in this stage.
3rd instar caterpillar, length: 14mm
3rd instar caterpillar, late in this stage, length: 16mm
The 4th instar caterpillar has similar appearance as in the 3rd instar but with a pale yellowish green body color. Branched spines on each long protuberance are mostly pale green with just a few black in color scattered along its main axis. The few spines at the tip portion are all black. The distal portion of the protuberance is colored yellowish orange. As the caterpillar grows in this stage, the portion lying below this orange end will assume a strong bluish tone. On the body, the two dorsal lines are now more prominently marked, and are more constricted where adjacent body segments join. After 6-7 days in this instar, with its length reaching 28-30mm, the caterpillar moults to the 5th and final instar.
A 4th instar caterpillar which has just shed its old skin. length: 16mm
Three views of a 4th instar caterpillar, early in this instar, length: 16mm
4th instar caterpillar, length: 28mm
The moult from 4th to 5th instar of an Archduke caterpillar at 6x speed. Part 1/2: shedding the old skin.
The moult from 4th to 5th instar of an Archduke caterpillar at 6x speed. Part 2/2: inflating the new set of spines.
Essentially similar to the 4th instar caterpillar, the 5th instar features a brighter shade of green, especially so on the basal halves of the protuberances. It has also acquired a ferocious appetite, finishing one or two large leaves in a day.
5th instar caterpillar, newly moulted.
5th instar caterpillar, late in this stage, length: 49mm.
This final instar lasts for 8-9 days with the caterpillar reaching a mature length of about 50mm. On the last day, its body becomes shortened but hardly decolorized. It then seeks out a spot on the midrib on the underside of a mature leaf and stays put. There it laboriously spins large quantity of silk threads to make a silk mound, to which its posterior claspers are then attached to, typically with pre-pupa in an upside down posture. The dorsal lines disappear at this juncture and a whitish saddle mark can be seen on the 2nd abdominal segment.
Two views of a pre-pupa of the Archduke.
After 1 day of the pre-pupal stage, pupation takes place with the pupa suspended with its cremaster firmly attached to the silk mound on the midrib. The pupa is smooth and tapers steeply towards each end from a high transverse dorsal ridge which is lined with brown and a broader beige-colored transverse band. The light green pupa has a series of beige-colored spots symmetrically arranged. Two short cephalic horns, beige-colored with a brown patch, are also featured. Length of pupae: 26-28mm.
The pupation event of an Archduke caterpillar at 8x speed.
Two views of a pupa of the Archduke.
Ten days later, the pupa becomes considerably darkened, signaling the end of the development of the adult still encased within. The next day, the adult butterfly ecloses and stays near the empty pupal case for an hour or two before taking off to continue its life circle.
Two views of a mature pupa of the Archduke.
A newly eclosed male Archduke resting near its empty pupal case.
References:
The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006
Text by Horace Tan, Photos by Henry Koh, Mark Wong, Khew SK and Horace Tan
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 Crotalariaspp.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
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