Butterfly Biodata:
Genus: Danaus Kluk, 1802
Species: chrysippus Linnaeus, 1758
Subspecies: chrysippus Linnaeus, 1758
Wingspan of Adult Butterfly: 65mm
Caterpillar Local Host Plant: Calotropis gigantea (Asclepiadaceae, common name: Giant Milkweed), Asclepias curassavica (Asclepiadaceae, common name: Blood Flower).
A Plain Tiger found visiting a flower.
Physical Description of Adult Butterfly:
Above, the forewings are orangey brown with a series of white spots in a broad black apical border. The hindwings have a narrow dark border and a few black spots featured at both the cell edge and end-cell. In form chrysippus, the hindwings are orangy brown, but in form alcippoides, the hindwings are almost white throughout. The male has a subtornal brand on the hindwing just below vein 3. Underneath, the wings are similarly marked as per the upperside but with apical border orangy brown on the forewing, and wing margins marked with a series of prominent and white marginal spots.
A Plain Tiger form chrysippus sunbathing on a fern frond.
Plain Tiger adults imbibing fluid/sap from parts of two different plants.
Field Observations of Butterfly Behaviour: Both forms of the Plain Tiger can be found in Singapore with form alcippoides being the more common of the two. This species is typically found where its host plants are cultivated. Such locations include HortPark, butterfly trails, butterfly gardens in schools and housing estates and even certain park connectors. The adults typically visits flowers in the vicinity of its host plant and has a fondness for sap exuded by Crotalaria spp.
A Plain Tiger perching on a fern frond in a closed-wing pose.
A newly eclosed Plain Tiger
Early Stages:
Caterpillars of Plain Tiger feed on leaves of its host plants, Giant Milkweed and Blood Flower, both of the Asclepiadaceae family (the Milkweed family).
Local host plants for the Plain Tiger: Giant Milkweed (left) and Blood Flower (right).
The eggs of the Plain Tiger are laid singly on the leaf of the host plant, typically on the underside. The milky white egg is shaped somewhat like a bullet-head (diameter: 0.95mm, height: 1.3mm). The egg surface is ribbed with ridges running longitudinally. The micropyle sits atop.
The egg takes about 2.5-3 days to hatch. The young caterpillar emerges by eating away part of the egg shell. The rest of the egg shell becomes the first meal for the newly hatched, which has a length of about 2.2mm. Its cylindrical body is mostly white with a yellowish undertone, and has a fair number of short fine setae. The large head capsule is black in color and there is a small black patch at the posterior end. A pair of short sub-dorsal protuberances can be found on each of the following four segments: 1st and 2nd thoracic segments, 2nd and 8th abdominal segments. Of these, the prothoracic pair is black in color and the remaining pairs in orangey brown. The thoracic legs and prolegs are all black in color.
Two views of a newly hatched caterpillar, length: 2.2mm.
Once the newly hatched moves on to feed on leaf lamina over the next few hours, its body starts to take on a green undertone. The growth is rather rapid with the body length doubling to about 4.5mm in 1.5 day, and after just 1.5 to 2 days from hatching, it moults to the 2nd instar. Towards the final hours of the 1st instar, the last three pairs of protuberances turn dark brown and pairs of oval-shaped yellow spots appear on the dorsum from the 2nd thoracic segment to the 8th abdominal segment.
Two views of a 1st instar caterpillar, length: 3.5mm.
Two views of a 1st instar caterpillar, late in this stage, length:4.3mm.
The body of the 2nd instar caterpillar is whitish in ground color. One obvious change is the lengthening of those black protuberances on the 2nd thoracic segment, 2nd and 8th abdominal segments The pair of protuberances on the 1st thoracic segment remains subdued in size. A diffused yellow band runs sub-spiracularly. The subdorsal paired yellow spots are embedded in dark patches which extend laterally to the subspiracular yellow band. Noteworthy is that there is only one (rather than two) elongated yellow dorsal spot on the 9th abdominal segment. The black head capsule now has a triangular white patch on the frons and a prominent white arch. This instar lasts only 1 to 1.5 days with the body length reaching 9mm before the moult to the 3rd instar.
Two views of a 2nd instar caterpillar, early in this stage, length: 5.7mm
Two views of a 2nd instar caterpillar, late in this stage, length: 8.5mm
The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar, One obvious change is in the three pairs of processes which are proportionately longer. The head capsule also has an outer white arch at the rear periphery. This instar takes about 1-1.5 days to complete with body length reaching about 12mm.
3rd instar caterpillar, newly moulted, length: 8.5mm
3rd instar caterpillar, late in this stage, length: 12mm.
Retaining very much the same body features from the previous instar, the 4th instar caterpillar distinguishes itself in having proportionately longer processes, with the mesothoracic pair the longest and having a strong tendency to flex forward. This instar lasts 2 days with the body length reaching about 21mm.
Two views of a 4th instar caterpillar, late in this stage, length: 12mm.
Two views of a 4th instar caterpillar, late in this stage, length: 16mm.
4th instar caterpillar, late in this stage, length: 21mm.
A group of Plain Tiger caterpillars defoliating a Blood Flower plant.
The 5th and final instar appears similar to the previous two instars but again with proportionately longer and filamentous processes, particularly so for the mesothoracic pair. All six processes now have a crimson coloration at the basal portion.
Two views of a 5th instar caterpillar, early in this stage, length: 26mm.
Two views of a 5th instar caterpillar, length: 34mm.
Two views of a 5th instar caterpillar, late in this stage, length: 39mm.
The 5th instar lasts for 2-3 days, and the body length reaches up to 42mm. On the last day, the caterpillar ceases feeding, and its body becomes shortened and decolorized, most notably in the yellow and crimson coloration. It wanders around in search of a pupation site. Typically it comes to a halt on a branch/stem or a leaf underside, where the caterpillar spins a silk pad from which it soon hangs vertically to take on the pre-pupatory pose.
A pre-pupatory larva of the Plain Tiger.
Pupation takes place about 0.75 days after the caterpillar assumes the hanging posture. The barrel-shaped pupa suspends itself from the silk pad with no supporting silk girdle. The pupa could be green, pink even white in coloration. It has a median transverse line marked with a series of black spots and an outer series of yellow spots. Length of pupae: 19-20mm.
Two views of a pupa of the Plain Tiger, green form.
Two views of a mature pupa of the Plain Tiger.
After about 5 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The prominent white spots on the forewing upperside also become discernible. The following day, the adult butterfly emerges from the pupal case.
A newly eclosed Plain Tiger drying its wings on its pupal case.
References:
- The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
- Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006
