29 November 2008

Life History of the Dot-Dash Sergeant

Life History of the Dot-Dash Sergeant (Athyma kanwa kanwa)

Butterfly Biodata:
Genus: Athyma Westwood, 1850
Species: kanwa Moore, 1858
Subspecies: kanwa, Fruhstorfer, 1906
Wingspan of Adult Butterfly: 60mm
Caterpillar Host Plants: Uncaria spp. (Rubiaceae)

A Dot-Dash Sergeant resting on a perch in the nature reserve, showing us its undersides

A Dot-Dash Sergeant resting on a leaf in the nature reserve

A Dot-Dash Sergeant puddling on a trail in the nature reserve

Physical Description of Adult Butterfly:
Above, the Dot-Dash Sergeant is dark brown to black with an interrupted, white, macular and curved fascia running from mid-costa on the forewing to near the base of the dorsum on the hindwing. On the forewing, the white post-discal spot in space 2 is roughly oval and well separated from the spot in space 1b. Usually there is no post-discal spot in space 3. The forewing cell-streak is entire and separated from the triangular spot beyond. There are submarginal lines of white markings irrorated with dark scales on both wings, that on the hindwing taking the form of a broad band running from the apex to dorsum. The underside is greyish brown with markings as on the upperside.

Field Observations of Butterfly Behaviour:
Locally the Dot-Dash Sergeant is uncommon. Sightings of adults have been confined to a few locations in the northern and western part of the Central Catchment Nature Reserves where its host plants, Uncaria spp. are growing. The adults fly with a strong swift flight. Individuals have been seen around flowering trees and puddling on trails within the nature reserves.

Early Stages:
Four species of Uncaria (see attached picture) growing in the nature reserves have been found to be host plants for Dot-Dash Sergeant. Species #3 is suspected to be U. lanosa. Species #4 was previously recorded as the host plant for Lance Sergeant and Commander. Dot-Dash Sergeant shares the same feeding routine and utilization of frass chain/bundles as described therein for these two species.

Local host plants: 4 Uncaria spp. found in the nature reserves.

A female Dot-Dash Sergeant ovipositing on a leaf tip of Uncaria #1

The eggs of the Dot-Dash Sergeant are laid singly at the tip of a leaf on the host plant. In a behavior typical of members of its genus (and some other genera), the mother butterfly first lands on the surface of the leaf, and with its head pointing towards the petiole, it reverses until its abdomen tip reaches the drip tip of the leaf, and there it lays an ovum. The eggs are somewhat globular in shape, with 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.

A freshly laid egg of Dot-Dash Sergeant at the leaf tip of Uncaria #1. Diameter: 1mm.
In this case, the mother butterfly laid it next to a failed egg.

A mature egg with few hours to hatching

The egg takes about 3.5 days to hatch. The young caterpillar emerges by eating away part of the egg shell. After its emergence, it turns around and proceeds to finish up the every bit of the remainng egg shell. The newly hatched has a cylindrical pale greenish body covered with many small tubercles. The head capsule is orange in base color and speckled with dark brown patches.

Newly hatched Dot-Dash Sergeant caterpillars, length: 2mm.
Top: first taste of leaf diet; Bottom: constructing first frass chain

The 1st instar caterpillar feeds from the leaf tip and works its way towards the base on each side of the midrib, which is left protruding. At the tip of this exposed midrib, the young caterpillar also laboriously builds a frass chain which is made up of frass pellets strung together with silk thread. 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 disguise itself with a collection of frass pellets secured with silk on the lamina. After reaching about 5.5mm in about 3 days, the caterpillar moults to the 2nd instar.

One 1st instar caterpillar resting on the exposed mid-rib near its frass barrier, length: 5mm

The body color of the 2nd instart caterpillar is mainly dark brown decorated with small black 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 now mostly dark brown and dotted with a few conical tubercles.
This instar lasts about 3 days with the body length reaching 8-8.5mm.

2nd instar caterpillar, length: 8mm

The 3rd instar caterpillar has slightly longer dorsolateral spines, with the pairs on thoracic segments longer than the rest. Its head capsule is dark brown to black irorated with pale brown tubercles. This instar takes 4-5 days to complete with body length reaching about 12mm.

3rd instar caterpillar, early in this stage, length: 8mm

3rd instar caterpillar, late in this stage, length: 11mm

Top: A late 3rd instar caterpillar, dormant before the moult to the next instar.
Note the bulge behind the head capsule, this will become the new head.
Bottom: A newly moulted 4th instar caterpillar, lenght about 12.5mm.

The 4th instar caterpillar has much longer dorsolateral spines which are heavily branched. The body is still brown to dark brown in base color but dotted with rather regular and prominent small black patches on each body segment. Besides conical tubercles, the head capsule also carries some short spines. This instar lasts 4 days with body length reaching about 19mm-20mm.

4th instar caterpillar, length: 13.5mm

The 5th and final instar brings about a drastic change in appearance. The body surface still has the same regular dark patches set against a light brown base color, but now the branched dorso-lateral spines are very well developed on all body segments with those on the meso- and metathorax being the longest. Newly moulted caterpillar has biege to light brown translucent spines, but these will change to light green and then green as the caterpillar grows. Parts of the body surface will also change from brown to green in tandem.

5th instar caterpillar, early in this stage, length: 20mm.
The old 4th instar head capsule can be seen a short distance behind the caterpillar.

Two views of 5th instar caterpillar, early in this stage, length: 20mm.

There is no prominent saddle mark on the 5th abdominal segment as typical in many Athyma spp. Instead, the dark patches which occur on all body segments are enlarged and more prominent on the 5th abdominal segment. The black to dark brown head capsule has much longer and pointed spines. 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 vlews of a 5th instar caterpillar, with spines turning green, length: 20mm

5th instar caterpillar, mostly green in appearance, late in this stage, length: 35mm

A sequence of a few bites taken by a Dot-Dash Sergeant

The 5th instar lasts for 7-9 days, and the body length reaches up to 35-40mm. On the last day, the color of the body and the spines changes with a gradual change to white with yellowish tinge. The caterpillar ceases feeding and wanders around for almost half a day for a pupating site which is typically a branch or a stem. Once a suitable spot is found, the caterpillar spins a silk pad, and from which it hangs vertically to take on the pre-pupatory pose. For the most part of this immobile pre-pupal phase, the caterpillar adopts a curled-up posture (see pic). When it is within a few hours to pupation, the caterpillar gradually relaxes to a more upright posture, and at this time, waves of contraction starts to ripple from the posterior to the anterior end, until the pupation event kicks in.

5th instar caterpillar, last day in this instar with color changes taking place

Two pre-pupatory larva (already attached to the silk pad) in curld-up posture.

Two vlews of a pre-pupatory larva as it gradually adopts an straightened posture as a
prelude to the pupation event.

Pupation takes place a day later. The pupa suspends itself from the silk pad with no supporting silk girdle. When disturbed, the abdominal segments flex laterally. Fresh from the pupation, it is almost silky white. Within the first one or two hours, certain segments and parts are darkened while the remaining parts will gradually take on a beige-silvery shine in hours ahead. The pupa has a pair of long and slight curved cephalic horns, about 4-5mm. Dorsally, there are two processes curved towards each other, with one larger and dark in color. Length of pupae: 25-30mm (counting the cephalic horns).

A pupation sequence of a Dot-Dash Sergeant

Three views of a pupa of the Dot-Dash Sergeant.

After about 6.5 days of development, the pupa turns black in the wing pad area as the development within the pupal case comes to an end. The spots and streak on the forewing upperside are also discernible. The following day, soon after day break, the adult butterfly emerges from the pupal case.

An eclosion sequence of a Dot-Dash Sergeant

A newly eclosed Dot-Dash Sergeant

Another newly eclosed Dot-Dash Sergeant, showing us the undersides.


  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.

  • The Butterflies of Hong Kong, M. Bascombe, G. Johnston, F. Bascombe, Princeton University Press 1999

Text and Photos by Horace Tan

22 November 2008

Why Do Butterflies Puddle?

Puddling Butterflies - Why Do they Do It?

What is puddling?

The term "puddling" refers to the process in which butterflies 'sip' from puddles of water, mud, dung or carrion on the ground. Many species of butterflies are often encountered with their proboscis unfurled and probing into the ground to take in water and nutrients. At the muddy or sandy puddle (often tainted with animal urine or excreta), the butterfly sips water rich in mineral salts and other essential nutrients (mostly sodium chloride and nitrogen-rich solutions) that have leached from the surrounding soil and rocks. Male butterflies do more puddling than females.

Why do butterflies puddle?

The commonest explanation for this is that they are taking in water and nutrients. The dissolved salts and minerals may be used to make pheromones (that the male uses to attract females) and sperm. The main stimulant for puddling is sodium. The diet of adults (primarily nectar and fruits) lack sodium/salt, and the hostplants that they feed on in their younger larval stages do not provide enough sodium either. Sodium is vital for many physiological functions, including digestion, excretion, reproduction and flight. The males have to sustain high activity levels to be able to fly around and locate receptive females, so they have a need for higher energy and metabolism levels. Indeed, the males of many species are known to be more active and faster in flight than females.

So what is the function of sodium extracted during puddling?

Males seem to benefit from the sodium uptake through mud-puddling behaviour with an increase in reproductive success. Sodium is passed by the males to the females during mating. Males transfer this sodium and amino acids to the females together with the spermatophore during mating, as a nuptial gift - it enhances reproductive success. This nutrition also enhances the survival rate of the eggs.Each male can mate with multiple females, so with each copulation, the sodium/nutrient stock is depleted and he will have to puddle again.

Do butterflies of both sexes puddle?

It is usually the younger males that puddle. Females are known to puddle, but that is not the norm. There are various costs and risks associated with puddling, like predation or parasitism, and extra energy utilised. The females minimise these risks by not puddling. By not needing to puddle, they can focus their energies on obtaining more of the other kinds of nutrients, hunting out better oviposition sites, and on laying healthier, more fertile eggs.

How long is the puddling process?

A butterfly can puddle from anything between a few seconds to an hour or more, depending on a variety of factors. During the puddling process, butterflies suck the nutrient rich fluids through their proboscis, and "filter" it within their systems to extract the needed chemicals.

Where does the excess fluid go?

Obviously, fluid ejection results from a need to pass great quantities of soil moisture through the gut in order to extract sufficient useful, but dilute, chemicals. If a particular puddling butterfly is closely watched, one can often see sudden, regular ejections, even squirts, of fluid from the end of the abdomen. These regular ejections of fluid can sometimes be powerful enough to reach several body lengths away from the butterfly!

A close-up of the ejected fluids from the abdomen of a puddling Fivebar Swordtail

Are there any dangers associated with puddling?

Some species of butterflies observed during puddling appear to be in drunken stupor, especially those that have been puddling for a long time. The butterflies appear to be intoxicated on whatever they have been puddling on and become oblivious to their surroundings. This makes them very vulnerable to predatory or parasitic attacks.

Is puddling a social activity?

Probably not in the way we humans define a social activity. However, whenever damp patches of sand or soil is rich in animal excretions or fermenting organic matter, a lucky observer can often encounter a large congregation of various species of butterflies puddling at the same spot - often jostling with each other for the best positions to puddle. If disturbed, the entire congregation erupts in a cloud of colour as their liquid buffet party is interrupted, only to settle down very quickly again to puddle as soon as any perceived threat is over.

A single-species congregation of puddlers. These are Three Spot Grass Yellows

Butterflies of most of the families do puddle, although the Papilionidae, Pieridae, Nymphalidae and Lycaenidae are most often observed to puddle quite readily. Many species, usually powerful flyers which rarely offers an observer a chance to view or photograph them when they are in flight, allow a much better chance for close-quarters observation when they are puddling.

Text by Khew SK with contributions from Anthony Wong ; Photos by Khew SK, Terry Ong, Mark Wong & Anthony Wong

16 November 2008

Life History of the Chocolate Royal

Life History of the Chocolate Royal (Remelana jangala travana)

Butterfly Biodata:
Genus: Remelana Moore, 1884
Species: jangala Horsfield, 1829
travana Hewitson, 1865
Wingspan of Adult Butterfly: 35mm
Caterpillar Host Plants:
Eurya acuminata (Theaceae)

Physical Description of Adult Butterfly:
Above, the male is a deep lustrous purple, with broad brown to dark brown bordering on both wings; the female is paler, and differs from the male also in that the basal portions of spaces 2 and 3 on the forewing are entirely purple. The under surface is dark brown, with conspicuous end-cell bars and a narrow, darker brown, post-discal line on both wings. The two prominent black tornal spots (the one in space 1a larger than the other in space 2) on the hindwing are crowned with brilliant metallic green scaling. Each hindwing has two white-tipped tails of equal length at veins 1b and 2.

Field Observations of Butterfly Behaviour:
This species is is rather rare in Singapore in recent times and sightings have been very infrequent over the last few years. Its occurrences appear to be restricted to a few areas in the the Central Catchment Nature Reserve.

Early Stages:
The host plant, Eurya acuminata, has been described in the life history article for Narrow Spark. Thus far, it has been recorded as the local host plant for Narrow Spark, Chocolate Royal and Ambon Onyx. The caterpillars of Chocolate Royal feed on flower buds of this plant almost exclusively in all four instars. The only exception being in the final instar when leaves are also eaten if flower buds become scarce. It is possible that Chocolate Royal has at least one other host plant locally. Once, a female was observed to oviposit an egg on an Ixora bush. Unfortunately the young caterpillar did not survive past its first instar then.

Host plant : Eurya acuminata
On a flowering host plant in the nature reserve, the mother butterfly was observed to lay eggs singly on the underside of a number of leaves. Each egg is white, but with a strong greenish tinge when freshly laid; circular
and covered with rather large hexagonal pits. The diameter is about 0.7mm.

An egg of the Chocolate Royal. Left: fresh egg; Right: empty egg shell.

1st instar caterpillar, newly hatched, length: 0.9mm

It takes 2.5 to 3 days for the egg to hatch. The young caterpillar nibbles away the upper portion of the egg shell to emerge. With a length of about 0.9mm, it is cylindrical with very long setae (hairs) and pale yellow in base color. Yellowish brown bands run dorso-laterally along its body. As it grows, the body assumes the more typical onisciform (woodlouse) shape.

1st instar caterpillar, length: 2mm

The 1st instar caterpillar finds its way to nearby flower buds and feeds by boring a hole into a flower bud and eating the interior flower parts. After 3 days of growth, and reaching a length of about 2.5mm, its moults to the next instar. The second instar caterpillar has shorter hairs covering its body. The prothoracic shield is roughly diamond in shape and black to dark brown in colour. The prominent dorso-lateral yellowish brown bands were present initially but they fade away during this instar which lasts about 4 days. As the bands fade away, the entire body assumes a light green coloration. The inconspicuous dorsal nectary organ can be seen with a close-up examination.

2nd instar caterpillar, early in thist stage, length: 2.9mm

2nd instar caterpillar, length:5mm
2nd instar caterpillar, late in this stage, length: 7mm

The 2nd instar caterpillar reaches a maximum length of about 7mm. The moult to the 3rd instar brings few obvious changes. The entire body is now covered in very shot fine hairs, and a dorsal nectary organ becomes prominently marked in reddisk brown with a central white patch. The 3rd instar takes 3 days to complete with the body length reaching about 12-13mm.

3rd instar caterpillar, early in this stage, length: 7.5mm

3rd instar caterpillar, late in this stage, length: 13mm

The 4th (and final) instar caterpillar has the same general appearance as the 3rd instar caterpillar. The prothoracic segment is covered with light brown spot while the prothoracic shield is yellowish brown in contrast. This takes about 4 days to complete with the body length reaching 21-22mm. As it grows, the caterpillar becomes more greenish in coloration. Nearing the end of this instar, the caterpillar ceases feeding, and its body shrinks in length. It finds its way to a leaf and takes up a position on the surface to become an immobile pre-pupa.

Close-up views on parts of a 4th instar caterpillar.
Left: the first two horacic segment showing the diamond-shaped prothoracic shield;
Right: dorsal nectary organ

4th instar caterpillar, early in this stage, length: 13mm

4th instar caterpillar, late in this stage, 22mm

The pre-pupatory caterpillar prepares for pupation by spinning a silk girdle and a silk pad to which it attaches itself via claspers. Pupation takes place after about 1 day of pre-pupal stage. The pupa has the typical lycaenid shape, though somewhat wider in proportion, and a length of about 11.5-12.5mm. It is entirely jade green in coloration.

Two views of a pre-pupa of the Chocolate Royal with the silk girdle featured

Two views of a fresh pupa of the Chocolate Royal

Six days later, the pupa becomes darkened in color signaling the imminent emergence of the adult. The uppersides of the forewings become visible through the now transparent pupal skin. The next day the adult butterfly emerges from the mature pupa.

Two views of a mature pupa of the Chocolate Royal

A Chocolate Royal resting on the underside of a leaf

Another Chocolate Royal found in the nature reserve


  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.

  • The Butterflies of Hong Kong, M. Bascombe, G. Johnston, F. Bascombe, Princeton University Pres 1999
Text and Photos by Horace Tan