Life History of the Large Snow Flat (Tagiades gana gana)
Butterfly Biodata:
Genus: Tagiades Hübner, 1819
Species: gana Moore, 1866
Sub-species: gana Moore, 1866
Wingspan of Adult Butterfly: 38-45mm
Caterpillar Local Host Plants: Dioscorea pyrifolia (Dioscoreaceae), Dioscorea orbiculata var. tenuifolia (Dioscoreaceae) and other Dioscorea spp.
Physical Description of Adult Butterfly:
Field Observations of Butterfly Behaviour:
This species is common in Singapore and can be found in the forested areas in the Central Catchment and Bukit Timah nature reserves, and several other sites across the island. The adults are rapid flyers and are more active in the cooler hours of the day. As is the case for the other Tagiades species, the adults have the habit of perching on the underside of a leaf between flights, and with wings opened flat. The adults are often seen visiting flowers for nectar.
Early Stages:
Several Dioscorea spp. have been found to be the local host plants for the Large Snow Flat. Only two of them have been formally identified. The caterpillars of the Large Snow Flat feed on leaves of the host plant. When not feeding, the caterpillars seek safety and concealment in a leaf shelter formed by cutting and folding a leaf fragment along the edge of the leaf.
Local host plant #1: Dioscorea pyrifolia.
Local host plant #2: Dioscorea orbiculata var. tenuifolia.
Leaf shelter of a 2nd instar caterpillar of the Large Snow Flat.
A mating pair of the Large Snow Flat.
The eggs of the Large Snow Flat are laid singly on the underside of a leaf of the host plant. The pale yellowish is hemispherical with surface marked with longitudinal ridges running from the pole to the rim of the base. The egg is well concealed in a mass of fine whitish to pale yellowish setae deposited by the mother butterfly. Each egg has a diameter of about 0.9mm.
Two views of an egg of the Large Snow Flat.
Left: a maturing egg; Right : a mature egg with the polar portion of the egg shell already nibbled away.
The egg takes about 5 days to hatch. The young caterpillar emerges by eating away the polar portion of the egg shell. The rest of the egg shell is not eaten by the newly hatched which is about 3mm in length. The dull orange body is reddish laterally and feature a few moderately long setae at its anal end. The head capsule is black in color, and there is a black collar mark on the dorsum of the prothorax.
Two views of a 1st instar caterpillar, early in this stage, length: 3mm.
The newly hatched makes its way to the leaf edge to construct its very first leaf shelter. It ventures out of the shelter from time to time to feed on the leaf lamina in the vicinity. As the caterpillar grows, the body assumes a green undertone. After reaching about 5mm in about 3 days, the caterpillar moults to the 2nd instar.
Two views of a 1st instar caterpillar, length: 4.5mm.
Two views of a late 1st instar caterpillar, dormant prior to its moult.
The body of the 2nd instar caterpillar is initially dull orange but becoming more yellowish as it grows in this instar. The lateral reddish coloration also dissipates in the same time frame. There are numerous, obscure and whitish specks carpeting the body surface. The black colar mark on the prothorax is still present but has become obscure. The dark reddish brown head is broadened sideways to two rounded tips at the upper end. This instar lasts about 4 days with the body length reaching about 8mm.
Two views of a 2nd instar caterpillar, early in this stage, length: 4.2mm.
Two views of a 2nd instar caterpillar, length: 5.8mm.
A late 2nd instar caterpillar, dormant prior to its moult, length: 8mm.
The 3rd instar caterpillar closely resembles the 2nd instar caterpillar. The head capsule is still dark reddish brown but broader sideways and with the two raised points more pronounced, resulting in a heart-shaped outline. The whitish/yellowish specks on the body are now more prominent. This instar takes about 5 days to complete with body length reaching about 12mm.
Two views of a 3rd instar caterpillar, early in this stage, length: 7.5mm.
Two views of a 3rd instar caterpillar, length: 12mm.
Two views of a late 3rd instar caterpillar, dormant prior to its moult.
The 4th instar caterpillar is little changed from the 3rd instar. The yellowish green body is covered with numerous, yellowish specks, and there is hardly any hint of a dark collar mark on the prothorax. This instar lasts about 6 days with body length reaching about 21-22mm.
Two views of a 4th instar caterpillar, early in this stage, length: 12.5mm.
Two views of a 4th instar caterpillar, late in this stage, length: 22mm.
Two views of a late 4th instar caterpillar, dormant prior to its moult.
The 5th instar caterpillar has similar body markings as in the 4th instar. The yellow coloration of the body ground colour and that of the numerous specks is more mellow than in the earlier instar. This final instar lasts for about 8-9 days, and the body length reaches up to 33-40mm.
Two views of a 5th instar caterpillar, early in this stage, length: 22mm.
Two views of a 5th instar caterpillar, length:30mm.
Two views of a 5th instar caterpillar, late in this stage, length:28mm.
Top: A pre-pupa of the Large Snow Flat secured with silk girdle in its shelter. Bottom: The fresh pupa, note the change to cremastral attachment at the posterior end.
Two views of a pupa of the Large Snow Flat.
Left: Frontal view of the anterior of a pupa of the Large Snow Flat. Right: Close-up view of the cremastral attachment.
Two views of a mature pupa of the Large Snow Flat .
A newly eclosed adult of the Large Snow Flat .
References:
Genus: Tagiades Hübner, 1819
Species: gana Moore, 1866
Sub-species: gana Moore, 1866
Wingspan of Adult Butterfly: 38-45mm
Caterpillar Local Host Plants: Dioscorea pyrifolia (Dioscoreaceae), Dioscorea orbiculata var. tenuifolia (Dioscoreaceae) and other Dioscorea spp.
Physical Description of Adult Butterfly:
Above, the wings are brown with obscure post-discal and discal spots in darker brown. On the forewing, there are three white hyaline sub-apical spots in spaces 6,7,8. On the hindwing, the tornal area is whitened and there are black marginal spots at the end of veins 2, 3 and 4, and in some specimens, another spot at the end of vein 1b. Below, the wings are similarly marked as per above but with the whitened area on the hindwing extended to the basal area and almost to the costal margin.
Field Observations of Butterfly Behaviour:
This species is common in Singapore and can be found in the forested areas in the Central Catchment and Bukit Timah nature reserves, and several other sites across the island. The adults are rapid flyers and are more active in the cooler hours of the day. As is the case for the other Tagiades species, the adults have the habit of perching on the underside of a leaf between flights, and with wings opened flat. The adults are often seen visiting flowers for nectar.
Early Stages:
Several Dioscorea spp. have been found to be the local host plants for the Large Snow Flat. Only two of them have been formally identified. The caterpillars of the Large Snow Flat feed on leaves of the host plant. When not feeding, the caterpillars seek safety and concealment in a leaf shelter formed by cutting and folding a leaf fragment along the edge of the leaf.
The eggs of the Large Snow Flat are laid singly on the underside of a leaf of the host plant. The pale yellowish is hemispherical with surface marked with longitudinal ridges running from the pole to the rim of the base. The egg is well concealed in a mass of fine whitish to pale yellowish setae deposited by the mother butterfly. Each egg has a diameter of about 0.9mm.
The egg takes about 5 days to hatch. The young caterpillar emerges by eating away the polar portion of the egg shell. The rest of the egg shell is not eaten by the newly hatched which is about 3mm in length. The dull orange body is reddish laterally and feature a few moderately long setae at its anal end. The head capsule is black in color, and there is a black collar mark on the dorsum of the prothorax.
The newly hatched makes its way to the leaf edge to construct its very first leaf shelter. It ventures out of the shelter from time to time to feed on the leaf lamina in the vicinity. As the caterpillar grows, the body assumes a green undertone. After reaching about 5mm in about 3 days, the caterpillar moults to the 2nd instar.
The body of the 2nd instar caterpillar is initially dull orange but becoming more yellowish as it grows in this instar. The lateral reddish coloration also dissipates in the same time frame. There are numerous, obscure and whitish specks carpeting the body surface. The black colar mark on the prothorax is still present but has become obscure. The dark reddish brown head is broadened sideways to two rounded tips at the upper end. This instar lasts about 4 days with the body length reaching about 8mm.
The 3rd instar caterpillar closely resembles the 2nd instar caterpillar. The head capsule is still dark reddish brown but broader sideways and with the two raised points more pronounced, resulting in a heart-shaped outline. The whitish/yellowish specks on the body are now more prominent. This instar takes about 5 days to complete with body length reaching about 12mm.
The 4th instar caterpillar is little changed from the 3rd instar. The yellowish green body is covered with numerous, yellowish specks, and there is hardly any hint of a dark collar mark on the prothorax. This instar lasts about 6 days with body length reaching about 21-22mm.
The 5th instar caterpillar has similar body markings as in the 4th instar. The yellow coloration of the body ground colour and that of the numerous specks is more mellow than in the earlier instar. This final instar lasts for about 8-9 days, and the body length reaches up to 33-40mm.
On the last day of 5th instar, the body decolorises to an iridescent shade of pink. The caterpillar ceases feeding and remains in its leaf shelter. In it, the pre-pupatory larva prepares for the pupal phase with a series of silk construction work with the main pieces being a silk girdle across the dorsum of its early abdominal segments, and a short and thickened transverse silk band on the substrate at its posterior end. Pupation takes place about 1 day later.
The girdled pupa is secured with its cremaster attached to the short transverse band on the substrate. It has a short thorax, a rather long abdomen, a pointed rostrum and two small ear-like appendages at the leading edge of the mesothorax. The body is pale beige brown dotted with numerous brown to reddish brown spots. Unlike other Tagiades spp., the pupa doe snot have white triangular patches on the sides of its body. Length of pupae: 24-25mm.
After about 8 days of development, the pupal turns dark as the development within the pupal case comes to an end. The following day, the adult butterfly emerges from the pupal case.
References:
- [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, 2nd Edition, 2012.
- A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2010.
