08 June 2008

Life History of the Malay Lacewing

Life History of the Malay Lacewing (Cethosia hypsea hypsina)
An updated version of the life history of the Malay Lacewing can be viewed by clicking this link.


Butterfly Biodata:
Genus: Cethosia Fabricius, 1807
Species: hypsea Doubleday, 1847
Subspecies: hypsina C. & R. Felder, 1867
Wingspan of Adult Butterfly: 80mm
Caterpillar Host Plants: Adenia macrophylla var. singaporeana



A Malay Lacewing resting on a perch in the wild.


A male Malay Lacewing visiting flowers of Leea indica.

Physical Description of Adult Butterfly:
Above, the forewings are black with a white subapical band beyond the cell; the basal area is orange-red for the male (with the red confined to the base of the wings) and black for the female (with a yellowish-white patch in mid space 1b). The hindwing upperside is entirely orange-red except for the scalloped black distal border. Underneath, the wings are orange-red with white fasciae and are spotted with black, and the forewing cell has several black-edged, pale blue transverse stripes. The wing borders are dark coloured and deeply indented with lace-like pattern of white markings. One distinguishing feature to separate Malay Lacewing from other Cethosia species is the absence of a white submarginal band on the hindwing underside.

Field Observations of Butterfly Behaviour:
Locally the occurrence of this species is restricted to the forested nature reserves, possibly due to its preferred host plant being found only in such areas. It is not uncommon in the reserves, and adults can be spotted visiting flowers of flowering plants such as Leea indica in forest clearings or alongside trekking trails. At appropriate times, females can also be seen checking out leaves in search of an ovipositing site. More about the adult behaviour can be found in an earlier blog article in the Butterfly of the Month series.


Early Stages:
The local host plant is a member of the Passifloraceae family. Also known as Singapore Adenia, it is a botanical variety of Adenia macrophylla which occurs only in Johor and Singapore. One prominent feature of this tendrillate climber is the pair of spatulate glands at the leaf blade base. This plant is a forest dweller and can be found in the Central Catchment Nature Reserves and Pulau Ubin.


Host plant : Adenia macrophylla var. singaporeana

The eggs of the Malay Lacewing are laid in large clusters on the underside of a youngish or middle-aged leaf, around a stem or a tendril. Each egg is pale yellow, cylindrical and ribbed, taller than broad (1.5mm versus 1mm).


A female Malay Lacewing flying near an ovipositing site.


A cluster of fresh eggs of Malay Lacewing laid on a stem

Each egg takes about 6 days to mature. The young caterpillar pushes its way through the cracked egg shell, and does not bother to eat the empty egg shell. The newly hatched has a cylindrical body in yellowish brown, and an initial body length of about 3mm. The body is covered in a grid of dark tubercles, each with a single long seta. The head is black and there is a pair of short black spines on the first thoracic segment. The young caterpillar either skims the lamina on a young leaf or nibbles away at the tip of a young stem. The Malay Lacewing caterpillars are gregarious throughout all five instars, often eating (leaves and stems) and moulting together in groups.


Eggs in various stages of development, including mature eggs and empty egg shells.


Newly hatched 1st instar caterpillar, length: 3mm


1st instar caterpillar, day 2 in this stage, checking out the spatulate
glands of the Adenia leaf; length: 4mm


As the 1st instar caterpillar grows to a length of 5mm, the body color changes gradually to pinky red, and a faint white saddle mark appears on the 4th abdominal segment. After about 2.5 days in 1st instar, the caterpillar moults to the next instar.


1st instar caterpillar, day 3 in this stage, ready to moult; length: 5mm

The 2nd instar caterpillar has a wine-red body colour, and the rows of tubercles in the 1st instar are replaced by 6 longitudinal rows of dark fine-pointed spines, 3 to each side of the body. The spines in uppermost two rows are the longest. A pair of short and black coronal spine appears on the head. The white saddle is now more prominently marked, and carries black-tipped white spines.
This instar lasts 2.5 days with the body length reaching about 9mm before the next moult.


2nd instar caterpillar, early in this stage, 5.5mm

In the 3rd instar, there is no drastic change in physical appearance except for proportionately longer coronal spines (now about the same length as the height of the head capsule), and the larger and more distinct white saddle mark. This instar takes 3 days to complete with body length reaching about 16mm.


3rd instar caterpillar, early in this stage, length: 9.5mm


3rd instar caterpillar, late in this stage, length: 16mm

The coronal spines in the 4th instar caterpillar are again longer proportionately with the length of each spine about equal to the 1.5x height of the head capsule. The 4th instar lasts about 2-3 days with body length reaching about 24mm.


4th instar caterpillar, early in this stage, length: 16mm


A group of 4th instar caterpillars, with one subgroup ringbarking a young stem.



A group of caterpillars just moulted to 5th instar on the underside of a leaf

The next moult brings the caterpillar to its 5th and final instar. Now the coronal spines are about 2x the height of the head capsule. The upper half of the body is bright wine red, while the lower half is dark red. This phase lasts for 4 days before the caterpillar stops eating, and at this time the body length is 38-40mm.


5th instar caterpillar, early in the stage, 30mm


A group of 5th instar caterpillars sharing an Adenia leaf

Toward the end of 5th instar, the caterpillar moves about restlessly between feeds. Finally the caterpillar finds a spot on the underside of a leaf, stalk or stem to secure itself at the anal end, from which it hangs vertically as a pre-pupa. The pupation site needs not be on the host plant itself. In the wild, Malay Lacewing pupae have been found on other plants several metres from the Adenia host plant.


Left: A pre-pupatory larva of Malay Lacewing
Right: Pupa, newly pupated, still reddish to reddish brown on most parts.


Pupation takes place a day later. The pupa hangs vertically. It has two pairs of pointed white processes at the middle of its body and a number of less prominent dorsolateral processes. A pair of black foliaceous processes adorn the head. Body color is pale brown mottled with white and black patches, and several dorsal spots of bright gold. When disturbed, the body could jerk sideways through the movement of the posterior abdominal segments. Length of pupae: 28-29mm.


Pupa of Malay Lacewing; fresh on left and mature on right

After 7 days of development, the pupa becomes darkened. The next day the adult butterfly emerges to kick-start the next cycle in its lineage.


A newly eclosed Malay Lacewing dryig its wings on the pupal case

In one particular field visit, a newly eclosed adult was observed to mate right next to its empty pupal case. It was apparently the target of the older mate who had been seen flying in and out of the bush earlier.



A newly eclosed Malay Lacewing becomes part of a mating pair

Acknowledgments:

I would like to express my gratitude to Samsuri Ahmad and Ali Ibrahim of NParks, and botanist Joseph Lai for generous assistance in the identification of the host plant (Adenia macrophylla var. singaporeana).

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

01 June 2008

Plus Two makes 284

Re-discovery of two more species of Lycaenidae brings the Singapore Checklist to 284 species.



The recent re-discovery of two more species of Lycaenidae - one from the genus Nacaduba and the other from the genus Manto brings the total number of species in the Singapore Checklist to 284 species.

The Jewel Four-Line Blue (Nacaduba sanaya elioti)

The first species is the Jewel Four-Line Blue (Nacaduba sanaya elioti ). The genus Nacaduba comprise many species which look very similar to each other and are not easy to identify in the field. However, our ButterflyCircle member, Horace Tan, who specialises in the early stages of butterflies, managed to observe this species over a few months and managed to breed the species from egg to adulthood.



The pristine adult specimens were then compared with the reference books and it was discovered that this specimen was not similar to the other species already recorded in the Singapore checklist. This species, obviously belonging to the pavana group (the 4-line Blues) is also without a basal pair of lines in the forewing cell beneath.


A female Jewel Four-Line Blue oviposting on its host plant, and the leaves of the host plant of this species.

After careful investigations and seeking advice from our foreign expert, Prof Konrad Fiedler, a renowned expert in tropical Lycaenidae, it was confirmed that this species is indeed the Jewel Four-Line Blue (Nacaduba sanaya elioti). It is now re-instated into the Singapore Checklist, where it was originally recorded as extant by Corbet & Pendlebury as well as W. A. Fleming.

The Green Imperial (Manto hypoleuca terana)

The second species is the Green Imperial (Manto hypoleuca terana). Described as "rather rare and is more often taken in the forest at low to moderate elevations than on the hill tops", the species has been earlier observed, but only on this opportune occasion where a pristine male was observed with its characteristic green upperside, when the species could finally be positively identified.



This species appears superficially similar to the Grand Imperial (Neocheritra amrita amrita) and the Great Imperial (Jacoona anasuja anasuja). However, the Green Imperial has a wider suffusion of orange on the hindwing below, almost reaching the dorsal margin of the hindwing below, unlike the other two species, particularly in the males. That the post-discal striae reach vein 6 on the hindwings also reaffirms this species identification.




Photographed at the edge of the nature reserves feeding on the flowers of the Yellow Cane Palm (Dypsis lutescens), the fortunate encounter has confirmed the existence of this rare Lycaenid in Singapore, and the species Green Imperial (Manto hypoleuca terana) has been reinstated to the Singapore Butterfly checklist as species # 284.


Text by Khew SK : Photos by Khew SK & Horace Tan

25 May 2008

Life History of the Malayan Bush Brown

Life History of the Malayan Bush Brown (Mycalesis fusca fusca)


Butterfly Biodata:
Genus: Mycalesis Hübner, 1818
Species: fusca C. & R. Felder, 1860
Subspecies: fusca H C. & R. Felder, 1860
Wingspan of Adult Butterfly: 45mm
Caterpillar Local Host Plant: Scleria bancana (Cyperaceae)


Physical Description of Adult Butterfly:
Underside, both wings are yellowish brown in ground colour, with two reddish/orangy brown longitudinal stripes crossing from the upper to lower edges, and a series of moderate to small ringed spots (ocelli) in the submarginal area. The post-discal area of the hindwing carries a reddish brown coloration. Above, the male is brown with obscure post-discal ocelli while the female is pale brown with more distinct post-discal ocelli. The female is typically larger in size.


Field Observations of Butterfly Behaviour:
This species is one of the less common of the Mycalesis genus in Singapore, and thanks to its more striking undersides, it is also one of the more distinctive members of this genus which typically features dull brown adults. Local sighting locations include the Central Catchment Nature Reserve and the Bukit Timah Nature Reserve. Individuals are usually encountered flying alongside forest trails or lurking in shady undergrowth in the vicinity of its host plant. As with other Satyrinae members, the adults fly in an erratic and jerky manner as their wings are closed for a relatively long period during flights.

Early Stages:
The host plant is a member of the Cyperaceae (Sedge) family, a grass-like herb with triangular stems and 3-ranked leaves with sheaths. This plant is rather common in the Catchment Reserves and even along trails in the Southern Ridges.

Host plant: Scleria bancana.

The eggs of the Malayan Bush Brown are laid singly on the grass leaf blade. Each egg is more or less spherical (about 1mm in diameter) and light translucent yellow. It appears to be smooth to the naked eyes, but faintly sculptured with a hexagonal reticulum when viewed with a more extreme close-up camera set-up.

A fresh egg of Malayan Bush Brown

The egg takes 4 days to mature. The young caterpillar pushes its way through the cracked egg shell, and then proceeds to eat up the egg shell almost entirely. It has a spindle-shaped body in light creamy yellow colour, and an initial body length of about 4mm. The body has rugose and ill defined segments. There is a pair of backward-pointing anal projections and a black head with a pair of short and rounded horns on the head. The young caterpillar eats the leaf blade along the edge. Caterpillars of all instars are observed to be sluggish in movement. They tend to rest lengthwise on the underside of a leaf during pauses between feeds.

Mature egg with the head about to break through the shell

Newly hatched 1st instar caterpillar, length: 4mm

The first instar lasts 4 days with the body length increases to about 6mm before the inevitable moult. With the change of instar, the two cephalic on the head become pointed and the two anal projections longer and thus pronounced. The body colour is yellow with a green undertone. The head and body is also roughened by numerous minute tubercles, each with a single seta. Faint longitudinal lines are also distinguishable on the body.

2nd instar caterpillar, early in this stage, 6.5mm

2nd instar caterpillar, late in this stage, length: 10mm

The 2nd instar lasts for 4 days with the body length reaches about 11mm before the next moult. The 3rd instar caterpillar mostly resembles the previous instar except for having longer anal projections and more prominent longitudinal lines on its body. This stage also takes 4 days to complete with body length reaching about 16mm.

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

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

One obvious change in the 4th instar caterpillar is in the head where the "face" area has changed from dark brown to yellowish green while the forward-facing portions of the horns remaining dark brown. The 4th instar lasts about 5 days with body length reaching 22-23mm.

4th instar caterpillar, length: 16mm

The next moult brings the caterpillar to its 5th and final instar. Now the "face" area of the head is pale yellow in colour and decorated with three pairs of curved brown lines. The body is dotted with several prominent black spots, and the longitudinal lines become more striking with alternating and varying shades of brown and green. In a period of 9 days, the body grows at a faster pace to a maximum length of about 40-42mm.

5th instar caterpillar, early in the stage, 30mm

5th instar caterpillar, late in this stage, length: 40mm

Toward the end of 5th instar, the body gradually shrinks in length and becomes paler in colouration. Finally the caterpillar finds a spot on the underside of a leaf blade to secure itself at the anal end. The dormant pre-pupatory pose is complete once it has its body curved up and the head touches part of the body.

Preparatory pupa of Malayan Bush Brown

After one day as a pre-pupa, pupation takes place. The smooth pupa is light woody brown with faint brown markings. It is somewhat angular, with a dorsal keel on the thorax and ridges defining the dorsal wing margins. Length of pupae: 15-16mm.

Fresh pupa of Malayan Bush Brown

After 9 days of development, the pupa becomes darkened in color especially at the wing pads (corresponding to the dark brown uppersides of the forewings). The next day the eclosion event takes place with the adult butterfly emerges to start the next life cycle.

Mature pupa of Malayan Bush Brown

A newly eclosed Malayan Bush Brown

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 Press 1999
Text and Photos by Horace Tan