Life History of the Green Imperial

Life History of the Green Imperial (Manto hypoleuca terana)



Butterfly Biodata:
Genus: Manto de Nicéville, 1895
Species: hypoleuca Hewitson, 1865
Subspecies: terana Seitz, 1926
Wingspan of Adult Butterfly: 36mm
Caterpillar Host Plants: Macrosolen cochinchinensis (Loranthaceae)

Physical Description of Adult Butterfly:
Above, the male is shining bluish green, with the apical two-thirds of the forewing, cell and termen border of the hindwing black; tornal margin white and crossed by submarginal spots. The female is dark brown and has white tornal area in the hindwing crossed by conjoined quadrate black spots in spaces 1b and 2. Beneath, both sexes are yellowish orange on the forewing, much paler at dorsum and darker towards the apex. The extent of the yellowish orange coloration on the hindwing differs in the two sexes, with the male having almost complete coverage and that of the female being restricted to the costal area and white elsewhere. The white tornal area contains prominent subtornal markings, with a series of post-discal striae usually reaching vein 6. Each hindwing has a pair of white-tipped tails at ends of veins 1b and 2, with the ones at vein 1b much longer, and the ones at vein 2 about one-third as long.



A male Green Imperial


The upperside of a male Green Imperial


A female Green Imperial


The upperside of a female Green Imperial

Field Observations of Butterfly Behaviour:
This species was confirmed to be still extant in Singapore after a fortunate encounter with a male specimen at the edge of the nature reserve in 2008. It is rare locally as well as in the Malayan Peninsula. Sightings of this species have so far been confined to a few locations within the Central Catchment Nature Reserve, and typically only a single individual appears each time. The fast-flying adults have been sighted taking nectar at flowering plants in the reserves, and perching high near its host plants. An active ButterflyCircle member, Ben Jin, had the good fortune of locating the eggs and caterpillars on the host plant recently. Credit is thus due to him for the discovery of early stages of this stealthy species and making it possible for the life history to be featured in this article.

Early Stages:
The host plant, Macrosolen cochinchinensis, is a parasitic shrub with all parts of the plants glabrous (having no hairs, smooth). The leaves are leathery, opposite, ovate or lanceolate. The early stages of the Green Imperial feed on the young to mid-aged leaves of this parasitic host, with the 1st instar initially skimming the leaf surface and the later instars eating the leaf along the edges.


Host plant : Macroseolen cochinchinensis

Eggs are laid singly on the stem or petiole of a young shoot, or the pedicel in the vicinity of the flower buds of the host plant. The egg is hemi-spherical with a raised dome, the very top of which is the micropylar. Each egg is white and covered with rather large hexagonal pits. The diameter of the circular base is about 1mm.


Two views of an egg of the Green Imperial


Two vlews of an empty egg shell where the raised dome was mostly eaten by the newly
hatched as it made its way out.

It takes about 3 days for the collected egg to hatch. The young caterpillar consumes just enough of the egg shell to emerge. It is pale yellow in coloration, and has a length of about 1.5mm. Long setae (hairs) run along the length of the body dorsally as well as sub-spiracularly. Raised dorsal tubercles are transparent. A large prothoracic shield, in darker shade of brown, can be observed. The newly hatched feeds on the flower parts or the young leaves nearby by skimming the surface. Later instars will feed on the leaf lamina, working their ways along the edges.


Two views of a newly hatched caterpillar, length: 1.5mm.


1st instar caterpillar, length: 2mm.

As it grows in this instar, the caterpillar assumes a greenish (yellowish green form) or a reddish coloration (red form). The 1st instar lasts about 3 days and sees the body length increased to about 3mm.


A 1st instar caterpillar of the yellowish green form, in the vicinity of an egg.


A 1st instar caterpillar of the red form.

In the 2nd instar caterpillar, the dorsal tubercles are reduced in size, and the long dorsal setae seen in the 1st instar are now absent. Its diamond-shaped prothoracic shield is very dark in color. The posterior segments from the 7th abdominal segment onwards are fused together and taper downward to the last segment. Pale brown patches decorates the sides of the body, as well as the anterior and posterior segments.


A newly moulted 2nd instar caterpillar (yellowish green form), eating its old skin.


A red form caterpillar seen just after its moult to 2nd instar.


Two views of 2nd instar caterpillar (yellowish green form), early in this stage, length:4.5mm.

These patches become darker in coloration as the caterpillar grows in this instar. A much darker marking is also present between abdominal segments 4 and 5. It is possible to observe the dorsal nectary organ at this stage, though it is still inconspicuous to the naked eye. The 2nd instar lasts for 3 days with the body length reaches about 6-7mm.


Two views of a 2nd instar caterpillar, later in this stage, length:6mm.



A 2nd instar caterpillar committing a carnivorous act.
The victim is a young caterpillar (late 2nd instar) of Tajuria mantra mantra.

In the 3rd instar caterpillar, the lateral body markings, pale brown to dark brown in cryptic pattern, now dominate the general appearance. In the red form, these lateral body markings have a reddish undertone. The lateral body markings are broken between the 4th and 5th abdominal segments by a black triangular marking. The contrasting green coloration is restricted to the dorsal ridge and subspiracular rim of the body.


3rd instar caterpillar, length: 9.5mm.

As the body grows in size to a length of around 11-12mm, the color of shading on the body darkens. The dorsal nectary organ and the tentacular organs are now easily observed on the fused posterior segments. After 3-4 days in the 3rd instar, the moult to the 4th and final instar takes place.



3rd instar caterpillar, length: 12mm, resting for the moult to next instar.

The 4th instar caterpillar is dark brown in color, with pale brown lateral patches and very wrinkled body surface. Both yellowish green and red forms now have the same appearance in this final instar. The prothoracic shield is initially purplish in color in the early hours of the moult, but turning black soon after.


Three shots of the moutling event from the 3rd to the 4th instar,
ending with the new 4th instar eating its old skin.



Prothoracc shield of the 4th instar caterpilar, initially purple (top) and turning black hours later (bottom)

4th instar caterpillar, length: 12.5mm

The 4th instar lasts for 4-6 days and the body reaches a length of about 21-23mm. Nearing the end of this instar, the caterpillar ceases feeding, and its body shrinks in length. Soon it comes to rest on a spot on the surface of a leaf or a stem, and begins the pre-pupatory phase of its life cycle.


4th instar caterpillar, late in this stage, 21mm

A sequence of shots showing the eversion of the tentacular organs.

The pre-pupatory caterpillar prepares for pupation by spinning a silk pad to which it attaches itself via claspers at the posterior end. Even during this pre-pupal stage, color changes continue to take place with silver replacing the pale brown coloration during the 1.5-2 days of the pre-pupatory period.

A pupation sequence for a Green Imperial caterpillar.

Finally after 16-18 days of larval growth, pupation takes place. The pupa is held firmly via its cremaster to the silk pad on the stem or leaf surface. It is 15-16mm in length, brown to reddish brown in base color with large pale green patches. The pupa was observed to react to an external disturbance by jerking up and down.


Two views of a fresh pupa of Green Imperial

Eleven 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 (female)


A newly eclosed male Green Imperial drying its wings on its pupal case.


A newly eclosed male Green Imperial.


A female Green Imperial

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 Mark Wong, Tan Ben Jin, Khew SK and Horace Tan

Butterfly of the Month - April 2009

Butterfly of the Month - April 2009

The Chequered Lancer (Plastingia naga)

This is the first time that we are featuring a species of the family Hesperiidae as our Butterfly of the Month. The Hesperiidae, or commonly referred to as Skippers, are fast-flying butterflies. An earlier blog article - The Speedsters of the Butterfly World - the Skippers, introduced this family of butterflies, which occupy a position between true butterflies, and true moths.

Skippers are generally drab coloured and not considered the most attractive of butterflies. However, they are significant in their number of species and due to their relatively understudied status, more species remain to be discovered.

The Chequered Lancer (Plastingia naga) is one of two species representing the genus Plastingia in South-east Asia. It is a small butterfly, usually not exceeding 35mm wingspan. The upperside is dark brown with whitish yellow hyaline spots and yellow-orange streaks at the wing bases. The hindwing bears a pale yellow inter-neural streaks. The underside markings are unique in featuring black veins with rectangular spots on a white background, giving the butterfly a chequered appearance.

The species is fast-flying, and is on the wing from early morning to noon, and prefers to rest in the shady forest understorey for most part of the rest of the day. When disturbed, the Chequered Lancer takes off at high speeds, but often comes back to a few favourite perches to rest with its wings folded upright.

The Chequered Lancer has an interesting scientific name, naga. In Southeast Asian folklore, naga refers to a serpentine creature that reportedly inhabits the Mekong River in Cambodia and Thailand. Revered as a Buddhist religious symbol, the Naga has a body like that of an anaconda and the head of a dragon, and legends say that it can spit great red balls of fire into the sky.

A Chequered Lancer strikes an unusual pose showing the markings on the forewings only

How this species came to be named after a serpent is curious, and would be an interesting subject for trivia research into the names of butterflies. Perhaps the black-and-white chequer-board appearance is reminescent of the scales of the dragon's body?

The species is moderately common in shady habitats where its preferred host plant, the Fishtail Palm (Caryota mitis) is found. It is found in urban parks as well as the forested areas of the nature reserves in Singapore. Usually found singly, individuals observed tended to fly around and stop on the top surfaces of leaves in the vicinity of its host plant. Photographing them can be quite challenging in the low light situations but occasionally, one will encounter a cooperative Chequered Lancer that will stay still for a few photogenic shots.

A Chequered Lancer perches on a leaf of its host plant. Note the extended palpi in this individual

Like many species of the Hesperiidae, the Chequered Lancer is sensitive to the camera's flash at times, and may 'jump' when the flash goes off. However, once it gets used to the flash, it will stay quite still for subsequent shots.

The caterpillar behaves like many of the Hesperiidae, forming leaf shelters within which it stays 'protected' and moves out to feed on other parts of the leaf. After reaching the final instar, the caterpillar also pupates in its leaf shelter.

A Chequered Lancer's 'baby photo' - a final instar caterpillar with its leaf shelter opened to expose the resident

Males and females are generally similar in appearance, though the females tend to be larger in size, darker and with fewer hyaline spots on the wings.

Text by Khew SK : Photos by James Chia, Chan SC, Tan BJ, Mark Wong & Khew SK

Life History of the Metallic Caerulean

Life History of the Metallic Caerulean (Jamides alecto ageladas)

Butterfly Biodata:
Genus: Jamides Hübner , 1819
Species: alecto C. Felder, 1860
Sub-species: ageladas Fruhstorfer, 1915
Wingspan of Adult Butterfly: 35mm
Caterpillar Local Host Plants: Nicolaia elatior (Zingiberaceae, common name: Torch Ginger), Saraca cauliflora (Leguminosae, common name: Yellow Saraca)

Physical Description of Adult Butterfly:
The Metallic Caerulean is described as the largest species in the elpis subgroup, which is characterized by the post-discal band on the forewing beneath being completely dislocated at vein 3. The male of the species has a black diffuse border on the forewing, expanding to about 1mm at the apex and a series of black marginal spots on the hindwing. The female has the forewing border extending narrowly along the costa to the base. The Metallic Caerulean has bright metallic blue uppersides, and grey ground colour on the undersides with the usual white banding. On the hindwing, there is a black centred orange-crowned eyespot at the tornal area, with some additional submarginal orange markings along veins 1b and 4. There is a white-tipped filamentous tail at vein 2 of the hindwing.


A Metallic Caerulean perching on a flower.


Another Metallic Caerulean perching on a leaf blade.


A mating pair of Metallic Caerulean

Field Observations of Butterfly Behaviour:
This species was listed as being extant by pioneer researchers, but has not been seen in recent years until a colony was sighted and identified in the second half of 2008 thriving in the vicinity of a cluster of Torch Ginger plants by ButterflyCircle members. The adults have a rather quick but erratic flight, and for most of the day, are active and fly in a small area encircling the host plants. Males tend to stay higher up and chase each other in the bright sunshine. Very often both sexes stop to rest in the shade on the uppersides of leaves and demonstrates the movement of the hindwings and tails in the usual Lycaenid fashion. The male has also been found to puddle on bird droppings.

Early Stages:

The local host plant, Nicolaia elatior (Torch Ginger) is a herbaceous perennial plant and grows in large clumps up to about 6m tall. The elongated leaves occur in two alternate rows above the stem. It has showy and pinecone-shaped flower heads, each about 7-10cm long, subtended by large crimson or pink bracts and seated on a long stalk. Various parts of the Torch Ginger are known to have folk medicinal uses.


Torch Ginger: flower (left) and tall clump (right).


A mother Metallic Caerulean laying her eggs on a Torch Ginger flower.

Following the recent discovery of Saraca cauliflora being utilized by two other member species of the elpis subgroup, a successful attempt was made to breed Metallic Caerulean on the Saraca flowers. This establishes the possibility that Saraca cauliflora is an alternate host plant in the wild. The life history recorded and reported in this article is based on two Metallic Caerulean specimens being bred on the Saraca flowers throughout their larval phase.


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

Eggs of Metallic Caerulean are laid singly on an inflorescence of Torch Ginger, typically on the pinecone-like scales above the waxy bract. However due to the large size of the inflorescence, it is not uncommon to find several eggs on one single inflorescence. The egg is disc-like (about 0.8mm in diameter) with a depressed micropylar, and light green in colour. The surface is covered with a reticulated pattern of intersecting ridges, coarse on the rim, but very finely sculptured on the top flat face.


Two views of an egg of the Metallic Caerulean, diameter is about 0.8mm

The collected eggs took two days to hatch. The young caterpillar emerges after nibbling away sufficiently large portion of the egg shell. Measured at a length of about 1.2mm, its pale yellow body is cylindrical in shape, sporting long fine setae (hairs) and a dark head capsule. One can just barely make out the dark brown prothoracic shield which lies immediately behind the head.


A newly hatched caterpillar of the Metallic Caerulean, length: 1.2mm

The newly hatched grazes on the surface of flower petals or bores into a flower bud for the goodies within. Later instar caterpillars also eat the pedicel of the flowers. As it feeds and grows, it gradually takes on a pale red to pinkish tinge.


1st instar caterpillars; Lengths: 2mm (bottom); 2.5mm (top)

After about 2-3 days of growth and reaching a length of about 2.5 to 3mm, the caterpillar moults to the next instar. The 2nd instar caterpillar has a yellowish brown base color, and reddish brown markings running dorsally and laterally. The body surface appears to be covered with tiny black spots. There are still fine setae but these are now much shorter in proportion compared to those in 1st instar. The prothoracic shield is still dark brown in colour.


Two views of 2nd instar caterpillar, lengths: 3mm (top); 4mm (bottom).

The 2nd instar caterpillar reaches a length of about 5mm, and after about 2-3 days in this stage, it moults again. The 3rd instar caterpillar has proportionately shorter but still numerous body setae. There are dorsal and lateral markings, in light reddish brown, running along body axis. The most prominent change is in the color of the prothoracic shield to the body base color of yellowish brown, and also in the color of head capsule to yellowish brown. The dorsal nectary organ (on the 7th abdominal segment) is present but not marked prominently with any colored rings or markings. The tentacular organ is also observable at this stage.


A Metallic Caerulean caterpillar newly moulted to the 3rd instar.
Note the discarded larval skin and head capsule.


3rd instar caterpillar, length: 5mm (top); 7mm

The 3rd instar takes 2.5-3 days to complete with the body length reaching about 7.5-8mm. The 4th (and final) instar caterpillar is similar in appearance to the 3rd instar caterpillar. Overall, the caterpillar appears to be more yellowish in this instar. The body setae are now much shorter, and the prothoracic shield is paler than the body base color.

A Metallic Caerulean caterpillar seen in the end stage of its moult to the 4th instar.


4th instar caterpillar, early in this stage, length: 8mm


4th (final) instar caterpillar, late in this stage. Lengths: 12mm (top), 14mm (bottom).

After 5-6 days of growth and reaching a maximum length of around 14mm in the final instar, the body of the caterpillar gradually shrinks, and decolorizes to a very pale yellow coloration. Both bred specimens chose to enter their pre-pupatory phase on the surface of leaves provided. 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 a pre-pupa of the Metallic Caerulean,

Pupation takes place after one day of the pre-pupal stage. The pupa has the typical lycaenid shape. It is pale yellowish and decorated lightly with a few brown and black specks. The pupa has a length of about 9.5mm.


Two views of a fresh pupa of the Metallic Caerulean.

Six days later, the pupa becomes darkened in color signaling the imminent emergence of the adult. The markings on the upperside of the forewing become visible through the pupal skin, and it is now possible to tell the gender of the soon-to-emerge adult. The next day the adult butterfly emerges from the mature pupa.


Mature pupae: Female (top); Male (bottom). Note the difference in the extent of the
bluish patches in the wing pads.


A newly eclosed female Metallic Caerulean


A newly eclosed Metallic Caerulean male.

References:

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

Text by Horace Tan, Photos by Henry Koh, Anthony Wong, Mark Wong, Sunny Chir, Khew SK and Horace Tan