Senin, 02 April 2012

the Common Jay (Graphium doson evemonides)

Butterfly Biodata:
Genus: Graphium Scopoli, 1777
Species: doson
C & R Felder, 1864
Subspecies: evemonides
Honrath, 1884
Wingspan of Adult Butterfly: 50-65mm
Local Caterpillar Host Plants:
Desmos chinensis (Annonaceae, common name: Dwarf Ylang Ylang), Michelia alba (Magnoliaceae, common name: White Champaca), Polyathia longifolia var. pendula (Annonaceae, common name: False Ashoka Tree).

A Common Jay found on damp ground.

A Common Jay perching on a leaf.

Physical Description of Adult Butterfly:
As with most Graphium species, the wings are produced at the forewing apex and hindwing tornus, and the inner margin of the hindwing bends inwards. Above, the wings are black with a broad bluish-green macular band running from the sub-apical area of the forewing to the basal area of the hindwing. There is also a series of bluish-green streaks in the cell of the forewing. A series of bluish-green submarginal spots is present in both fore- and hindwings. Underneath, the same spotting pattern can be found against a dark brown base, with the spots larger and more silvery green. Additional red and black spots are featured on the hindwing. There is a dark red-centred costal bar sited right in the silvery middle cross band of the hindwing. In Singapore, the presence of this costal bar is the main distinguishing feature between Common Jay and the more commonly found Blue Jay.

A puddling Common Jay.

A Common Jay perching on a leaf in a hill park.

Field Observations of Butterfly Behaviour: Although the Common Jay is common in neighbouring Malaysia, it has only been recently discovered in Singapore on the offshore island of Pulau Ubin in 2005. It is not listed in the original butterfly checklist for Singapore, and is believed to have migrated from nearby Johor in Malaysia and established its presence in P. Ubin where one of its host plants is available in relative abundance. There has only been one isolated sighting of an individual in mainland Singapore in late 2006. The swift-flying adults haven been sighted visiting flowers, and making ovipositing visits to the host plants. The males of this species can be found puddling along damp foot paths.

A Common Jay perching on a grass blade in an open field.

A male Common Jay.

Early Stages:
With its wide distribution and common occurrence in the region outside Singapore, early stages of the Common Jay have been documented earlier, and its many host plants already identified by researchers and enthusiasts working in these areas. In Singapore, the early stages of the Common Jay feed on young leaves of several plants in the Annonaceae and Magnoliaceae families. One host, Desmos chinensis, grows in relative abundance in P. Ubin and seems to be the host of choice for the Common Jay in that habitat. Eggs and early stages of the Common Jay are typically found on young leaves of this host at low heights.

Local host plant #1, Desmos chinensis (Dwarf Ylang Ylang).

Local host plant #2 : Polyathia longifolia var. pendula (False Ashoka Tree).

A mother Common Jay laying an egg on a young leaf of Desmos chinensis in Pulau Ubin.

The eggs of the Common Jay are laid on young leaves of the host plant on either the upper- or undersides. The spherical egg is initially creamy white with a diameter of about 1.0-1.1mm. As it matures, it gradually turns yellow.

Two views of an egg of the Common Jay.

Two views of a mature egg of the Common Jay. Note the outline of the head capsule and the mandibles which are now visible through the egg shell.

Three views of a newly hatched Common Jay nibbling away at the egg shell. Note the darkening of body color from 1st to 2nd pic.

The egg takes 3-4 days to hatch, and the newly hatched has a body length of about 2.2mm. The entire egg shell is consumed by the newly hatched as its first meal. The body is initially pale yellowish but turning dark brown gradually and this happens even as the egg shell is being consumed. The last abdominal segment is white in color in contrast. A pair of brown lateral spines can be found on each of the three thoracic segments, and another white pair at the anal segment. The body also features rows of short dorsal-lateral tubercles with long setae. The head capsule is yellowish brown.

Two views of a newly hatched Common Jay caterpillar.

Two views of a 1st instar caterpillar, , length: 3.5mm

Between feeds, the Common Jay caterpillar of all instars rests on the upper leaf surface, usually alongside the midrib. After about 3-3.5 days of feeding, the 1st instar caterpillar grows to a length of about 5.5-6mm. The moult to the 2nd instar takes place after a period of inactivity.

A first instar caterpillar found resting on the upperside midrib of a young leaf of Desmos chinensis in the field.

In the 2nd instar, the thoracic segments are much enlarged from the 2nd to 3rd segment. The thoracic and anal pairs of spines are rather drastically reduced in size in proportion to the body. Between them, the prothoracic pair is longer compared to the other two. The head capsule is still yellowish brown but has an increase in orange tone. The body remains dark brown throughout this instar and t
he sub-spiracular area of the abdominal segments are whitish. This instar lasts for 1.5-2 days, and has the body length increased up to about 8mm.

Two views of a 2nd instar caterpillar, late in this stage, length: 7.2mm

Field shots of a 2nd instar Common Jay caterpillar on the same leaf over the course of 2 hours.
Left: resting on the midrib near its 1st feeding site; Right: feeding at a 2nd site.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely. The head capsule is orangy brown at this stage. In about 3 days, the caterpillar grows to about 15mm in length before the moult to the 4th instar takes place.

Two views of a 3rd instar caterpillar, length: 12mm.

The body of the 4th instar caterpillar is initially dark brown soon after moulting but turning much paler yellowish brown for most part of this instar. The caterpillar has a pale orangy brown head capsule, and the base of the metathoracic pair of splines is vaguely encircled in ring of yellow or pale brown. The dark thoracic pairs of spines also take on a bluish sheen when viewed at certain perspectives. Now the sub-spiracular area of all body segments are whitish to varying extent. This instar lasts about 3-4 days with the body length reaching about 24mm.

Two views of a newly moulted 4th instar caterpillar, eating its exuvia, length: 15mm.

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

A Common Jay caterpillar moulting to its final (5th) instar.

The 5th instar caterpillar resembles the late 4th instar caterpillar, but with the metathoracic pair of splines larger and more prominently marked with a black-outlined yellow to yellowish brown ring at the base, and the mesothoracic pair minuscule or even absent. The last abdominal segment is no longer white but follows the same coloration as the other segments. Each of the two anal splines is still whitish but takes on a black stripe on its outer edge. Soon after moulting, the body color is yellowish brown. In some individuals, the body soon changes to a green to dull green coloration, whilst others remain yellowish brown until in the last day of this instar before the color change takes place. The 5th instar lasts for 4-5 days, and the body length reaches 39-44mm.

Two views of a 5th instar caterpillar, early in this stage, length: 24mm.

Two views of a 5th instar caterpillar, yellowish brown form, length: 28mm.

Two views of a 5th instar caterpillar, green form, length: 35mm.

Toward the end of the 5th instar, the body gradually shortens in length and turns completely pale greenish. The caterpillar wanders around for a pupation site and eventually comes to rest on one spot of a leaf in an upright position. Here the caterpillar prepares and secures itself with a a silk pad and a silk girdle.

A 5th instar Common Jay caterpillar found in the field.

Two views of a pre-pupatory larva of the Common Jay.
Pupation takes place a day later. The pupa is pale yellowish green, about 27-30mm in length and has a slender and obtusely pointed mesothoracic horn. There are two short and blant cephalic horns. The abdomen has two dorsal carinae which are whitish to pale yellowish and run laterally and continuously to the tip of the mesothoracic horn.

The pupation event of a Common Jay caterpillar.

Two views of a pupa of the Common Jay.

The pupal period lasts for 9 days, and the pupa turns black in the wing pads the night before eclosion. The bluish-green spots on the forewings are visible through the pupal skin at this stage. The adult butterfly emerges the next morning to commence the adult phase of its life cycle.

Two views of a mature Common Jay pupa.

The eclosion event of a Common Jay butterfly.

A newly eclosed Common Jay clinging on to its pupal case.

  • [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, 1st Edition, 2006
Text by Horace Tan, Photos by Sunny Chir, Khew SK and Horace Tan
Special thanks to Prof Hugh Tan, Department of Biological Sciences, NUS, and a NParks staff at Ubin for their kind assistance in providing ID for the host plant, Desmos chinensis.