22 February 2014

Life History of the Common Five Ring

Life History of Common Five Ring (Ypthima baldus newboldi)


Butterfly Biodata:
Genus: Ypthima Hübner, 1818
Species: baldus Fabricius, 1775
Subspecies: newboldi Distant, 1882
Wingspan of Adult Butterfly: 30-40mm
Caterpillar Local Host Plant: Axonopus compressus (Poaceae, common names: Wide-leaved Carpet Grass, Cow Grass).



The upperside view of a female Common Five Ring.

The upperside view of a male Common Five Ring.

Physical Description of Adult Butterfly:
On the upperside, the wings are dull brown with the female being paler in the ground colour in the distal halves of both wings. Both sexes have a large yellow-ringed ocellus in space 2 of the forewing, and two smaller and adjoined yellow-ringed ocelli in spaces 2 and 3 of the hindwing (with another ocellus in space 5 in some specimens). 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. Some specimens might bear another small ocellus in space 4. The pair of ocelli in spaces 2 and 3 are large and adjoined, and the one in space 1b consists of two conjoined spots. The pair of ocelli in spaces 5 and 6 are typically adjoined, with the one in space 6 larger than the one in space 5.



Field Observations of Butterfly Behaviour:
The Common Five Ring is moderately common in Singapore,and are more commonly observed in the Southern Ridges. 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, only one grass species has been recorded as the larval host for the Common 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:Axonopus compressus.

A mating pair of the Common 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 0.85mm in height, 0.8mm in diameter) and pale translucent with a light bluish tinge. The surface is tessellated with moderately large polygonal faces.

A mother Common Five Ring laying an egg on another plant in the vicinity of its host plant.

Two views of an egg of the Common Five Ring.

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

The egg takes about 4.5-5 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 small protuberances.

Two views of a newly hatched caterpillar, length: 2.mm

As a result of its leaf diet, the 1st instar caterpillar soon takes on a strong greenish undertone. The first instar lasts about 3.5-4 days with the body length increases to about 4-4.5mm.

Two views of a 1st instar caterpillar, length: 2.5mm.

Two views of a late 1st instar caterpillar, dormant prior to its moult, length: 4.5mm.

In the 2nd instar, the cephalic "horns" are smaller, pointed and less distinct whilst the two anal processes become proportionately longer and pointed. The head is now pale translucent yellow to 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 3 days with the body length reaches about 6-6.5mm.

Two views of a 2nd instar caterpillar, early in this stage, 4.8mm.

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

Two views of a late 2nd instar caterpillar, dormant prior to its moult, length: 6.3mm.

The 3rd instar caterpillar mostly resembles its former self in the 2nd instar. The alignment of the numerous, small, whitish/yellowish tubercles in rows gives the caterpillar a banded appearance. This stage takes 3.5-4 days to complete with body length reaching about 9-9.5mm.

Two views of a newly moulted 3nd instar caterpillar.

Two views of a 3nd instar caterpillar, length: 9mm.

Two views of a late 3nd instar caterpillar, dormant prior to its moult, length: 9.5mm.

The 4th instar caterpillar bears a close resemblance to the 3rd instar caterpillar with no obvious change of any features or markings. The 4th instar lasts about 4.5-5 days with body length reaching 15mm.

Two views of a newly moulted 4th instar caterpillar, length: 9.3mm.

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

Two views of a late 4th instar caterpillar, dormant prior to its moult, length: 15mm.

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

The 5th instar caterpillar could appear in two colour forms: green form and brown form. It has a strongly banded appearance with a number of narrow bands, colours alternating between pale and darker green or pale brown and darker brown, running lengthwise. The dorsal band and spiracular bands are typically darker than the rest. 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 green-form specimens could develop pinky patches. In a period of 5-6 days, the body grows to a maximum length of about 24-26mm.

Two views of a newly moulted 5th instar caterpillar, length: 14.5mm.

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

Two views of a 5th instar caterpillar, green form, length: 26mm.

Two views of a 5th instar caterpillar, late in this stage, intermediate 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.

A prep-pupa of Common Five Ring. Left: early stage; Right: late stage.

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: 10.5-11mm.

A Common Five Ring caterpillar moults to its pupal stage.

Three views of a pupa of Common Five Ring.

After 7.5-8 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 Common Five Ring.

A Common Five Ring butterfly emerges from its pupal case.

A newly eclosed Common Five Ring.

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 Bobby Mun, Anthony Wong and Horace Tan

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