27 November 2007

Life History of the Yellow Glassy Tiger

The Yellow Glassy Tiger (Parantica aspasia aspasia) is closely related to the two Glassy Tiger species found in Singapore. Although it was recorded as extant in Singapore, the Yellow Glassy Tiger has not been seen in the past two decades or more, and feared to be extinct in Singapore.

ButterflyCircle member Goh LC from Kuala Lumpur was fortunate enough to record the early stages of the Yellow Glassy Tiger. Below are his photos and observations of the life history of this pretty Danainae butterfly.

Butterfly Biodata :
Genus : Parantica (Moore, 1880)
Species : aspasia (Fabricius, 1787)
Subspecies : aspasia (Fabricius, 1787)
Common name : Yellow Glassy Tiger
Wingspan of Adult Butterfly : 60 – 75mm
Caterpillar Host Plant : Raphistemma sp.

Physical Description of Adult Butterfly :
The ground color of the wings is predominantly bluish grey, with the usual black markings of the Parantica species. Each wing has a bright yellow basal patch, that on the hindwing covering about half of the wing surface. Field Observations of Butterfly Behaviour : This butterfly is not uncommon, and frequents forested areas rather than open country. It flies slowly and often glides in mid air. While at rest, it hangs upside down on the dried branches usually with their wings folded shut.

Special Points of Interest :
This species demonstrates both Batesian* and Mullerian** mimicry. The female Wanderer (Pareronia valeria lutescens) mimics the Yellow Glassy Tiger for protection from predators. When the female Wanderer is foraging for food, or looking for a host plant to oviposit, it flies and behaves like the Yellow Glassy Tiger. But when alarmed the Wanderer takes off in a very capable fashion. This is an example of Batesian* mimicry.

Female Wanderer (Pareronia valeria lutescens)

In an example of Mullerian** mimicry, the male of day flying moth, Cyclosia pieridoides shares a similar appearance to the Yellow Glassy Tiger when in flight. Interestingly, the female of this species of moth mimics the Smaller Wood Nymph (Ideopsis gaura perakana), another distasteful Danainae. Both the Yellow Glassy Tiger and the Smaller Wood Nymph were recorded in Singapore by the early authors, but these species do not appear to exist on the island, as they have not been observed for the past two decades or so.

* Batesian mimicry : In this type of mimicry, the mimic not only looks like the model, but also behaves like it. This disguise increases the chances of the mimic being mistaken for the distasteful model which then gives it some “immunity” as it is avoided by its predators.

** Mullerian mimicry : A strategy that has evolved among butterflies (and moths) is for all members of a group to resemble each other and also be unpalatable. This approach spreads the chances of any one butterfly (or moth) being eaten over a larger number of species, and over a larger number individuals within a species. When a bird catches any one of these individuals, it quickly learns to keep away from all the species within the group. This type of mimicry is referred to as Mullerian mimicry, after Muller who first described it.

Early Stages :
The female oviposits a single spindle-shaped egg, usually on the underside of a leaf of the host plant. The egg is white in color, measuring 1 x 2mm high.

The egg of Yellow glassy tiger (Parantica aspasia aspasia)

After about 4 days, the caterpillar hatches from the egg, and immediately starts to consume the eggshell completely. The caterpillar then starts to eat the leaf that the egg was laid upon. The 1st instar caterpillar has a smooth round black head. The color of its body is yellowish-green. There are 2 reddish knots in the prothorax near the head and 2 slightly smaller reddish knots in the last abdominal segment. These knots will eventually evolve into the long filamentous processes known as tubercles.

1st instar Yellow glassy tiger caterpillar (4mm)

As it moults into the 2nd instar, the body turns into red colour and white spots start to appear along with a few yellow spots in the prothorax and last abdominal segment. The head remains black colour like it was in the 1st instar. The knots are more prominent in the prothorax and last abdominal segment.

2nd instar Yellow glassy tiger caterpillar (6mm)

In the 3rd instar, the red colour of its body has become richer, the white and yellow spots are more striking. The knots have turned into paired tubercles. The front tubercles are white with reddish bases and tips.

3rd instar caterpillar showing its black head, white and yellow spots (10mm)

The 4th instar caterpillar is essentially similarly patterned as the 3rd instar, except it has grown bigger. White spots appear on its black head. The round spots lining its body from thorax to last abdominal segment have turned yellow.

4th instar caterpillar with white spots on its head (24mm)

The final instar caterpillar is similar to 4th instar caterpillar, except the colours are more defined and the tubercles are longer. The red colour of its body has turned darker. It is a neat eater as it finishes one leaf completely before starting on a new leaf.

Final instar caterpillar (30mm)

After a total of 14 days upon hatching from the egg, the caterpillar then goes into half a day of dormant pre-pupation pose. The caterpillar prepares for pupation by curling itself into a ball, and anchoring itself by its cremaster to a variety of perches including the leaves or stems of the host plant.

Pupa of the Yellow Glassy Tiger (9 x 15mm)

The pupa is light green with black spots on the abdominal segment of the pupa after 1 day. The silver spots will then appear on the wing and head segments of the pupa after 2 days. After about 8 days, the pupa shell turns transparent and the wings of the butterfly can be seen through the pupa shell. Upon eclosion, the adult butterfly emerges and hangs its wings out to dry, as it pumps fluids into the wings to expand them. When its wings are sufficiently hardened, it opens and closes them as if to test them for flight.

Text and Photos by Goh LC & Khew SK

19 November 2007

The Silverlines of Singapore

A male Club Silverline perches on a flower

The Silverlines belong to the genus Spindasis. The butterflies are distinguished by the silvery markings on the undersides and the hindwings possess two tails. Males of the species are usually with iridescent blue or purple tinge with a broad border on the forewings, whilst females are either brown, or a pale blue. Many species in the genus have an orange tornal patch with black spots on the underside of the hindwings. Females are typically larger with the forewings more rounded at the apex. Species of the genus are distributed from Sri Lanka to Japan, the Philippines and in South East Asia.

The female of the Long Banded Silverline (Spindasis lohita) is described to oviposit on a host plant on which aphids or scale insects live, and which has a nest of the ant Crematogaster rogenhoferi which attend them. The newly hatched larva seeks protection from the ants which build a nest shaped like an aircraft hangar on a branch or amongst leaves with wood flakes. The larva lives in the ants nest from which it emerges during the night to feed. The larva is always attended by a few ants. The larva is described to be dark green or brown, mottled with lighter shades and pale orange spots. Pupation takes place in a small rough cocoon made of leaves spun with silk. The pupa has no silken girdle and is hooked onto the wall of the next only by the cremaster.

Known host plants of the species are Dioscorea pentaphylla, Terminalia paniculata, Xylia sp., Psidium guayava (Guava), Glochidion rubrum Mallotus japonicus, Rhamnus formosana, Rumex crispus and Rhus javanica.

In Singapore, only two species of the genus Spindasis are known to exist. These are :

  • Long Banded Silverline (Spindasis lohita senama)
  • Club Silverline (Spindasis syama terana)

A male Long Banded Silverline opens its wings to sunbathe in the afternoon sun

In the male of the Long Banded Silverline, the dorsal area of the forewing and almost the whole of the hindwing is shot with purple blue. The pale yellow underside is traversed by five or six silver lines which are broadly edged with dark red.

The Long Banded Silverlines like to perch and stay quite still. The top right shot shows an individual puddling on damp seepage.

The Club Silverline can be distinguished from the former species by the basal streak on the forewing below. The colour of the silver edging may be black (most often) or dark red (rarely).

Like the Long Banded Silverlines, the Club Silverlines often stop to perch on grasses. The first shot shows an individual feeding on its favourite nectaring plant - the flowers of the Mile-a-Minute creeper (Mikania cordata)

The butterflies are often seen in the early morning hours and late afternoon hours, feeding on flowering plants. The flowers of the Mile-a-Minute (Mikania cordata) are the usual favourite. The butterflies are fast flyers, but often stop to perch on a few favourite perches to rest. In the later part of the afternoon, they often open their wings flat to sunbathe.

A Club Silverline opens its wings to sunbathe.

The two species are quite widely distributed on Singapore island, and also on Pulau Ubin and Tekong, but they are not common.

Text by Khew SK ; Photos by Sunny Chir, Horace Tan, Sum Chee Ming & Khew SK

References :
  • Butterflies of the Malay Peninsula 4th Edition : AS Corbet & HM Pendlebury
  • Butterflies of West Malaysia and Singapore 2nd Edition : WA Fleming
  • Butterflies of Thailand 1st Edition : Pisuth Ek-Amnuay
  • Life Histories of Asian Butterflies Vol 2 : Suguru Igarashi & Haruo Fukuda
  • Malaysian Butterflies - An Introduction : Yong Hoi-Sen

11 November 2007

Life History of the Purple Duke (Eulaceura osteria kumana)

Butterfly Biodata :
Genus : Eulaceura Butler [1872]
Species : osteria (Westwood, [1850])
Subspecies : kumana (Fruhstorfer, 1913)
Wingspan of Adult Butterfly : 60mm
Caterpillar Host Plant : Gironniera subaequalis

Physical Description of Adult Butterfly : The forewing of the adult butterflies is strongly falcate and the hindwing produced at the tornus. Males are pale purple brown above with a white discal fascia. The female is dull ochreous brown with obscure while fasciae in the distal halves of both wings.

Field Observations of Butterfly Behaviour : Adult butterflies often fly rapidly along jungle paths and settle upside down on the undersides of leaves with their wings folded shut. When disturbed, the butterfly will zip off and display the same behaviour on the next leaf, usually flying short distances. In the early morning hours, both the males and females are more likely to stop on the uppersides of leaves with wings opened flat to sunbathe.

Early Stages :

The female oviposits a single egg, usually on the underside of a leaf of the host plant. The egg is pinkish in colour, almost round with vertical ribs running down the length of the egg.
Egg of the Purple Duke (Eulaceura osteria kumana)

After about 3 days, the caterpillar hatches from the egg, and immediately starts to consume the eggshell completely. The caterpillar then searches for the younger leaves of the host plant and starts to eat the softer young shoots on the host plant.

The 1st instar caterpillar has a smooth round head with lateral dark and light green stripes running the entire length of its body. It has a forked 'tail' which is a feature of this species in all the instars.
1st instar Purple Duke caterpillar with its smooth rounded head

As it moults into the 2nd instar, the lateral green stripes are still there, but the head now takes on forked processes which are dark in colour, giving it an appearance of having 'antlers'. The caterpillar tends to hide on the undersides of the leaves of the host plant.
2nd instar caterpillar showing the black "antlered head" and forked tail.

In the 3rd instar, the black 'antlers' are now more defined, but with light pink extremities. The green stripes of the early two instars are now replaced with two lateral green bordered yellow stripes running down the side of the caterpillar's body. There is a pattern of yellow spots over the entire body.
3rd instar caterpillar showing its black antlered head and sporting yellow/green spotted markings on its body.

The 4th instar caterpillar is essentially similarly patterned as the 3rd instar, but the forked 'tails' are longer and the 'antlers' have now taken a light salmon colouration. The caterpillar remains on the underside of the host plant's leaf when not eating, and carefully aligns itself with a leaf rib such that it camouflages itself very well.
4th instar caterpillar with its salmon-coloured "antlers"

The 5th and final instar caterpillar sports two lateral salmon-coloured stripes which start from the base of the 'antlers' and runs the entire length of the body to the forked 'tails'. Alternate transverse light and dark green bands can also be seen running down the body of the caterpillar, perpendicular to the lateral stripes.

5th instar caterpillar Note the twin lateral stripes. Inset : Close up of the caterpillar's head.

After a total of 38 days upon hatching from the egg, the caterpillar then goes into a day of dormant pre-pupation pose. The caterpillar prepares for pupation by anchoring itself well on the underside of a leaf. Unlike many other species which has a girdle to support the pupa, or where the caterpillar curls up in a pre-pupation pose, the caterpillar of the Purple Duke remains flat on the underside of the host plant and keeps a low profile staying very close to the leaf.
Pre-pupation pose of the caterpillar. It remains dormant in this position for about 24 hours.

The pupa is light green with a single yellow lateral stripe down the back of the pupa. The head takes on a short horned appearance. The pupa hangs from its cremaster with its head facing downwards.

Pupa of the Purple Duke. On the left photo, note the head of the caterpillar discarded as it transforms from a biting/chewing caterpillar into a pupa within which the process of metamorphosis changes it into a nectar-sucking butterfly with no biting mouth parts.

After about 8 days, the pupal shell turns transparent and the wings of the soon-to-be-emerging butterfly can be seen through the pupal shell. A few hours before eclosion, the pupa turns a warm beige with the wings becoming darker and more pronounced and distinctly visible through the pupal shell.
All ready for eclosion. The wing patters of the adult butterfly can be seen through the now transparent pupal case.

Finally, in the late morning, the adult butterfly ecloses and hang its wings out to dry, as it pumps fluids into the wings to expand them. It stays for about an hour or more to ensure that its wings are sufficiently dried and hardened before it takes its maiden flight to search for its mate and continue the circle of life.

Text and Photos by Khew SK

08 November 2007

Saving the Harlequin - Part 2

Following the eggs harvested from the adult Harlequin butterflies, members of ButterflyCircle carefully bred the caterpillars on the host plants. To avoid having an entire batch of caterpillars wiped out due to viruses or other unknown accidental causes, the caterpillars were divided amongst a few members to ensure a high chance of survival of the caterpillars for the next generation of the Harlequins.

Eggs of the Harlequin on a leaf of the host plant.

Breeding caterpillars is not an easy task, particularly for a species where the caterpillars are very small in size. Daily cleaning of the caterpillars' enclosure is needed to ensure that droppings do not become the source for bacteria or other microscopic pathogens which may kill off the caterpillars due to disease. A fresh supply of leaves of the host plant must also be available so that the caterpillars do not starve to death or end up stunted due to insufficient food.

First instar Harlquin caterpillars just hatched from their eggs. Upon hatching the caterpillars immediately consume their own eggshells as their first source of food.

After about 17-20 days of careful care of the caterpillars by ButterflyCircle members, a batch of over 80 of the caterpillars successfully pupated. In this dormant state, the amazing process of metamorphosis takes place in the pupae.

Two caterpillars of different instars feeding on a leave of the host plant. The lower caterpillar is in its 5th instar and on course for pupation.

As we wait with baited breaths for the eclosion of the adult Harlequins where these individuals will hopefully form the next generation of Harlequins with which we will continue to breed and release into habitats which are similar to the one where the species was first found.

Pupae of the Harlequin. In this dormant stage, metamorphosis occurs, as the transformation from caterpillar to the adult butterfly takes place. This typically takes about 7-10 days depending on the species of butterfly.

Several locations have been selected for the translocation of this species and hopefully, the species will continue to survive and thrive in their new home. Will the Harlequin continue to survive and exist on Singapore? Will these next generation of butterflies bred by ButterflyCircle members survive and spawn the next generation and the next?

There are no guarantees in nature. However, the effort taken in conducting this experiment to save the Harlequin from imminent extinction in Singapore as its habitat is being destroyed, is a laudable attempt by ButterflyCircle members, and we hope that we will have at least done our best to try to save a species of butterfly from extinction in Singapore, instead of sitting down and lamenting the loss of another species of our precious fauna to development.

Text by Khew SK ; Photos by Sunny Chir and Horace Tan

06 November 2007

Saving the Harlequin - Part 1

Read about ButterflyCircle's conservation efforts to save the Harlequin (Taxila haquinus haquinus) - a pretty little Riodinid, when its habitat is about to be destroyed for future development.
Top : Male Harlequin Bottom : Female Harlequin
After being absent from the main Island of Singapore for almost 20 years , The Harlequin (Taxila haquinus haquinus) was spotted again in Apr 06. It was previously only known from Pulau Tekong, an offshore military-controlled island to the north-east of Singapore island.
This species of the Riodinidae tends to prefer heavily shaded localities where its host plant can be found. The adult butterfly flits from leaf to leaf, generally at low level bushes, often with half-opened wings.
Where it was observed on the main island was in an area which was not a gazetted nature reserve and hence was not protected from future development. After about a year of monitoring the site, a colony of the species was found to be thriving in that locality. However, the butterflies remained within the vicinity of a very small area, rarely venturing out more than 100m away from its main zone of preference.
Due to the small numbers and localised nature of this butterfly, ButterflyCircle prepared a conservation plan to relocate/propagate the butterfly should its habitat be destroyed. Its hostplant was subsequently identified and the life cycle of the species from eggs to adult butterfly was recorded. Since the rediscovery, regular visits were conducted to monitor the colony and study its habitat to understand this species better. Suitable sites with similar hostplants were scouted and surveyed for the relocation plan. An experimental batch of the adults was relocated on June 07, however for some reason they did not produce any offspring at the relocated site.
Photos showing site clearance at the Harlequin habitat. Trees were chopped down and the area cleared of low vegetation. Clearly, the site was being destroyed and the Harlequins were in danger of losing their preferred habitat.
Some time in Oct 07, members of ButterflyCircle discovered the clearance of the Harlequin site by some contractors. With the imminent destruction of their habitat, it prompted us to launch our immediate action plan to save the species. The plan entails conserving the species by breeding and translocating them to suitable sites for their continued survival. Moreover, the species does not appear to be a nectar feeder, and they are often observed feeding on microscopic substances on leaf surfaces. Nevertheless, after close observation and some trials , a formula for feeding the adults was established and that keep them happy and alive. In return they rewarded us with a number of eggs. The first batch of about 80 Harlequin caterpillars were nurtured by ButterflyCircle members . A local environmentally-friendly organisation was also roped in to collaborate with ButterflyCircle in this conservation project and supplied with a batch of eggs as an alternative breeding source.

Photos by Sunny Chir. Story edited by Khew SK

05 November 2007

Green Oakblue re-discovered in Singapore

As at end of Oct 2007, the Singapore Butterfly checklist stands at 280 species (with 3 subspecies) - not bad for a tiny little island in the sun of about 700 sq km.

There are species which have not yet been confidently identified, and more information would have to be available before these are added to the checklist.

A recent one re-discovered was the Green Oakblue (Arhopala eumolphus maxwelli) which is a forest denizen. The upperside iridescent green of the male of this species is quite characteristic of a group of Arhopala which is green as opposed to purple or blue on the uppersides. The long white tipped tails also distinguish this species from the other two known 'green' Arhopala found in Singapore - A. aurea and A. trogon.

As luck would have it, our hardworking members of ButterflyCircle also managed to discover the host plant of the Green Oakblue and also found eggs of the species. Dr Horace Tan managed to record the life history of this species from egg to adult.

Several known locations within the nature reserves areas of Singapore are home to this species, and only recently have we managed to record the reliable existence of this species in Singapore, without any wild and dubious claims that the species was first found in Singapore when a specimen "flew up to someone's HDB apartment and died in an NSS butterfly collector's flat!"

Special thanks to Sunny Chir for first photographing this species in the wild.

Photo of Green Oakblue courtesy of Federick Ho