27 November 2009

When the Melastoma Blooms...

When the Melastoma Blooms...
The Singapore Rhododendron and Butterflies

The Singapore Rhododendron (Melastoma malabathricum) is a rather amazing plant. Despite being mistakenly named so, it is neither a Rhododendron, not is it confined to Singapore only. From the plant family Melastomaceae, the Singapore (or sometimes also called Straits) Rhododendron is a common plant that springs up almost anywhere where land is cleared, or along open forest paths. The seeds of this plant are dispersed mainly by birds and mammals that feed on its rather sweet fruits, and the plant appears as commonly in the nature reserves as well as urban parks and gardens.

Though an under-appreciated plant by horticulturists, the Singapore Rhododendron is a favourite with bird watchers and butterfly enthusiasts. This is because the flowers and fruits are targeted by birds, butterflies and small mammals. In particular, the Scarlet Backed Flowerpecker is a regular visitor to fruiting Melastoma bushes.

The Singapore Rhododendron usually grows as a "weed" in untended areas, normally up to a metre high, and if left to grow, can reach heights of up to 3 metres. It is a small shrub, that has tiny scales on its branches and petioles. The leaves are narrow and lanceolate, about 5-10 cm long, usually with 3 prominent veins running from the base.

The flowers are light pink-purple, with elbowed anthers surrounding the style, and are borne in clustered inflorescences. The fruit is interesting, a sort of pod, usually about 1.5 cm long, which is covered in small bumps and topped with a persistent calyx.

The greenish pod splits open halfway and flips over to reveal a fleshy deep purple structure studded with numerous (about a thousand) tiny seeds, and is usually 5-sectioned. The fruits are berry-like and break open irregularly. The seeds stain the mouth when eaten, and is sweet and slightly astringent.

A Purple Duke extends its proboscis deep into the fruit of the Singapore Rhododendron. Note the white seeds covering the fruit

The Singapore Rhododendron and Butterflies

Whilst butterflies are occasionally observed to feed on the nectar of the purple-pink flowers, the primary pollinators appear to be bees and wasps.

A small bee approaching the flower of the Singapore Rhododendron for nectar

It is the ripening fruits that are irrestible to butterflies, and when a bush has many such ripened fruits, there will often be swarming with butterflies of the Nymphalidae and Lycaenidae families.

The Colonel (Pandita sinope sinope), a Tawny Palmfly (Elymnias panthera panthera) and a Grey Pansy (Junonia atlites atlites) feed on the Singapore Rhododendron fruits

From many such encounters, ButterflyCircle members have observed that many butterflies that feed on the sweet ripened fruits can sometimes be so intoxicated as to be able to be picked off the fruits with our fingers! They can stay still and continue feeding for long periods of time, allowing the photographer to shoot many shots of a species that is usually skittish and difficult to approach.

A Commander (Moduza procris milonia), a Common Palmfly (Elymnias hypermnestra agina) and a Grey Sailor (Neptis leucoporos cresina) feeding on the fruits of the Singapore Rhododendron

Interestingly, butterflies of the Papilionidae, Pieridae, Riodinidae and Hesperiidae families seem to have less preference for the fruits of the Singapore Rhododendron.

A female Malay Baron (Euthalia monina monina) perched on the fruits of the Singapore Rhododendron

For the butterflies that feed on the ripened fruits, they often have to share the sweet bounty with ants, bees and wasps. The latter two feeders tend to also scare the butterflies away as they barge in onto the fruits.

A Yellow-vented hornet (Vespa analis) helps itself to the fruits of the Singapore Rhododendron

After having their fill of the fruit juices, many of the Nymphalidae, particularly from the genera Tanaecia and Euthalia, will rest in nearby shady spots or sunbathe with their wings opened on sunlit leaves. This gives further opportunities to observe and photograph the butterflies when they are slightly more lethargic than usual.

An Acacia Blue (Surendra vivarna amisena) feeds on the ripened fruit of the Singapore Rhododendron

The ripened fruits tend to be viable to attract butterflies for quite some time - often up to a week or more, as the sugary substance that the butterflies like to feed on appear to regenerate itself during the humidity of the night or after a short shower. During the daytime, the sun dries up the fruits, where it becomes less attractive to the butterflies. We've observed butterflies probing their proboscis deep into the edges of the fruit shell, where the sugars are probably still liquid enough to be imbibed by the butterflies.

A female Purple Duke (Eulaceura osteria kumana) feeds on the ripened fruit of the Singapore Rhododendron next to a goblet-shaped fruit that has yet to ripen

Besides providing a food source for the adult butterflies, the Singapore Rhododendron is also the known host plant to the Horsfield's Baron (Tanaecia iapis puseda) and two Lycaenids - the Long Banded Silverline (Spindasis lohita senama) and Semanga superba deliciosa. The caterpillars of all three species feed on the leaves and shoots of the plant.

A female Horsfield's Baron (Tanaecia iapis puseda) oviposits on the leaf tip of the Singapore Rhododendron, and the 5th instar caterpillar of the Horsfield's Baron

Two pretty Lycaenids - The Long Banded Silverline (Spindasis lohita senama) and Semanga superba deliciosa whose caterpillars depend on the Singapore Rhododendron as one of their caterpillar host plants

And so the humble "weed", the Singapore Rhododendron is a very versatile plant, critical to the survival of many butterfly species in Singapore and South-East Asia, by providing nectar, sugars from the fruits and leaves for the caterpillars.

Text by Khew SK : Photos by Khew SK

21 November 2009

Life History of the Glistening Caerulean

Life History of the Glistening Caerulean (Jamides elpis pseudelpis)

Butterfly Biodata:
Genus: Jamides Hübner , 1819
Species: elpis Godart, 1824
Sub-species: pseudelpis Butler, 1879
Wingspan of Adult Butterfly: 30mm
Caterpillar Local Host Plants:
Saraca cauliflora (Leguminosae, common name: Yellow Saraca); Lepisanthes amoena (Family: Sapindaceae).

A Glistening Caerulean sampling a water droplet on a leaf bud.

Physical Description of Adult Butterfly:
Above, the male is pale shining sky blue, with thread-thin forewing border and absence of submarginal markings on the hindwing. The female is pale blue with forewing border ending at mid costa. Beneath, the narrow striae are white and straight, or nearly so. Being a member of the elpis subgroup (of the celeno group), the Glistening Caerulean also has the post-discal band on the forewing underside completely dislocated at vein 3. On the hindwing, the second white stria from the base in space 7 is about mid-way between the second and third striae from the base in the cell. Each hindwing features a black-centred orange-crowned tornal spot, rather large submarginal orange markings along veins 1b and 4, and a white-tipped filamentous tail at the end of vein 2.

A male Glistening Caerulean giving us a full view of its glistening blue upperside.

A Glistening Caerulean perching on a leaf of the Yellow Saraca.

Field Observations of Butterfly Behaviour:
This species is rarely encountered in Singapore. It is re-discovered in the early part of this year in an urban garden where a small colony was found to be breeding on the two host plants present. At this site, the males were observed to be flying around in sunny weather, and puddling on wet ground. A number of females were also with sighted carrying out their oviposition routines on flower buds of both host plants.

A Glistening Caerulean perching on a broken twig.

Early Stages:
The 1st local host plant, Lepisanthes amoena (Kayu Matahari) is a small to medium-sized tree with imparipinnate (pinnate with a terminal leaflet) leaves. Leaf-like pseudo-stipules are present. The whitish flower buds are globular and occur in terminal panicles. Fruits are tri-lobular and turn reddish brown when ripened. Early stages of the Glistening Caerulean feed on flower buds and flowers of this plant.

Host plant: Lepisanthes amoena: Flower buds (left); Fruits (right).

A mother Glistening Caerulean laying her eggs on flower buds of Lepisanthes amoena.

The 2nd local host plant, Saraca cauliflora (Yellow Saraca) is a small to medium-sized tree with pinnate leaves in 4-6 pairs. The flowers are orange-yellow in large clusters on trunk or branches. Early stages of the Glistening Caerulean feed on flowers parts of this host plant.

Yellow Saraca: cauliflorous flowers (left); pinnate leaves and seed pod (right).

A mother Glistening Caerulean laying her eggs within a cluster of Yellow Saraca flowers.

Eggs of Glistening Caerulean are laid singly on flower buds or flower parts of the host plant. The small pale green egg is disc-like and about 0.4-0.5mm in diameter. Its surface is covered with a reticulated pattern of intersecting ridges.

Eggs of the Glistening Caerulean laid on flower parts. Left: on Lepisanthes amoena;
Right: on Yellow Saraca.

The egg takes 2-3 days to hatch. The young caterpillar emerges after nibbling away sufficiently large portion of the egg shell. Measured at a length of about 0.8-0.9mm, its pale yellow body is cylindrical in shape, sporting long fine setae (hairs) and a dark head capsule. There is also a dark prothoracic shield and an anal plate.

Bottom: A newly hatched caterpillar of the Glistening Caerulean, length: 0.8-0.9mm.
Top: A late 1st instar caterpillar, 1.9mm.

The newly hatched grazes on the surface of flower petals or bores into a flower bud for the goodies within. After about 2 days of growth and reaching a length of about 2.5mm, the caterpillar moults to the next instar.

Boring into flower parts. Left: a newly hatched on Yellow Saraca flower.
Right: a 2nd instar caterpillar on a flower bud of Lepisanthes amoena.

The 2nd instar caterpillar has numerous short setae with dark base and this gives the pale yellow body surface a heavily dotted appearance. From this instar onwards, the small diamond-shaped prothoracic shield takes on a pitch black coloration.
This instar lasts about 2 days with the body length reaches up to 4.5mm.

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

The 3rd instar caterpillar resembles the 2nd instar caterpillar with body color pale to dark yellow. Both the dorsal nectary organ (on the 7th abdominal segment) and tentacular organs (on the 8th abdominal segment) are barely discernible.
The 3rd instar takes 2.0 days to complete with the body length reaching about 7.0mm.

3rd instar caterpillars. Top: newly moulted, 4.3mm. Bottom: 5.5mm.

Still covered with numerous fine setae on the body surface, the 4th (and final) instar caterpillar has taken on a darker shade of yellowish brown. The dorsal nectary organ is now prominently marked with an encircling dark brown patch. Another noticeable change is in the diamond shaped prothoracic shield which now has a vertical split.

4th instar caterpillar feeding on Yellow Saraca flowers.
Top: early in this stage, length: 7.5mm. Bottom: late in this stage, length: 12mm.

After 4-5 days of growth and reaching a maximum length of around 11-12mm in the final instar, the body of the caterpillar gradually shrinks, and finally takes on a dark pinkish to reddish brown coloration. All bred specimens chose to enter their pre-pupatory phase in tight pockets of space within leaf debris. At the chosen spot, the caterpillar readies itself for pupation by spinning a silk girdle and a silk pad. The caterpillar secures itself to the silk pad via claspers on its posterior end.

Two views of an immobile pre-pupatory larva of the Glistening Caerulean.

The girdled down pre-pupa still has the ability to evert its tentacular organs, indicating that
ant-larva association does continue into the pre-pupal stage.

Pupation takes place after one day of the pre-pupal stage. The pupa has the typical lycaenid shape. It is pale yellow to beige in base color with a number brown and black specks. of various sizes. The pupa has a length of about 8-9mm.

Two views of a pupa of the Glistening Caerulean, length: 9mm

Eclosion takes place after 6 days in the pupal stage. The mature pupa gradually darkens in colour the day before. Bluish patches on forewing uppersides become clearly visible in the wing pads of the mature pupa. The extent of these bluish patches reveals the gender of the soon-to-emerge adult.

Two views of a mature pupa of a female Glistening Caerulean.

A newly eclosed male Glistening Caerulean

  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
  • Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

Text by Horace Tan; Photos by Bobby Mun, Sunny Chir, Khew SK and Horace Tan

15 November 2009

Observation Notes on the variability of the female Jacintha Eggfly

Observation Notes on the variability of the female Jacintha Eggfly

A typical Jacintha Eggfly perches on a leaf in an urban hill park

The Great Eggfly (Hypolimnas bolina) has a number of subspecies according to various sources. A quick online research shows about seven subspecies. Thus far, only two of these subspecies occur in Singapore - ssp bolina and ssp jacintha.

A female Jacintha Eggfly oviposits on its host plant, Asystasia gangetica

Whilst subspecies bolina is of particular interest because of its polymorphism of which the individual specimens are highly variable, and at least four principal forms are recorded, which are connected by intermediates. It is so highly variable, that C&P4 records that "it is difficult to find two exactly matching examples"!

A Jacintha Eggfly puddling

Leaving subspecies bolina aside for the moment, this article focuses on the subspecies jacintha or what ButterflyCircle members refer to as the Jacintha Eggfly. It is interesting to note that C&P4 and Fleming, who both published books spanning the last century, records ssp jacintha as "increasingly rare" towards the end of the 19th century, and then almost disappearing altogether. In fact, Fleming's book lists ssp jacintha as "very rare". However, in the 1970's this subspecies began to re-establish itself in the Malay Peninsula "where it interbreeds with ssp bolina giving rise to adults showing a wide degree of intergradation, so that it is often not possible to assign specimens to one subspecies or the other".

A typical f-incommoda female Jacintha Eggfly

Observations made in the late 90's to the early part of the 21st century in Singapore indicate that the ssp bolina is again on the decline, and now being replaced by the more common ssp jacintha. The more distinctive females of ssp bolina with its typical orange forewing patch is now rare, and more often seen only on Pulau Ubin than anywhere else in Singapore, where it was previously common. The ssp jacintha is the more commonly occuring subspecies today.

A Jacintha Eggfly perches on a branch. Note the broad submarginal markings on the hindwing

From contemporary literature, various authors have recorded the female ssp jacintha as having only two forms. These are female f-jacintha and f-incommoda.

A typical male Jacintha Eggfly. The males are almost indistinguishable from the males of the subspecies bolina males

Males are rather similar to the ssp bolina and often indistinguishable. The typical female f-jacintha is apparently the rarer of the two forms, where the female is almost totally brownish grey on the uppersides with the usual white spots on both wings. The f-incommoda with varying blue patches on the forewings and hindwings and light blue subapical spots on the forewings, is more common. Even so, this form is very variable, with the extent of the blue patches varying from very little to significant.

A series of female Jacintha Eggfly, showing the variation in the blue markings on the forewings above as well as the subapical blue spots on the forewing. In the first specimen, the blue patches extend to the hindwings as well.

Of late, another possible form has emerged. This is a female with predominantly brown wings above, with the typical white spots of f-incommoda but with reduced blue tinge on the forewing costal margin. But of note would be the significant large white patches on the hindwing above. This "form" has not been previously observed in Singapore, although this site shows some similar individuals which could suggest that this "form" exists elsewhere in Asia. First seen in at least 3 females bred in captivity, a free-ranging female of this "form" was eventually photographed by ButterflyCircle member Federick Ho in a patch of wasteland to the north-east of Singapore island - suggesting that this "form" may occur in the wild as well.

Shots of the previously unrecorded form of the female Jacintha Eggfly. Note the extensive white patch on the hindwing, which is absent in the two known female forms of the Jacintha Eggfly in Malaysia and Singapore.

In late 2009, I managed to capture a voucher specimen of this new "form" at a site in Punggol, which has been, unfortunately cleared for redevelopment now. The female was found in the vicinity of its host plant Asystasia gangetica a common roadside weed.

A wild-captured voucher specimen of the new form of the Jacintha Eggfly, showing upperside (left half) and underside (right half) of the wings

It will be necessary to document the occurrence of possible new forms of this subspecies of the Eggfly, and indeed, if possible to conduct further breeding observations to see if the ssp bolina and ssp jacintha are two subspecies of the Great Eggfly or just a single subspecies with many different forms!

Until then, if you have photos of the Jacintha Eggfly, particularly showing the uppersides of the female butterfly, please send them to ButterflyCircle at hexaglider@yahoo.com for records.

Text by Khew SK ; Photos by Federick Ho, Khew SK, Loke PF, Sum CM & Terry Ong

References :

  • Bolina World (A Japanese Website)
  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
  • Butterflies of West Malaysia and Singapore, W. A. Fleming, 2nd Edition, Longman Press