Life History of the Narrow Spark

Life History of the Narrow Spark (Sinthusa nasaka amba)



Butterfly Biodata:
Genus: Sinthusa Moore, 1884
Species: nasaka Horsfield, 1829
Subspecies: amba Kirby, 1878
Wingspan of Adult Butterfly: 25mm
Caterpillar Host Plants: Eurya acuminata (Theaceae)

Physical Description of Adult Butterfly:
The adults closely resemble adults of Common Tit, a larger and more common species. Above, the male is dark brown on the forewing with deep blue tinge at basal half, and the hindwing is mostly violet blue with a dark brown costal border. The female is dark brown with a white tornal area bearing black spots in the hindwing. Underneath for both sexes, the post-discal line of narrow ochreous brown stripes is mostly continued on the forewing, but broken on the hindwing. A black tornal spot is present in space 2 and another on the lobe of the hindwing, with the tornal area rather sparsely dusted with metallic green scales.

Field Observations of Butterfly Behaviour:
This small species is rather uncommon in Singapore. Sightings have been localized to a few area within the Central Catchment Reserve Area. Encounters with the adults typically take place in dim lighting condition under forest canopy.

Early Stages:

The host plant, Eurya acuminata, is a small tree with lanceolate or ovate-oblong leaves of length 4-9cm. The leaf has finely toothed margin and net-like tertiary veins. The twigs are round and glabrous (finely hairy). The flowers are minute (less than 0.5cm across) and arranged in 2-5 flowered inflorescence, axillary or along leafless twigs. Juice extract of tender leaves is drunk in some parts of the world to relieve dysentery and diarrhoea. Locally, this plant can be found in secondary forest alongside trails within the Central Catchment Reserve Area.


The host plant, Eurya acuminata, pictured with one female Narrow Spark trying to oviposit on the leaf underside

Eggs are laid singly on the a flower bud or on the stem/leaf adjacent to the buds. Each egg is green in color, small (about 0.4-0.5mm in diameter) and circular with a slightly depressed micropylar. The surface is finely sculptured with intersecting ridges. The egg is almost identical to eggs of Rapala species described in the literatures.

A female Narrow Spark ovipositing near a flower bud of the host plant

An egg of the Narrow Spark, about 0.5mm in diameter.

Three days later, the egg hatches with the young caterpillar eating away the upper portion of the egg shell to emerge. Measured at a length of about 0.8-0.9mm, it is cylindrical in shape, sporting long setae (hairs), a large dark brown head capsule and overall pale yellow body.

Mature egg (left), empty egg shell (right)

1st instar caterpillar, newly hatched, length: about 0.8mm

The 1st instar caterpillar bores into a flower bud and eats the developing flower parts within it. It feeds with its head in first, keeping its rear end close to the entrance for ejecting frass outside the bud. Usually the presence of caterpillar "hidden" in a particular hole is given away by tuffs of fine hair at the hole entrance and the presence of frass nearby.

Left to right, a 1st instar caterpillar re-entering a flower bud for its feast, length: 1.2mm

After 2 days of growth and reaching a length of about 2mm, the caterpillar moults to the next instar. Some caterpillars actually moult within a flower bud. The second instar caterpillar has numerous tubercles covering its body with short fine hairs protruding from them. There are small dark brown spots set against a light brown base color. As the caterpillar grows larger, more and more of the posterior end of its body will remain outside the flower bud as it feeds on the goodies within.


2nd instar caterpillar, late in this stage, length:4mm

The 2nd instar caterpillar reaches a length of about 4.5mm, and after 3 days in this stage, it moults again. Keeping a similar appearance as in previous instar, the 3rd instar caterpillar has more prominent dorsal markings with a brown dorsal line. Tubercles lining the body segments in the sub-dorsal and sub-spiracular locations have become enlarged with tuffs of protruding setae. The typical lycaenid nectary organs (both the dorsal nectary organ and tentacular organs) are now discernible. The 3rd instar takes 3 days to complete with the body length reaching about 8.5mm.


3rd instar caterpillar checking out a flower bud, length: 8mm

The 4th (and final) instar caterpillar still has the same dorsal markings as in earlier instars, but the white diamond-shaped prothoracic shield now has prominent black spots at its 4 corners. Initially the body base color is pale brown with the 1st thoracic segment and the anal plate yellowish green. As the caterpillar grows, as depicted in the 3 figures below, the base color changes to yellowish brown and finally to yellow in the first three days of this instar. The sub-dorsal and sub-spiracular rows of tubercles become translucent to transparent in appearance, with some of them assuming a bluish coloration. Furthermore, as the body base color changes to yellow, the 5th abdominal segment also becomes darkened from the sub-dorsal to sub-spiracular area.

4th instar caterpillar, day 1 of 5 in this stage, length: 10mm


4th instar caterpillar, day 2 of 5 late in this stage, 12mm

4th instar caterpillar, day 3 of 5 in this stage, 14mm

The dorsal nectary organ and the tentacular organs on the 7th and 8th abdominal segments respectively are rather prominent in the final instar caterpillar. On the last day of the final instar, copious amount of clear fluid was observed to be excreted from the nectary organs of the shortened and decolorized caterpillar. These functioning nectary organs suggest a strong caterpillar-ant association in the wild.

The anterior segments of a 4th instar caterpillar, the nectary organs are annotated.

After five days of growth and reaching a maximum length of around 14mm in the the final instar, the body of the caterpillar becomes shortened and decolorized caterpillar. Soon it chooses a spot on the leaf surface to remain stationary and becomes a pre-pupatary larva. At this site, it prepares for pupation by spinning a silk girdle and a silk pad to which it attaches itself via cremastral hooks.


A pre-pupa of the Narrow Spark, showing a finished silk girdle securing it to
the leaf surface, also visible is clear fluid from a final purge.

Pupation takes place after 1 day of the pre-pupa stage. The hairy pupa has a shape typical of most lycaenid species, and a length of about 7.5mm. It is light brown dotted with small dark brown specks.


Two views of a pupa of the Narrow Spark.

Seven 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, allowing one to tell the gender of the soon-to-appear adult. The next day the adult butterfly emerges from the mature pupa.


Two views of mature pupa of the Narrow Spark


A newly eclosed female Narrow Spark resting on a perch


A male Narrow Spark resting on a perch in CCA

Acknowledgments:

I would like to express my gratitude to Prof Hugh Tan of NUS DBS and Ali Ibrahim of Nparks for providing confirmation of the host plant species ID.


References:

• 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

Butterfly of the Month - July 2008

BUTTERFLY OF THE MONTH - JULY 2008
The Branded Imperial (Eooxylides tharis distanti)

This pretty forest butterfly is always present to greet visitors to the nature reserves of Singapore, never failing to delight nature enthusiasts with its bright orange colouration and long white tails. It is often seen fluttering in the shady understorey and thick vegetation, and rarely moving out to bright sunny areas. The Branded Imperial is local in distribution, but is not uncommon. Frequently, a few individuals are observed, frolicking and chasing each other in shady vegetation.

The wings are blackish brown above, with a white tornal patch on the hindwing. The underside is a reddish orange, with an unmarked forewing, with the hindwings featuring large black submarginal spots on the white tornal area which is fringed by an irregular black line, separating the white tornal patch from the orange area of the hindwing.

The eyes are an opaque jet black, as are the antennae, whilst the butterfly has black-and-white banded legs. There are three pairs of tails on the hindwings, of which the one at vein 2 is the longest, often measuring about 1cm in length.

The Branded Imperial has a short skipping flight, as it flits from perch to perch at usually no more than a metre above the ground. As with many Lycaenidae, the tails and 'eyespots' on the hindwings are believed to function as illusionary decoy to fool predators into attacking the tails rather than the vital part of the butterfly. Indeed, if one is to observe the Branded Imperial at rest, individual sometimes move their hindwings up and down and their tails twirl and move in the light forest breeze, giving it an appearance that the combination of the hindwing eyespots and the tails are the head and antennae of the butterfly.

Occasionally, several individuals can be observed feeding on the sap of young shoots of various species of forest plants, where the butterflies are so busy feeding on the sugary-sweet sap that they even allow observers to touch them!

The Branded Imperial's early stages have been recorded on its preferred host plant, Smilax bracteata, a forest climber which is considered a "pest" and a threat to the trees and large bushes onto which the vine climbs and slowly suffocates.

Text by Khew SK ; Photos by Khew SK, Mark Wong and James Chia

Life History of the Hieroglyphic Flat

Life History of the Hieroglyphic Flat (Odina hieroglyphica ortina)


Butterfly Biodata:
Genus: Odina Mabille, 1891
Species: hieroglyphica Butler, 1780Sub species: ortina Evans, 1941
Wingspan of Adult Butterfly: 32mm
Caterpillar Host Plants: Erycibe tomentosa (Convolvulaceae)

Physical Description of Adult Butterfly:
Male is yellow-orange, with yellow-orange markings framed by thick black lines on both wings. Female is paler yellow. The underside markings are similar in pattern but paler. The abdomen of the butterfly is stripped in orange and black. The Hieroglyphic Flat is a very distinctive-looking skipper, with the cryptic patterns reminiscent of the camouflage paint of a German Messerschmitt fighter plane in World War II.

Field Observations of Butterfly Behaviour:
This species is rarely encountered in Singapore. Over the last few years, it has been sighted in a dozen times in various areas in the Central Catchment Area, Southern Ridges and in an abandoned farm land in the west. It is a fast-flyer and can only be observed when the adults stop to feed on flowers and bird dropping, or when the females are carrying out oviposition routines of leaf hopping. When resting, as with other "flat" skippers, the adults have the habit of perching on leaf undersides.


The Hieroglyphic Flat feeding on bird dropping on a board walk (left),
and taking nectar in an open wasteland (right).

Early Stages: The host plant, Erycibe tomentosa, is a woody climber, and locally can be found on hedges, edges of forests and sides of forest trails, in areas such as the Central Catchment Area and Southern Ridges. On one occasion, Sunny Chir, an active Buttercircle member, chanced upon a female laying eggs on the host plant at the edge of the nature reserve, close to a row of private houses.


Host plant : Erycibe tomentosa

The eggs are laid singly at the leaf tip of a young leaf or mid-age leaf. Each egg is white and almost spherical with vertical ridges, and has a diameter of 0.8mm. As with other "flat" (such as the Chestnut Angle) skippers, the mother rubs the tip of her abdomen over the freshly laid egg, resulting in the egg being concealed in a mess of fine brown hairs.


Two views of the hairy eggs of the Hieroglyphic Flat.


Empty egg shell of the Hieroglyphic Flat.

It takes 3 days for the egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 2mm. It has the typical cylindrical shape for skipper caterpillars. It body is yellowish orange with a transverse black line right behind a black bilobed head. After leaving the egg shell, the 1st instar caterpillar makes its way to the leaf edge to construct its first leaf shelter. It rests within the shelter and ventures out to eat the leaf surface nearby. The intake of this diet gives the caterpillar a greenish undertone.


1st instar caterpillar, length: 2mm

A view of the leaves of the host plant, showing the location of an
empty egg shell, and small leaf shelter for the 1st instar caterpillar.

As with some other skipper species, the Hieroglyphic Flat caterpillars have been observed to ballistically eject their somewhat sticky faecal pellets (frass) at speed. In a home breeding environment, this also results in a splatter of frass on the inner side of the container wall next to the leaf shelter.
After 3 days in 1st instar and reaching a length of about 4mm, the caterpillar moults to the next instar within the shelter. It still has the same light yellowish body with a green undertone, but now numerous tiny whitish speckles become apparent. It reaches a length of about 6mm after 5 days of growth in this instar.

2nd instar caterpillar, 4mm


2nd Instar caterpillar, 6mm.


A 2nd Instar caterpillar almost done with the cut of the leaf blade in the construction of its leaf shelter.

The 3rd instar caterpillar has a similar appearance as in the previous instar. The 3rd instar lasts about 3-4 days with the body length reaches 10-11mm. The leaf shelters for the larger caterpillars in 3rd and later instars are made from bringing two edges of the leaf together with sinuous cuts and silk threads, resulting in a ``curry puff'' appearance.

3rd instar caterpillar, early in this stage, length: 7mm


3rd instar caterpillar, late in this stage, length: 10mm
The 4th instar caterpillar looks similar to the earlier instars with the only visible difference being the much more distinctive speckle pattern on its body, and two rows of small black spots dorsally on the first seven abdominal segments, with two spots to each body segment. The 4th instar takes about 4 to 6 days to complete with the body length reaching 17-18mm.


4th instar caterpillar, early in this stage, length: 10mm


4th instar caterpillar, ready to moult to the next stage, length: 15mm.

The head capsule of the final and 5th instar caterpillar has a brown or dark brown base color with pale brown to orange patches. The surface of the head capsule is covered with a layer of short fine hairs. Growth in this stage is rather slow and it takes about 14-15 days to complete with the body length reaching about 24mm.
5th instar caterpillar, newly moulted to this stage, 15mm


5th instar caterpillar, late in this stage, length: 24mm

At the end of 5th instar, the body of the caterpillar gradually shrinks in length. Soon it becomes dormant in its leaf shelter and enters the prepupatory phase which lasts for one day.

Two views of a pre-pupatory larva of the Hieroglyphic Flat.

Pupation takes place within the leaf shelter. The pupa secures itself with its cremaster attached to a short transverse band on the leaf surface, and has a silk girdle. The pupa is mostly green in base colour. It has a short thorax, a rather long abdomen and a pointed rostrum. Length of pupae: 16-18mm.


Two views of a fresh pupa of the Hieroglyphic Flat.

After 9 days, the pupa becomes mostly black in color with the cryptic patterns on the forewing somewhat distinguishable through the now transparent pupal skin. Eclosion takes place the next day.


Two views of a mature pupa of Hieroglyphic Flat.


A newly eclosed Hieroglyphic Flat.

References:

• 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

The Butterfly Proboscis

A Butterfly's Proboscis - Its Lifeline to Survival

Butterflies are well-known for their beauty and grace and are one of the most admired and adored creatures of the insect world. Most people are aware that butterflies do not have chewing or biting mouthparts, nor have any sort of defensive mechanisms which scratch, sting, bite or poke, unlike most other insects. How then do these pretty and harmless insects derive their sustenance for survival?

They feed on a liquid diet through their adult life, imbibing dissolved sugar, salts and other minerals from a variety of sources ranging from flowers, rotting fruit, tree sap, carrion, urine, faeces and so on. Some species are also partial to human sweat and will stop to feed on sweaty forearms, faces and hands of humans who are in the vicinity of these hungry butterflies!

A Malayan Eggfly uses its proboscis to suck up human sweat!

Butterflies feed through a paired tube located at their heads. This paired tube is called the proboscis. The Greek origin of proboscis comes from "pro" (before) and "boskein" (to feed). The word proboscis is pronounced in two different ways, both of which are acceptable - (pro-BOSS-iss or pro-BOSS-kiss). Click on the links to hear the pronunciation of the word proboscis.

Through the amazing process of metamorphosis, the caterpillar's biting/chewing mouthparts - for eating their host plants, transforms into the paired "drinking straw" proboscis. When the butterfly ecloses, besides pumping fluids into its limp wings to expand them, it also has to get its proboscis in working order. As it ecloses from its pupal case, the butterfly's proboscis is in two separate pieces that are joined together by tiny hooks and fringes. The eclosing butterfly has to twist and curl the two halves of the proboscis to create one drinking tube. If, in the event this preparatory function is interrupted, the butterfly can no longer feed, even though it is able to fly, hence condemning it to a short life of hunger and starvation.

Situated between the butterfly's eyes, but below them, is the proboscis. This paired structure, comprising two halves, are hooked together after eclosion, forming a central canal. The proboscis is usually coiled up like a watchspring right against the butterfly's face, to protect it. When in use, it is extended with muscles to probe the nectaries of flowers or other substances. When outstretched in this manner, the proboscis behaves like a drinking straw through which the butterfly draws fluids up and into its body. Commonly 1 to 2 cm long in butterflies, the proboscis can be as long as 30cm(!) in certain Hawkmoths. Indeed, the proboscis of certain species of Hesperiidae (Skippers) are typically longer than the body of the butterfly, sometimes twice as long.

The proboscis of this Hoary Palmer is more than twice as long as its body!

The proboscis appears to be protected by the butterfly's labial palp. The two palpi line up along the butterfly's face, between which the proboscis lie. In certain species' case, the palpi are so hairy as to give the butterfly an appearance of an unshaven face.

When a butterfly finds a potential food source, it unfurls its proboscis and uses its forked tip to investigate the fluids. The proboscis is therefore a very useful tool and particularly well-adapted for the butterfly to reaching deep into flowers for nectar. In the process of feeding on the flowers' nectar, butterflies also transport the pollen from the stamens of a flower to other flowers as the butterfly moves around to feed, thereby helping in the process of pollination. Indeed, butterflies are also one of the agents of pollination and contribute to the propagation of many of the plant species on which the butterflies feed on the flowers.

The proboscis of the Plain Tiger is covered with pollen from the flower, all ready to be transferred to the next flower for pollination, as it goes about feeding on nectar.

The proboscis is also used when the butterflies puddle (the act of feeding on damp footpaths or river banks) where they imbibe dissolved salts and other minerals from the fluids on the ground. The proboscis is similarly used when the butterfly feeds on tree sap, rotting fruit, bird droppings and a whole spectrum of dissolved minerals from these sources that the butterfly requires for sustenance, fertility and energy to go about its daily activities.

The proboscis is very much sized according to the size of the butterfly, with larger butterflies having longer and thicker proboscis whilst the smaller butterflies have thinner and finer proboscis. An interesting observation is that the proboscis of butterflies also come in various colours - ranging from jet black to orange and greens.

A display of multi-coloured proboscis as these butterflies feed on rotting fig fruits on the forest floor.

Text & Photos by Khew SK

Special Acknowledgments to :

• Merriam-Webster Online for the Audio pronounciation clips
  

References :

• Handbook for Butterfly Watchers : Robert Michael Pyle, Houghton Mifflin Company, Boston/New York, 1992