08 February 2014

Life History of the Malayan Five Ring

Life History of Malayan Five Ring (Ypthima horsfieldi humei )

Butterfly Biodata:
Genus: Ypthima Hübner, 1818
Species: horsfieldi Moore, 1884
Subspecies: humei Elwes & Edwards, 1893
Wingspan of Adult Butterfly: 30-40mm
Caterpillar Local Host Plant: Axonopus compressus (Poaceae, common names: Wide-leaved Carpet Grass, Cow Grass), Ottochloa nodosa (Poaceae), Kyllinga nemoralis (Cyperaceae, common name: White Kyllinga).

Physical Description of Adult Butterfly:
On the upperside, the wings are dull brown in the female and greyish brown in the male. Both sexes have a large yellow-ringed ocellus in space 2 of the forewing, and two smaller yellow-ringed ocelli in spaces 2 and 3 of the hindwing. The male has a broad strip of greyish black brand in the forewing. On the underside, both wings are pale greyish to bluff brown against a whitish background, and are traversed by numerous fine dark brown striae. The forewing has a large, bi-pupilled, yellow-ringed subapical ocellus. The hindwing has five yellow-ringed ocelli in spaces 1b, 2, 3, 5 and 6. The pair of ocelli in spaces 2 and 3 are well separated, and the one in space 1b consists of two conjoined spots.

Upperside view of a female Malayan Five Ring.

Upperside view of a male Malayan Five Ring.

Field Observations of Butterfly Behaviour:
The Malayan Five Ring is common in the nature reserves and surrounding vegetated areas. Adults are typically sighted flying low among vegetation in and around grassy patches. As with other Satyrinae members, the adults fly in an erratic and jerky manner. The adults visits flowers for nectar and sun-bathe with fully opened wings in sunny conditions.

Early Stages:
Thus far, three common grass species have been recorded as larval hosts for the Malayan Five Ring. The caterpillars feed on leaves of the host plant, and have been observed to forcefully ejecting their frass pellets, a larval habit rarely seen outside the skipper/flat families. They tend to rest lengthwise on the underside of a leaf during pauses between feeds.

Host plant #1: Axonopus compressus.

Local host plant #2: Ottochloa nodosa.

Host plant #3: Kyllinga nemoralis.

A mating pair of Malayan Five Ring.

The eggs are laid singly on the underside of a grass blade of the host plant or on other small plants or objects in the vicinity of the host plants. Each egg is nearly globular (about 0.9mm in height, 0.8-0.85mm in diameter) and pale translucent with a light bluish tinge. It appears to be smooth to the naked eyes, but faintly sculptured with a very fine polygonal grid when viewed with a macro lens.

A mother Malayan Five Ring laying an egg on a dry plant part among leaf litter.

Two views of an egg of the Malayan Five Ring.

Two views of a mature egg with the head faintly visible through the egg shell.

The egg takes about 4.5 days to mature. The young caterpillar nibbles away a portion of the egg shell to exit and then proceeds to devour the rest of the egg shell. It has a whitish, cylindrical body with small pink patches occurring dorsally and laterally. The initial body length is about 2mm. The body is covered with dorso-lateral and lateral rows of long setae. At the posterior end, there is a short pair of backward-pointing processes. Its pale brownish head features a few setae, a pair of short and rounded "horns" and a few lateral protuberances.

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

As a result of its leaf diet, the 1st instar caterpillar soon takes on a strong greenish undertone. The first instar lasts about 4 days with the body length increases to about 4-4.5mm.

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

Two views of a 1st instar caterpillar, length: 4mm.

Two views of a late 1st instar caterpillar, dormant prior to its moult, length: 4.3mm.

In the 2nd instar, the cephalic "horns" are less distinct and the two anal processes proportionately longer and pointed. The head is now pale translucent green and featuring a number of small, whitish tubercles. The body color is pale yellowish green and adorned with rows of numerous, whitish, minute tubercles, each with a single seta emanating from it. The 2nd instar lasts about 4-4.5 days with the body length reaches about 6.5mm.

Two views of a 2nd instar caterpillar, early in this stage, 4.3mm.

Two views of a 2nd instar caterpillar, length: 6mm.

Two views of a late 2nd instar caterpillar, dormant prior to its moult, length: 6.5mm.

The 3rd instar caterpillar mostly resembles its former self in the 2nd instar. This stage takes 4.5-5 days to complete with body length reaching about 10mm.

Two views of a newly moulted 3nd instar caterpillar.

Two views of a 3nd instar caterpillar, length: 9.5mm.

Two views of a late 3nd instar caterpillar, dormant prior to its moult, length: 9mm.

Again, there is no obvious change in the appearance of the caterpillar from the 3rd to the 4th instar. This penultimate instar lasts about 6-7 days with body length reaching 15-16mm.

Two views of a newly moulted 4th instar caterpillar, length: 8.5mm.

Two views of a 4th instar caterpillar, length: 13mm.

Two views of a late 4th instar caterpillar, dormant prior to its moult, length: 14.5mm.

Malayan Five Ring caterpillars in the act of catapulting frass pellets.

The next moult brings the caterpillar to its 5th and final instar. Now the caterpillar has a strongly banded appearance with a number of narrow whitish bands running lengthwise. There is a distinct whitish sub-spiracular band and the spiracles are black. Pairs of small black patches appear on the dorsum of several mid-body segments. The head capsule has additional small brown to black patches occurring on the front and laterally. As growth progresses, some specimens change from a greenish appearance (green form) to a pinky brown appearance (brown form). In a period of 8-9 days, the body grows to a maximum length of about 32-35mm.

Two views of a newly moulted 5th instar caterpillar, length: 13.5mm.

Two views of a 5th instar caterpillar, green form, length: 17mm.

Two views of a 5th instar caterpillar, brown form, length: 22.5mm.

Two views of a 5th instar caterpillar, green form, length: 24mm.

Toward the end of the 5th instar, the body gradually shrinks in length. Finally the caterpillar finds a spot on the underside of a leaf blade or a stem to spin a silk pad. It then secures itself there via its anal end, and assumes its upside-down pre-pupatory pose.

Two prep-pupae of Malayan Five Ring. Left: green form; Right: brown form.

After one day as a pre-pupa, pupation takes place. The slender pupa has a beige brown ground colour with numerous small brown/black patches. There are two low transverse dorsal ridge on abdominal segments 3 and 4, and a longitudinal dorsal ridge on the thorax. Length of pupae: 11.5-12mm.

A Malayan Five Ring caterpillar moults to its pupal stage.

Three views of a pupa of Malayan Five Ring.

After 7 days of development, the pupa becomes darkened in color, and the ringed-spot on the forewings can now be seen through the pupal skin in the wing pads. The next day the eclosion event takes place with the adult butterfly emerges to start the next phase of its life cycle.

Three views of a mature pupa of Malayan Five Ring.

A Malayan Five Ring butterfly emerges from its pupal case.

A newly eclosed Malayan Five Ring.

  • [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 Benedict Tay, Jayne Kok, Simon Sng, Federick Ho, Khew SK and Horace Tan

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