05 February 2011

Life History of the Harlequin

Life History of the Harlequin (Taxila haquinus haquinus)

Butterfly Biodata:
Genus: Taxila Doubleday, 1847
Species: haquinus Fabricius 1793
haquinus Fabricius 1793
Wingspan of Adult Butterfly: 45mm
Caterpillar Local Host Plants:
Ardisia elliptica (Myrsinaceae).

A female Harlequin on a leaf perch.

Uppersides of a male Harlequin (left) and a female Harlequin (right).

Physical Description of Adult Butterfly:
Above, the male is dark brown except for the sub-apical portion of the forewing which is pale reddish brown; the female is reddish brown, marked with a fair number of black spots and has a sub-apical white band not crossed by dark veins. Underneath, for both sexes, the underside is reddish brown, and marked by a number of silvery-white spots and white-edged black spots. The female has a broader and more prominent white sub-apical patch on the forewing.

Field Observations of Butterfly Behaviour:
The shade-lovng adults are typically found in forested areas in the vicinity of its host plants. They are often seen perching on upper surface of leaves with half-open wings, turning and hopping from one perch to the next. So far, this species was sighted at only one habitat on the main island of Singapore where the unique environment allows the species to thrive. However, the impending re-development of that area threatens to wipe out that colony (More on the effort to save this species can be found in earlier blog articles here and here).

Early Stages:
The host plant, Ardisia elliptica, is a large shrub or small tree. The leaves are simple, alternate, grandulate, obovate and leathery, 8-12 cm long and have nearly invisible nerves. In the wild, the plant grows in tidal swamps and muddy river banks. The immature stages of the Harlequin feed on the relatively young leaves of the host plant, typically on the underside. The first instar caterpillars graze on the leaf surface, and the later instars nibble along the leaf edges. Between feeds, the caterpillars of all instars rests on the leaf underside.

Host plant : Ardisia elliptica

In the wild, the female lays its eggs singly on the surface, usually on the underside, of a leaf of the host plant. However, in an indoor breeding environment, the females have been observed to lay multiple eggs within close proximity of each other. Each egg is pale translucent yellow, somewhat conical in shape with a base diameter of about 0.7mm. The surface is smooth and has a mid-level inconspicuous belt of fine hairs encircling the egg.

Two views of an egg of the Harlequin. Diameter: 0.7mm.

Two views of a mature egg of the Harlequin. Both the mandible and setae are visible through the egg shell.

A newly hatched caterpillar of the Harlequin, length: 2mm.

It takes about 3.5-4 days for the egg to hatch. The young caterpillar consumes part of the egg shell to emerge. With a length of about 1.9-2.0mm, it has a pale greenish and cylindrical body with long setae dorso-laterally and sub-spiracularly. The body color changes to a brighter shade of yellow with a green undertone as it feeds and grows. Conical tubercles, one pair to each body segment, become prominently featured laterally. Each tubercle is furnished with a tuff of setae.

A 1st instar caterpillar showing us the result of its grazing work, length: 2.9mm

The first instar lasts for 3.5-4 days and the body length reaches about 3mm. Prior to the moult to 2nd instar, the body shortens and takes on a pumped up appearance. This shortening routine also occurs prior to each of the subsequent moults.

A late first instar caterpillar, in dormant mode prior to its moult, length: 2.9mm.

A newly moulted 2nd instar caterpillar with the excuvia (shed larval skin) lying nearby.

The body color of the 2nd instar caterpillar is yellow with a greenish undertone. Small reddish patches are seen on the some of the lateral conical tubercles. Overall, the hairy appearance is little changed from the 1st instar. This instar lasts for 3-3.5 days and the caterpillar grows to a length of about 5-5.5mm before the moult to the 3rd instar.

Two views of a second instar caterpillar, early in this stage, length: 2.8mm.

Two views of a 2nd instar caterpillar, length: 4mm.

Two views of a late 2nd instar caterpillar, in dormant mode prior to its moult, length: 4.8mm.

The 3rd instar caterpillar is yellowish green with a much greater emphasis in green. Reddish patches are more prominently featured on the conical tubercles. After 3-3.5 days in this stage with the body length reaching a maximum lenght of about 7.5mm, the caterpillar moults to the penultimate instar.

Two views of a 3rd instar caterpillar, early in this stage, length: 4.5mm.

Two views of a 3rd instar caterpillar, length: 7.5mm

Two views of a 3rd instar caterpillar, in dormant mode prior to its moult, length: 7mm

The 4th instar caterpillar has a reddish patch surrounding each spiracle which is whitish in coloration. The distal end of each conical tubercle is also colored in red. Whitish dashes also appear dorsally and dorso-laterally. resembles the 3rd instar caterpillar but with a much denser set of sub-spiracular setae. The body is mainly green in ground color. Overall, the caterpillar has a more striking appearance than in the previous instar. This instar lasts for 4-4.5 days and the body grows up to a length of about 14mm.

Two views of a a 4th instar caterpillar, early in this stage, length: 9,5mm.

Two views of a 4th instar caterpillar, length: 10.5mm

Two views of a 4th instar caterpillar, late in this stage, length: 12.5mm

The 5th instar caterpillar closely resembles the 4th instar caterpillar except for the appearance of a black spot on the dorsum of each segment from the metathorax to the 7th abdominal segment. All the body setae are dark in coloration except for those occurring sub-spiracularly which are in a contrasting whitish coloration. The body ground color could vary from pale green to pale brown in different individuals.

Two views of a 5th instar caterpillar, length: 19mm

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

The head capsule of a 5th instar caterpillar.

The 5th instar lasts for 5-5.5 days and the body grows up to a length of about 29mm. On the last day of this instar, the caterpillar ceases food intake and its body shrinks in length and decolorises. It then finds a spot on the leaf surface where it spins a silk pad and a silk girdle to secure itself for the upcoming pupation event.

Two views of the pre-pupa of the Harlequin.

After 1-1.5 day of the pre-pupal phase, pupation takes place. The green pupa has a elongated diamond-shaped outline, being broader at mid-body and pointed at the front and rear ends. The body has pale pinkish patches dorso-laterally and laterally, with a number of dark spots, symmetrically spaced on each body segment. Laterally, there are some hairs running along the fringe of the body. Each pupa is 20-22mm in length.

Two views of a pupa of the Harlequin.

6-6.5 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 of a male Harlequin, minutes prior to the eclosion event.

A newly eclosed male Harlequin.


  • [C&P4] 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 Chng C K, Loke P F, Sunny Chir and Horace Tan

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