28 February 2015

Life History of the Grand Imperial

Life History of the Grand Imperial (Neocheritra amrita amrita)

Butterfly Biodata:
Genus: Neocheritra Distant, 1885
Species: amrita
C & R Felder, 1860
Sub-species: amrita C & R Felder, 1860

Wingspan of Adult Butterfly: 36-40mm
Caterpillar Local Host Plant:
To be identified.

Physical Description of Adult Butterfly:
On the upperside, the male is dark brown with inner and basal halves of both wings in shining blue. The female is almost entirely brown. Both sexes have whitened tornal areas in the hindwing bearing large black quadrate marginal and submarginal spots. On the underside, both sexes are mainly yellowish orange but white in the lower half of the hindwing. Black post-discal striae are present in the tornal half of the hindwing. In the forewing, the basal part of vein 12 is not black (this is a key characteristic for distinguishing the Grand Imperial from the Great Imperial). In the hindwing, there are whitish tails at the end of veins 1b and 2 with the one at vein 1b much longer (about 2.5x as long as the one at vein 2) and fluffy in appearance.

A sunbathing female Grand Imperial displaying its upperside.

Field Observations of Butterfly Behaviour:
This species is rare in Singapore. The handful of sightings took place mainly in the catchment reserves, as well as the offshore island, Pulau Tekong. The adults have a graceful flight and typically perch with its wings closed upright between flights. In sunny weather, however, they have been observed to sun-bathe with wings fully open. They are sometimes sighted while hanging around a flowering plant for their nectar intake.

21 February 2015

Favourite Nectaring Plants #6

Butterflies' Favourite Nectaring Plants
The Javanese Ixora (Ixora javanica)

This 6th instalment of our Butterflies' Favourite Nectaring Plants series features a species of the family Rubiaceae, Ixora javanica. The genus Ixora comprises a number of species, which are generally bushy plants with bright red, pink, orange, yellow and white flowers. These plants are typically used as accent plants (particularly the red flowered cultivar) in landscapes in our parks and gardens.

The attractive bunches of red flowers make the Ixora a good choice for garden border hedges and as standalone feature bushes. In Singapore, the red and yellow varieties are more often cultivated in our urban streetscape and gardens. Other species like Ixora coccinea, Ixora siamensis (dwarf cultivar), Ixora chinensis and others are also cultivated, often together with Ixora javanica in our urban greenery, often making the identification of the various Ixora spp. rather confusing.

Plant Biodata :
Family : Rubiaceae
Genus : Ixora
Species : javanica
Synonyms : I. amara, I. amoena, I. cyathosperma
Country/Region of Origin : Tropical Southeast Asia
English Common Names : Javanese Ixora, Jungle Geranium, Jungle Flame
Other Local Names : Todong Periuk, Pechah Periuk, Bunga Siantan, Jejarum/Jarum-Jarum, 爪哇龍船花

The Javanese Ixora is a native plant in Southeast Asian countries like Indonesia, Malaysia, Singapore and Thailand. In Singapore, most of the Javanese Ixora bushes are cultivated and the plant appears in many parks and gardens as part of the horticultural palette of the garden designers. One species of the genus, Ixora congesta occurs naturally in the forests and is common on Pulau Ubin.

The short petiole (the stalk attaching the leaf blade to the stem) is a distinguishing feature

An evergreen shrub that grows up to 3 m tall, the Javanese Ixora features light green, elliptic-oblong leaves ranging from 10-25cm long. The leaves can sometimes be corrugated, but has a distinct short petiole, which is one of the diagnostic features to distinguish this Ixora from closely related ones. The leaves are paired and tend to droop downwards.

Inflorescence and flowers of the red and yellow cultivars of Ixora javanica

The inflorescence has quite a long peduncle, and the small tubular flowers have 4 obovate lobes arranged in a cross-like pattern, with the lobes bluntly pointed. Freshly opened flowers are red-orange, slowly turning red as they mature. Flowers are arranged in large, dense clusters that are about 7.6 cm wide.

Berry-like fruits of Ixora javanica

After pollination, the flowers die off, leaving the remaining stems on the clusters. Green, berry-like fruits appear, growing up to about 8-10mm in diameter and turning purple-black as they mature. The Ixora bushes also tend to get woody as the bushes grow older and may need to be pruned regularly to maintain its lush form and ability to flower regularly.

I recall that in my younger days, we pulled out the stamen from each flower, and usually attached to the ends of the stamens would be a drop of nectar which we savoured. The distinct sweetness of the flower's nectar is likely to be what attracts myriad insects to the flowers to feed.

Ixora javanica bushes at a Reservoir Park

In Singapore, many parks, gardens, park connectors, natureways and urban landscapes which have been cultivated to enhance our biodiversity features the Javanese Ixora. Favourite butterfly-photography (and birds too!) locations that feature this plant are Pulau Ubin's Butterfly Hill, Jurong Eco Gardens, Gardens By the Bay, Upper Seletar Reservoir Park and Upper Peirce Reservoir Park, to name a few.

Swallowtails galore!  Papilionidae species feeding on both the red and yellow flowers of Ixora javanica

Given the structure of the flower and the relative concentration of nectar, the flowers of the Javanese Ixora are attractive to both large and small butterflies. Amongst the larger Papilionidae that feed on the flowers are the Common Birdwing, Great Mormon, Common Mormon, Banded Swallowtail and Common Mime. As is typical with the Papilinidae, the butterflies are usually in flight, with their forewings flapping rapidly, whilst their hindwings are kept still and then probing their proboscis into the flower in search of nectar.

Pieridae species feeding on red and yellow flowers of Ixora javanica

Amongst the other families, we have come across Pieridae, various other subfamilies of the Nymphalidae, all medium or fairly large butterflies, feeding on the flowers of the Ixora javanica. The typical behaviour of these butterflies when feeding on Ixora is that they move from flower to flower whilst perched on the flower, constantly probing with their proboscis as they feed on the nectar from each flower.

Interestingly, the Danainae are not often photographed feeding on Ixora. Perhaps the Crows and Tigers prefer other flowering plants to the Ixoras? It would be an interesting subject to research how plants attract butterflies to their flowers, and why certain families or sub-families of butterflies are not attracted to certain flowers.

Lycaenidae species feeding on Ixora javanica.  Note their fine proboscis probing into the flower

Many species of the Lycaenidae have also been recorded on Ixora javanica flowers - one of which is exceedingly rare in Singapore - the Golden Royal (Pseudotajuria donatana donatana). A female was recorded feeding on Ixora some time in 2005. It was almost 10 years later in 2013, that another individual was photographed in the field.

Hesperiidae species on flowers of Ixora javanica

The Skippers also feed on the flowers of the Ixora javanica. It is interesting to observe as the species like the Hoary Palmer and Conjoined Swift, using their extra long proboscis to probe deep into the Ixora flower, almost like anglers "fly-fishing" with their long lines!

So there you have it, our sixth butterfly nectaring plant, the Javanese Ixora (Ixora javanica) and some examples of the butterflies that visit it to feed. So when you are out in our parks and gardens, take a closer look whenever you encounter the Javanese Ixora bushes, and you may be delighted by the variety of butterflies that are attracted to the flowers.

Text by Khew SK : Photos by Sunny Chir, Khew SK, Koh CH,  Loke PF, Horace Tan, Tan CP and Anthony Wong

References : 

The Concise Flora of Singapore : Hsuan Keng Singapore University Press, 1990
1001 Garden Plants in Singapore : Boo Chih Min, Kartini Omar-Hor and Ou-Yang Chow Lin, National Parks Board, 2nd Edition 2007
Plants in Tropical Cities : Boo Chih Min, Sharon Chew and Jean Yong, 2014
A Guide to the WildFlowers of Singapore : Foo Tok Shiew, Singapore Science Centre, 1985

Other Favourite Nectaring Plants in this series :

#1 : Snakeweed (Stachytarpheta indica)
#2 : Stringbush (Cordia cylindristachya)
#3 : Prickly Lantana (Lantana camara)
#4 : Bandicoot Berry (Leea indica)
#5 : Red Tree Shrub (Leea rubra)

14 February 2015

Life History of the Blue Nawab

Life History of the Blue Nawab (Polyura schreiber tisamenus)

Butterfly Biodata:
Genus: Polyura Billberg, 1820
Species: schreibers Linnaeus, 1758
Subspecies: tisamenus Fruhstorfer, 1911
Wingspan of Adult Butterfly: 60-80mm
Caterpillar Local Host Plants: Adenanthera pavonina (Fabaceae, common name: Red Saga), Nephelium lappaceum (Sapindaceae, common name: Rambutan), Acacia auriculiformis (Fabaceae, common name: Earleaf acacia), Ceiba pentandra (Malvaceae, common name: Silk-cotton Tree), Bruguiera cylindrica (Rhizophoraceae, common name: Bakau Putih).

A female Blue Nawab giving us a view of its upperside.

Physical Description of Adult Butterfly:
The forewing has a strongly arched costa, a pointed apex and a concave termen. The hindwing has a pair of short stubby tails, longer and more pointed in the female. On the upperside, the Blue Nawab is brownish black with a whitish median band, broadly edged in blue, stretching across both wings. The white band is broader in the female. On the underside, the Blue Nawab is silvery white and is marked with bluish and brownish bands and spots.

A male Blue Nawab giving us a view of its upperside.

Field Observations of Butterfly Behaviour:
Blue Nawab is moderately rare in Singapore. They can be found in urban parks, gardens, forested areas and mangrove wetlands. The adults are large-sized, heavy-bodies butterflies with rapid and strong flights. They have a habit of perching high at tree-top level and have also been observed to puddle on wet grounds, carrion and faeces.

Early Stages:
The early stages of the Blue Nawab have been locally observed to feed on leaves of five plants across different plant families. Of these, the Red Saga is most popularly utilized with regular sightings of caterpillars on young plants. The caterpillars feed on leaves of the host plants, and rest on the leaf upperside. The early instars rests on the midrib near the leaf tip where a silk bed has been spun. Larger caterpillars in later instars spin a silk mat across several leaves/leaflets (if the leaf or a leaflet is not large enough to accommodate the caterpillar) to create their "base camps" for rests between feeds.

Local host plant #1: Adenanthera pavonina (Red Saga).

Local host plant #2: Acacia auriculiformis.

The egg is laid singly on the upperside of a leaf/leaflet of the host plants. Each egg is yellow and spherical in shape, and its surface marked with barely distinguishable longitudinal ridges. The egg is rather large with a diameter of about 1.9mm.

Two views of an egg of the Blue Nawab.

Two views of a mature egg of the Blue Nawab. Note the head capsule being distinguishable through the egg shell.

The hatching event of a Blue Nawab caterpillar.

The egg takes about 4 days to hatch, and the newly hatched has a body length of about 5.5-6mm. The young caterpillar eats the entire egg shell as its first meal. Its body is initially golden brown but turning green a day or two later. It has a black/brownish head with 2 pairs of curved horns, the lower of which being shorter and more straight. There is also pair of pointed process at the posterior segment.

A sequence of three pics showing a newly caterpillar of the Blue Nawab eating its egg shell while its cephalic horns being unfurled concurrently.

Two views of a newly hatched Blue Nawab caterpillar, length: 5.5mm.

Two views of a 1st instar caterpillar, length: 8.5mm.

An early 1st instar caterpillar observed in the field.

After 5-7 days of feeding, the 1st instar caterpillar grows to a length of about 10mm. The caterpillar stays dormant in its base camp with the new head capsule growing progressively larger behind the current one. The caterpillar moults to the next instar about half a day later.

Two views of a late 1st instar caterpillar, dormant prior to its moult, length: 10mm.

The 2nd instar has green body. Its head capsule is now reddish brown and has proportionately longer horns than those in the 1st instar, reddish brown in colour). At the other end, the posterior segment is yellowish brown and squarish, with the two anal process proportionately shorter and positioned at the two corners of this segment. After 4.5-5 days in this instar, and having the body length increased to about 15mm, the caterpillar moults again.

Two views of a newly moulted 2nd instar caterpillar, length: 9mm.

Two views of a 2nd instar caterpillar, length: 13mm.

Two views of a late 2nd instar caterpillar, dormant prior to its moult, length: 15mm.

A 2nd instar Blue Nawab caterpillar resting on the upper surface of a Red Saga leaf in a western wasteland.

The head capsule of the 3rd instar caterpillar is pale beige brown initially; however all but the horns turn greenish (the horns) after a day or two. wide vertical streaks in dark brown. Some specimens might at this stage feature a small yellowish spot on the dorsum of the 3rd abdominal segment. This instar takes about 5 to 6 days to complete with body grown to about 23-26mm in length.

Two views of a 3rd instar caterpillar, early in this stage, length: 14mm.

Two views of a 3rd instar caterpillar, late in this stage, featuring the dorsal spot, length: 26mm.

Two views of another 3rd instar caterpillar, late in this stage, with the dorsal spot absent, length: 23mm.

A 3rd instar caterpillar found in the field, resting in its base camp on a Red Saga plant.

The head capsule of the 4th instar caterpillar is yellowish green with the horns red-tipped in most specimens. In this instar, the dorsal spot on the 3rd abdominal segment could be absent, occur as a tiny speck, a larger oval spot, and bright yellowish crescent mark (edged in black). The two anal processes are now minuscule in size and hardly distinguishable. This penultimate instar lasts a further 6-7 days with body length reaching about 34-37mm. In the last few days of the instar, pale green crescent marks start to appear on each body segment, giving us a hint of what the next instar will bring.

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

Two views of a 4th instar caterpillar, with the dorsal spot in the form of a tiny speck, length: 38mm.

Two views of a 4th instar caterpillar, with the dorsal spot being a prominent crescent mark, length: 38.5mm.

A 4th instar caterpillar found in the field, with the dorsal spot being oval in shape, resting in its base camp on a Red Saga plant.

The 5th instar caterpillar closely resembles the 4th instar caterpillar. The horns on the head capsule are observed to be broader than those in the 4th instar, and the amount of red shading they carry varies from specimen to specimen. The same variation in the dorsal spot on the 3rd abdominal segment can be seen in this instar. Some caterpillars without the dorsal spot in the 4th instar have been observed to possess the spot in the final instar. Another noticeable change is in the posterior segment where the golden brown shading seen in in earlier instars is now absent.

Three 5th instar caterpillars, showing variations in the dorsal spot on the 3rd abdominal segment.

Head capsules of 6 final instar Blue Nawab caterpillars, showing variations in coloration.

Two views of a 5th instar caterpillar, with crescentic mark late in this stage, length: 60mm.

A 5th instar caterpillar found in the field, resting in its base camp on a Red Saga plant.

The 5th instar lasts for 12-13 days typically, but might reach 16 days for some specimens. The body length could reach up to 60-65mm. Toward the end of this instar, the body gradually shortens in length. The fully grown caterpillar soon abandons its "base camp" and goes in hunt for a pupation site. Eventually the caterpillar comes to rest on a spot on the under surface of a stem. There it spins a silk pad to which it attaches its claspers (anal prolegs). The pre-pupatory larva then hangs vertically, typically with its body curled up.

A pre-pupa of the Blue Nawab in its curled up posture

The pupation event of a Blue Nawab caterpillar.

Pupation takes place a day later. The pupa suspends itself from the same silk pad but now with its cremaster. The pupa has a berry like appearance with its thick and cylindrically oval shape. It is green but streaked with abundant white, especially on the leading edge of the wing pads. The tip of the pupa, where the head is sited, is colored reddish/pinky brown. Length of pupa: 24-25mm.

Three views of a berry like pupa of the Blue Nawab.

The pupal period lasts for about 10.5 to 11 days, and the pupa turns dark to reddish brown the night before eclosion. The white median band on the forewings also become visible through the pupal skin at this stage.

Three views of a mature pupa of the Blue Nawab.

Eclosion takes place the next day. The pupal case first cracks open with the adult butterfly making its way out. It quickly turns around and perches on the underside of the pupal case to "dry" and expand its wings. A few hours later, the adult butterfly makes the first flight of its life.

The eclosion event of a Blue Nawab butterfly.

A newly eclosed Blue Nawab clinging on to its pupal case.

A newly eclosed Blue Nawab.

  • [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 Lemon Tea Yi Kai, Tan Ben Jin, Simon Sng, Koh Cher Hern, Khew SK and Horace Tan