Life History of the Common Rose

Life History of the Common Rose (Pachliopta aristolochiae asteris)

Butterfly Biodata:
Genus: Pachliopta Reakirt, 1865
Species: aristolochiae Fabricius, 1793
Subspecies: asteris Rothschild, 1908
Wingspan of Adult Butterfly: 65-85mm
Caterpillar Local Host Plants:  Aristolochia acuminata (Aristolochiaceae, common names: Indian Birthwort, Dutchman's Pipe), Aristolochia elegans (Aristolochiaceae, common names: Calico flower, Pipe Vine).

Physical Description of Adult Butterfly:

Above, both sexes are black with the distal part of the forewing grey-shaded between the veins.The hindwing has a large white post-discal patch and a number of greyish-red submarginal crescent-shaped spots. Underneath, both sexes bear similar markings as per the upperside, but with the submarginal spots on the hindwing rounded and in striking red. The hindwing has a moderately long tail at vein 4. The body is bright red. The female has rounder wing contours than the male.

Field Observations of Butterfly Behaviour:

Common Rose is moderately common in Singapore and are often observed at the Singapore Botanic Gardens, Singapore Zoo, Hort Park and other locations where its host plants, Aristolochia spp., are cultivated. The adults are strong flyers and have been observed to visit flowers and puddle on wet ground.

Early Stages:

The recorded local host plants, Aristolochia acuminata and Aristolochia elegans, are perennial vines and can be found cultivated in various locations locally. In the wild, A. acuminata can also be found in forests and open lowland thickets. The caterpillars of the Common Rose feed on the leaves and the young shoots of both plants.

Host plant #1: Aristolochia elegans.

Host plant #2: Aristolochia acuminata.

The eggs of the Common Rose are laid singly on the surface of a leaf of the host plant. The orange-colored egg is coated unevenly with a yellowish material. It is nearly spherical with a diameter of about 1.3-1.4mm.

A mother Common Rose probing a leaf of Aristolochia acuminata for oviposition.

Two views of an egg of Common Rose.

Two views of a mature egg of the Common Rose.

The egg takes about 3 days to hatch. The young caterpillar eats its way out of the mature egg, and then proceeds to finish up the rest of the egg shell. It has an inital body length of about 2.5mm. There are short dorsal-lateral and lateral processes (one pair to each body segment)with tuffs of dark setae emanating from them. The body is reddish brown and the head is dark brown to black.

A new hatched caterpillar nibbling at the egg shell.

Two views of a newly hatched caterpillar, length: 2.5mm..

As the 1st instar caterpillar grows up to a length of about 5mm, the dorso-lateral pair of processes on the 3rd abdominal segment turn whitish. The lst instar lasts for 2.5-3 days.

Two views of a 1st instar caterpillar, length: 3.3mm.

Two views of a 1st instar caterpillar, late in this stage, dormant prior to its moult, length: 5mm

In the 2nd instar, the dorso-lateral and lateral pairs of processes are fleshy and proportionately longer than those present in the 1st instar. Initially, these processes, except for the whitish ones on the 3rd abdominal segment, are initially dull orange and the body dark purplish brown. As growth progresses, these processes and the body turn to a uniform shade of wine-red. In the meantime, the 3rd abdominal segment turns mostly whitish, forming the so-called white saddle mark. Towards the end of this instar, the body colour turns dark for the most part as the caterpillar lays dormant prior to its moult. This instar lasts about 2 days with the body length reaching up to 9mm.

Two views of a 2nd instar caterpillar, newly moulted, length: 5mm.

Two views of a 2nd instar caterpillar, length: 8.8mm

Two views of a late 2nd instar caterpillar, dormant prior to its moult, length: 8mm.

In the 3rd instar, the fleshy processes are proportionately longer and more pointed, the body is in a dark shade of reddish brown while the distal end of body processes are in a contrasting wine red. The white saddle mark on the 3rd abdominal segment is now rather prominent. This instar takes about 2 days to complete with the body length reaching up to 14mm.

Two views of a newly moulted 3rd instar caterpillar, with exuvia nearby.

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

The 4th instar caterpillar resembles the 3rd instar caterpillar closely. This penultimate instar lasts about 2-2.5 days with body length reaching about 24mm.

Two views of a newly moulted 4th instar caterpillar, length: 14mm.

Two views of a 4th instar caterpillar, length: 23mm.

The next moult brings the caterpillar to its 5th and final instar with no obvious change in markings or coloration. The body processes are not as proportionately long nor fleshy than those present in the earlier instars.

Two views of a 5th instar caterpillar, freshly moulted, length: 22mm.

Two views of a 5th instar caterpillar, late in this stage, length: 36mm.

A Common Rose caterpillar observed on A. elegans in a urban park.

Another Common Rose caterpillar observed on A. acuminata in another urban park.

As in the case of all Swallowtail butterflies, the Common Rose caterpillars in all instars possess a fleshy organ called osmeterium in the prothoracic segment. Usually hidden, the osmeterium can be everted to emit a foul-smelling secretion when the caterpillar is threatened.

A 4th instar Common Rose caterpillar displaying its orange-colored osmeterium.

The 5th instar lasts for about 4-4.5 days, and the body length reaches up to 38mm. Toward the end of this instar, the body gradually shortens in length. Eventually the caterpillar comes to rest on the under surface of a stem or a leaf. Here it stays dormant for a while before performing a purge of loose and wet frass pellets. It then spins a silk pad and a silk girdle to become an immobile pre-pupatory larva.

A pre-pupatory larva of the Common Rose.

Pupation takes place a day later. The orange/reddish-brown pupa suspends itself with a silk girdle from the stem and with its cremaster attached to the silk pad at the lower end. The pupa has an arched profile, bending at the start and middle of the abdomen. There are a few pairs of fin-like dorso-lateral and a pair of cephalic horns. Length of pupa: 28-30mm.

Two views of a pupa of the Common Rose.

After 11-11.5 days, the pupa turns black as the development within the pupal case draws to a close. The next morning the adult butterfly emerges from the pupal case.

Two views of a mature pupa of the Common Rose.

A newly eclosed Common Rose clinging onto its pupal case.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society, 1992.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012.
• A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2010.

Text by Horace Tan, Photos by Goh Lai Chong, James Chia, Nelson Ong, Sunny Chir and Horace Tan