Life History of the Common Palmfly

Life History of the Common Palmfly (Elymnias hypermnestra agina)

Butterfly Biodata:
Genus: Elymnias Hübner, 1818
Species: hypermnestra Linnaeus, 1763
Subspecies: agina Fruhstorfer, 1902
Wingspan of Adult Butterfly: 70mm
Caterpillar Local Host Plants: Ptychosperma macarthurii (Arecaceae, common name: MacArthur Palm), Cocos nucifera (Arecaceae, common name: Coconut), Dypsis lutescens (Arecaceae, common name: Yellow Cane Palm), Caryota rumphiana (Arecaceae, common name: Fish Tail Palm).


A Common Palmfly perching on a cluster of flowers.

Physical Description of Adult Butterfly:
Termens of both wings are prominently scalloped. The hindwing is more strongly toothed at vein 4. Above, the wings are dark brown. On the forewing, there is a series of pale bluish submarginal spots, becoming larger in subapical area and then smaller again along the costal border. In the male, the subapical spots are closer to the apex than in the female. The hindwing is reddish brown with rather pale postdiscal spots. Underneath, the wings are strongly mottled brown. At the apex of the forewing, there is a `thumb-print' (a triangular area in a lighter shade) of varying prominence among specimens. A white spot can be found in the centre of the costa on the hindwing, but this can be absent or inconspicuous in certain specimens.


A Common Palmfly perching on a blade of palm frond.


A Common Palmfly found napping on the stem of a tree.

Field Observations of Butterfly Behaviour: The Common Palmfly is the most widespread species of its genus in the Indo-Australian region. Locally, it is also a rather common species with widespread occurrence across multiple habitats. Typically the adults are shade-loving, and usually sighted flying along the edge of vegetated area and in the vicinity of a clump of palm trees. The adults have the habit of puddling and visiting flowers for mineral and energy intakes.


A newly eclosed Common Palmfly


A Common Palmfly visiting flowers.

Early Stages:
The early stages of the Common Palmfly is polyphagous and feed on the leaves of a number of host plants in the Arecaceae (Palmae) family. Thus far, four of them are fully identified and listed above.

Host plant: MacArthur Palm.
A mating pair of the Common Palmfly (female on the left).

The eggs of the Common Palmfly are laid singly on a leaf blade of the host palm tree, typically on the underside. Each egg is almost spherical with a slightly protruding top (diameter: 1.3-1.4mm). The egg is initially white when freshly hatched but turns yellow on the following day. The surface is faintly and irregularly reticulated.

Two views of an egg of the Common Palmfly.


Two views of a one-day old egg of the Common Palmfly.


Two views of a mature egg of the Common Palmfly. Note the clearly visible head and body setae of the caterpillar.

The egg takes about 4 days to hatch. The young caterpillar emerges by eating away part of the egg shell. The rest of the egg shell becomes the first meal for the newly hatched, which has a length of about 3mm. Its cylindrical body is pale yellowish. The large head capsule is black in color and has three pairs of prominent protuberances lining the perimeter with the apical pair being the largest and longest. Each protuberance ends with a thick setae bearing a transparent droplet at its tip. Rows of fine setae, also bearing terminal droplets, run along the length of the body dorso-laterally and laterally. A pair of long pale-yellow processes occur at the posterior end of the body, each of which ends with a drop-bearing black setae.

Two views of a newly hatched caterpillar near the empty egg shell, length: 3mm.

Once the newly hatched moves on to feed on the young leaves, its body starts to take on a green undertone. Several contrasting bands, yellow in color and of varying widths, adorn the body surface dorsally and laterally. This instar lasts 3 days with the length reaching up to 6mm.

Two views of 1st instar caterpillar, late in this stage, length:5.5mm.

A Common Palmfly caterpillar just before its moult to the 2nd instar (top), and soon after the moult (bottom).

The body of the 2nd instar caterpillar is similarly marked as in the late 1st instar. The most obvious change is in the head capsule where the three pairs of protuberances becomes longer and the setae they bear shorter. The apical pair also takes on a few short side branches. Small pale yellow patches appear laterally and apically on the head capsule. The pair of anal processes are longer proportionately and mostly black in coloration. Numerous short fine setae cover the body surface. Of the several yellowish bands running lengthwise, the dorso-lateral pair running up to the upperside of the anal processes becomes the most prominent of all. This instar lasts about 4 days with the body length reaching up to 10.5mm before the moult to the 3rd instar.

Head capsules: 1st instar (left) and 2nd instar (right).


Two views of a 2nd instar caterpillar, length: 8.5mm

The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar with the only obvious change being in the appearance of the head capsule. Now the ground colour of the head capsule is yellow except for two lateral reddish brown patches running vertically from the apical pair of protuberances, which are also reddish brown in color. The other protuberances turn yellowish with their short terminal setae still brown to black in color. This instar takes about 4 days to complete with body length reaching about 16-17mm.

A Common Palmfly caterpillar just before its moult to the 3rd instar (top), and soon after the moult (bottom).


Two views of a 3rd instar caterpillar, length: 12.5mm.

Retaining very much the same body features from the earlier two instars, the 4th instar caterpillar distinguishes itself in having proportionally longer apical protuberances on the head capsule and the anal processes being mostly yellowish to pinkish in coloration. This instar lasts 3.5 to 4 days with the body length reaching about 26mm.

A Common Palmfly caterpillar just before its moult to the 4th instar (top), and soon after the moult (bottom).


Head capsules: 3rd instar (left) and 4th instar (right).


Two views of a 4th instar caterpillar, length: 26mm.

The 5th and final instar brings about another change in the appearance of the head capsule. Now white patches cover the frontal and middle area, stretching up into the apical protuberances. The long and slender anal processes are mostly pinkish in coloration.

A Common Palmfly caterpillar just before its moult to the 5th instar (top), and soon after the moult (bottom).


Two views of a 5th instar caterpillar, length: 40mm.


Head capsule of the 5th instar caterpillar.

The 5th instar lasts for 3.5-4 days, and the body length reaches up to 40mm. On the last day, the caterpillar ceases feeding, its body becomes shortened but with essentially no change in body color. It wanders around in search of a pupation site. Typically it comes to a halt on the underside of leaf blade where the caterpillar spins a silk pad to which it attaches its graspers and then rests in a head-down posture.

Pre-pupatory larva at three time points. Left: early stage; middle: mid-way, right: late stage with the onset of pupation only minutes away.

The pupation event of a Common Palmfly caterpillar.

Pupation takes place 1 day after the caterpillar assumes the haed-down posture. The green pupa has yellowish strips running on the dorsum of the thorax, dorso-laterally and laterally on the abdomen and the leading edges of the wing case. These yellow strips are outlined in pink. The pupa also has a pair of short cephalic horns, and its dorsum is angled at the thorax. Length of pupae: 22-23mm.

Two views of a pupa of the Common Palmfly.

Two views of a mature pupa of the Common Palmfly.
After about 6-6.5 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The pupa is mostly black at this point. The following day, the adult butterfly emerges from the pupal case. It then perches on the pupal case or nearby to expand and dry its wings before taking its first flight.

A newly eclosed Common Palmfly drying its wings on its pupal case.

A newly eclosed Common Palmfly.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
• A Photographic Monograph on Hong Kong Butterflies, Volume 1, Hong Kong Lepidopterists' Society.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

Text by Horace Tan, Photos by Anthony Wong, Federick Ho and Horace Tan

Butterfly of the Month - November 2010

Butterfly of the Month - November 2010
Tawny Palmfly (Elymnias panthera panthera)

The winds have shifted and now the prevailing winds are coming from a North-Easterly direction, usually bringing heavy rains to many parts of South-East Asia. The monsoon months traditionally brings closure to many activities in nature areas in Malaysia, where the national parks and nature reserves are closed for the safety of visitors. I recall being shown the flood level at Endau-Rompin National Park in Malaysia, where the debris from a recent flood clearly indicated the water line before the water receded. Nothing out of the ordinary, except that the debris line was about two-thirds up a line of trees that was about 15m high!

The 11th month of the year, November always brings happy anticipation of the Christmas holiday season. Indeed, cheery and glittering decorations are already up in many shopping malls in Singapore. In multi-cultural Singapore, November 2010 also saw the celebration of Deepavali and Hari Raya Haji by the Hindu and Muslim communities respectively.

This month, we feature a relatively 'plain-Jane' butterfly, the Tawny Palmfly (Elymnias panthera panthera). The English common name of the butterfly is rather curious, as "tawny" often refers to a "warm sandy colour" which the species displays very little of. Perhaps the pale buff submarginal border on the upperside of the hindwing is distinctive enough to give the butterfly a 'tawny' descriptor.

Another unique feature of this species is its scientific name. It is one of only a handful of butterfly species to share the name of mammals and in this case, a specific genus of the big cats, Panthera. A rather interesting reference, since the butterfly bears no resemblance in any way to the famous carnivorous and predatory cats.

The Tawny Palmfly is a forest denizen, where it skulks close to the forest floor in well-shaded localities. It is usually very skittish and flies off the moment it senses any movement towards it. The species is best observed when feeding on the ripened fruits of the Singapore Rhododendron (Melastoma malabathricum) - when it is less skittish and allows an observer to move in closer to it.

It doesn't fly rapidly but displays an erratic flight when flying around, searching for food sources or moving around its preferred habitats. Very often, it stops and perches on the upper surfaces of leaves with its wings folded upright. In the field, we have, thus far, not encountered an individual sunbathing with its wings opened flat before.

The Tawny Palmfly is dark brown above and the hindwing has a pale buff border bearing a series of white-centred black submarginal spots. The underside bears the usual reddish-brown striations of the genus Elymnias (collectively called the Palmflies) which helps to camouflage the butterfly when settled amongst the forest litter.

The female of this species makes an interesting audible clicking sound with its hindwings when it flutters about its host plant laying eggs. The caterpillar of this species feeds on a variety of palms found in the forests.

Although it is a species that is primarily found in forested areas, and in particular, in habitats where various species of Palmae grow, it has also been observed with regularity at urban parks and gardens as well. Sometimes it flies in the company of its closely related species, the Common Palmfly.

Text by Khew SK : Photos by James Chia, Chng CK, Federick Ho, Khew SK, Koh Cher Hern, Loke PF, Bobby Mun, Ellen Tan & Anthony Wong

Life History of the Plain Tiger

Life History of the Plain Tiger (Danaus chrysippus chrysippus)

Butterfly Biodata:
Genus: Danaus Kluk, 1802
Species: chrysippus Linnaeus, 1758
Subspecies: chrysippus Linnaeus, 1758
Wingspan of Adult Butterfly: 65mm
Caterpillar Local Host Plant: Calotropis gigantea (Asclepiadaceae, common name: Giant Milkweed), Asclepias curassavica (Asclepiadaceae, common name: Blood Flower).


A Plain Tiger found visiting a flower.

Physical Description of Adult Butterfly:
Above, the forewings are orangey brown with a series of white spots in a broad black apical border. The hindwings have a narrow dark border and a few black spots featured at both the cell edge and end-cell. In form chrysippus, the hindwings are orangey brown, but in form alcippoides, the hindwings are almost white throughout. The male has a subtornal brand on the hindwing just below vein 3. Underneath, the wings are similarly marked as per the upperside but with apical border orangey brown on the forewing, and wing margins marked with a series of prominent and white marginal spots.


A Plain Tiger form chrysippus sunbathing on a fern frond.


A Plain Tiger form alcippoides displaying its upperside.


Plain Tiger adults imbibing fluid/sap from parts of two different plants.

Field Observations of Butterfly Behaviour:
Both forms of the Plain Tiger can be found in Singapore with form alcippoides being the more common of the two. This species is typically found where its host plants are cultivated. Such locations include HortPark, butterfly trails, butterfly gardens in schools and housing estates and even certain park connectors. The adults typically visits flowers in the vicinity of its host plant and has a fondness for sap exuded by Crotalaria spp.


A Plain Tiger perching on a fern frond in a closed-wing pose.


A newly eclosed Plain Tiger

Early Stages:
Caterpillars of Plain Tiger feed on leaves of its host plants, Giant Milkweed and Blood Flower, both of the Asclepiadaceae family (the Milkweed family).

Local host plants for the Plain Tiger: Giant Milkweed (left) and Blood Flower (right).

A mating pair of Plain Tiger.

The eggs of the Plain Tiger are laid singly on the leaf of the host plant, typically on the underside. The milky white egg is shaped somewhat like a bullet-head (diameter: 0.95mm, height: 1.3mm). The egg surface is ribbed with ridges running longitudinally. The micropyle sits atop.

A mother Plain Tiger ovipositing on its host plant.

Two views of an egg of the Plain Tiger.

The egg takes about 2.5-3 days to hatch. The young caterpillar emerges by eating away part of the egg shell. The rest of the egg shell becomes the first meal for the newly hatched, which has a length of about 2.2mm. Its cylindrical body is mostly white with a yellowish undertone, and has a fair number of short fine setae. The large head capsule is black in color and there is a small black patch at the posterior end. A pair of short sub-dorsal protuberances can be found on each of the following four segments: 1st and 2nd thoracic segments, 2nd and 8th abdominal segments. Of these, the prothoracic pair is black in color and the remaining pairs in orangey brown. The thoracic legs and prolegs are all black in color.

Two views of a newly hatched caterpillarl, length: 2.2mm.

Once the newly hatched moves on to feed on leaf lamina over the next few hours, its body starts to take on a green undertone. The growth is rather rapid with the body length doubling to about 4.5mm in 1.5 day, and after just 1.5 to 2 days from hatching, it moults to the 2nd instar. Towards the final hours of the 1st instar, the last three pairs of protuberances turn dark brown and pairs of oval-shaped yellow spots appear on the dorsum from the 2nd thoracic segment to the 8th abdominal segment.

Two views of a 1st instar caterpillar, length: 3.5mm.


Two views of a 1st instar caterpillar, late in this stage, length:4.3mm.

The body of the 2nd instar caterpillar is whitish in ground color. One obvious change is the lengthening of those black protuberances on the 2nd thoracic segment, 2nd and 8th abdominal segments The pair of protuberances on the 1st thoracic segment remains subdued in size. A diffused yellow band runs sub-spiracularly. The subdorsal paired yellow spots are embedded in dark patches which extend laterally to the subspiracular yellow band. Noteworthy is that there is only one (rather than two) elongated yellow dorsal spot on the 9th abdominal segment. The black head capsule now has a triangular white patch on the frons and a prominent white arch. This instar lasts only 1 to 1.5 days with the body length reaching 9mm before the moult to the 3rd instar.

Two views of a 2nd instar caterpillar, early in this stage, length: 5.7mm


Two views of a 2nd instar caterpillar, late in this stage, length: 8.5mm

The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar, One obvious change is in the three pairs of processes which are proportionately longer. The head capsule also has an outer white arch at the rear periphery. This instar takes about 1-1.5 days to complete with body length reaching about 12mm.

3rd instar caterpillar, newly moulted, length: 8.5mm


3rd instar caterpillar, late in this stage, length: 12mm.

Retaining very much the same body features from the previous instar, the 4th instar caterpillar distinguishes itself in having proportionately longer processes, with the mesothoracic pair the longest and having a strong tendency to flex forward. This instar lasts 2 days with the body length reaching about 21mm.


Two views of a 4th instar caterpillar, late in this stage, length: 12mm.


Two views of a 4th instar caterpillar, late in this stage, length: 16mm.


4th instar caterpillar, late in this stage, length: 21mm.

A group of Plain Tiger caterpillars defoliating a Blood Flower plant.

The 5th and final instar appears similar to the previous two instars but again with proportionately longer and filamentous processes, particularly so for the mesothoracic pair. All six processes now have a crimson coloration at the basal portion.

Two views of a 5th instar caterpillar, early in this stage, length: 26mm.


Two views of a 5th instar caterpillar, length: 34mm.


Two views of a 5th instar caterpillar, late in this stage, length: 39mm.

The 5th instar lasts for 2-3 days, and the body length reaches up to 42mm. On the last day, the caterpillar ceases feeding, and its body becomes shortened and decolorized, most notably in the yellow and crimson coloration. It wanders around in search of a pupation site. Typically it comes to a halt on a branch/stem or a leaf underside, where the caterpillar spins a silk pad from which it soon hangs vertically to take on the pre-pupatory pose.

A pre-pupatory larva of the Plain Tiger.

Pupation takes place about 0.75 days after the caterpillar assumes the hanging posture. The barrel-shaped pupa suspends itself from the silk pad with no supporting silk girdle. The pupa could be green, pink even white in coloration. It has a median transverse line marked with a series of black spots and an outer series of yellow spots. Length of pupae: 19-20mm.

Two views of a pupa of the Plain Tiger.

Two views of a mature pupa of the Plain Tiger.

After about 5 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The prominent white spots on the forewing upperside also become discernible. The following day, the adult butterfly emerges from the pupal case.

A newly eclosed Plain Tiger drying its wings on its pupal case.

References:

• 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 Liyana Zolpakar, Tan Ke-Yang, Mark Wong, Anthony Wong and Horace Tan