17 March 2012

Life History of the Common Lascar

Life History of the Common Lascar (Pantoporia hordonia hordonia)

Butterfly Biodata:
Genus: Pantoporia
Hübner, 1819
Species: hordonia Stoll, 1790
Subspecies: hordonia
Stoll, 1790
Wingspan of Adult Butterfly: 40-50mm
Caterpillar Local Host Plants:
Archidendron clypearia (Leguminosae, Mimosoideae), Parkia speciosa (Leguminosae, Mimosoideae, common name: Petai)

A Common Lascar displaying its wing underside.

A Common Lascar puddling on damp ground in the nature reserve.

Physical Description of Adult Butterfly:
Above, the wings are dark brown to black with orange markings. On the forewing, there is a broad orange cell streak with two small indentations. Post-discal spots in spaces 2 and 3 are in echelon. The orange submarginal line on the forewing  has a thinner grey fascia lying on the inner side. The hindwing has a subbasal streak passing through base of cell, and a basal streak passing along costa. The dorsum of the thorax has a small orange   band aligned with the forewing cell streaks. Underneath, the wings have pale orange markings corresponding to those on the upperside, but generally larger. These markings are set against a background marbled in pale brown to dark brown paterns with intricate details.

Field Observations of Butterfly Behaviour:  
This species is moderately common in Singapore and its distribution is restricted to the Central Catchment and Bukit Timah nature reserves. The adults are weak flyers  but are rather alert  and skittish, and would quickly ascend to the tree top when alarmed.  The adults have been sighted visiting flowers and puddling on wet ground, and would typically open their wings fully when perching.

Early Stages:
Local host plant #1: Parkia speciosa.
The local host plants, Parkia speciosa and Archidendron clypearia, are common at several locations within the local nature reserves. The caterpillars of the Common Lascar feed on the (compound) leaves of these two  host plants. Although the caterpillar has no qualm with  feeding on green leaflets once in a while,  its diet consists mainly of these leaflets in the withered state. Such leaflets are created after the caterpillar cuts  the petiole or rachis of a compound leaf, thus depriving the detached part of water and nutrient supplies. The detached part stays on the host plant with the aid of  silk threads spun by the caterpillar while it works intermittently to cut the petiole/rachis.

A Petai plant with one compound leaf cut by a Common Lascar caterpillar.

Local host plant #2: Archidendron clypearia.

Between feeding, the caterpillar seeks safety and concealment among the leaflets in the drooping part of the cut compound leaf. To  avoid detection by a prey, Its  movement on the rachis is typically slow, jerky and stealthly.  

Common Lascar: eating withered leaflets, movement and concealment among drying leaflets.

A female Common Lascar ovipositing an egg on a leaflet of the Petai plant.

The eggs of the Common Lascar are laid singly on either surface of a  leaflet of the host plant. The eggs are somewhat globular in shape, with surface marked with hexagonal pits and bearing spines at pit corners, giving them the appearance of minute sea-urchins. The micropylar sits atop. Freshly laid eggs are pale green in colour, and would turn yellowish   when maturing. Each egg has a diameter of about 0.8mm, and a height of about 0.9mm.

Two views of an egg of the Common Lascar laid on the Petai plant.

Two views of a mature egg of the Common Lascar. Note the visiable head capsule of the caterpillar.

The egg takes about 3-4 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 is about 2mm in length. The pale green  body is cylindrical in shape and is covered with many small tubercles and short setae. The head capsule is pale brown in color.

A newly hatched caterpillar half way through eating its egg shell, length: 2mm.

A 1st instar caterpillar hark at work at cutting the rachis of a Petai leaf, length: 2.8mm.

As the caterpillar grows, the body assumes a green to dark green undertone. Four pairs of subdorsal tubercles, found on the 2nd and 3rd thoracic segments, 2nd and 8th abdominal segments, are noticeable upon close scrutiny.  After reaching about 4.0mm in 4-6 days, the caterpillar moults to the 2nd instar.

Two views of a  1st instar caterpillar, length: 2.8mm.

The body of the 2nd instar caterpillar is pale  brownish with a green undertone.  The head is pale brown.  The  surface of both the body and the head is covered with numerous tiny whitish tubercles bearing short setae. This instar lasts about 5-7 days with the body length reaching about 7mm.

Two views of a 2nd instar caterpillar, early in tthis stage, length: 4mm.

Two views of a 2nd instar caterpillar, later in tthis stage, length: 5.6mm.

The 3rd instar caterpillar could occur in two colour forms: green form or brown form  where the body and the head are  pale green or brown respectively.  A long dorsal saddle, which runs from the dorsum of the 2nd abdominal segment and tapers to a narrow dorsal band at the posterior end, begins to take shape towards the end of this instar.  At the same time, faint lateral oblique stripes become noticeable on 2nd, 3rd and 4th abdominal segments. The subdorsal tubercles on 2nd and 3rd thoracic segments, 2nd and 8th abdominal segments are still short but more  pointed than in the 2nd instar.  A pale brown or whitish band runs sub-spiracularly along the side of the abdodmen. This instar takes about 5-7 days to complete with body length reaching about 10mm.

Two views of a 3rd instar caterpillar, early in this stage, length: 6.8mm

Two views of a 3rd instar caterpillar, late in this stage, brown form,  length: 9.8mm.

Two views of a 3rd instar caterpillar, late in this stage, green form,  length: 9.5mm.

The 4th instar caterpillar resembles the 3rd instar caterpillar closely with the same colour forms. In some specimens, one or more of the lateral oblique stripes on the 2nd, 3rd and 4th abdominal segments are darkened and contrast strongly against the body base colour. The 4 pairs of subdorsal spines, though still  diminished in length, are now more prominent in this instar. The long dorsal saddle become more prominent as it appears in lighter shade than the rest of the body.  This instar lasts 6-8 days with body length reaching about 14mm.

Two views of a 4th instar caterpillar, green form, length: 13.8mm.

Two views of a 4th instar caterpillar, brown form, length: 12.5mm.

The 5th instar caterpillar resembles the 4th instar closely.  A general and observable  trend is the slight but noticeable increase in length in the 4 pairs of subdorsal spiones. The long dorsal saddle also gains greater prominence through greater contrast in its colour against the rest of body, and that its front and rear boundary are typically highlighted with dark borders. 

Two views of a 5th instar caterpillar, early in this stage, length: 13mm.

Two views of a 5th instar caterpillar, later in this stage, length: 21mm.

Two views of a 5th instar caterpillar, green form, length: 23mm.

Two views of a 5th instar caterpillar, brown form, length: 23mm.

The 5th instar lasts for about 7-9 days, and the body length reaches up to 22-23mm. On the last day, the color of the body decolorises slightly to a pale shade of brown or green. The caterpillar ceases feeding and stations itself at the underside of the rachis or the mid rib within the cut and withered part of the leaf.  At this pupation site, the caterpillar spins a silk mound  from which it soon hangs vertically to take on the pre-pupatory pose.

The pre-pupa  and the fresh pupa of a brown form  Common Lascar caterpillar.

The pre-pupa and the fresh pupa of a green form Common Lascar caterpillar.

The pupa suspends itself via a cremastral attachment to the silk mound with no supporting silk girdle. Depending on the colour form assumed by the final instar caterpiollar, the fresh pupa could be either brownish or greenish.  The thorax and anterior part of the abdomen are broad, and  the wing cases are dilated laterally. The dorsum of the thorax is raised and angular. Several silvery spots adorn the dorsum of the mesothorax, metathorax and first abdominal segment. The head is bluntly cleft at its front edge with small pointed lateral vertices. Length of pupae: 10-13mm.

Three views of a pupa of the Common Lascar.

After about 5 days of development, the pupal turns dark as the development within the pupal case comes to an end. The orange markings on the forewing upperside become discernible through the pupal skin. The following day, the adult butterfly emerges from the pupal case.

Three views of a mature pupa of the Common Lascar.

A Common Lascar emerges from its pupal case.

A newly eclosed Common Lascar.

  • 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 Federick Ho, Khew SK and Horace Tan