Life History of the Archduke

Life History of the Archduke (Lexias pardalis dirteana)

Butterfly Biodata:
Genus: Lexias Boisduval, 1832
Species: pardalis Moore, 1878
Subspecies: dirteana Corbet, 1941
Wingspan of Adult Butterfly: 90mm
Caterpillar Host Plants: Cratoxylum cochinchinense (Hypericaceae, common name: Yellow Cow Wood), Cratoxylum pruriflorum (Hypericaceae).


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 cochinchinense Leaves (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

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 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