Life History of the Pea Blue

Life History of the Pea Blue (Lampides boeticus)



Butterfly Biodata:
Genus: Lampides Hübner, 1819
Species: boeticus Linnaeus, 1767
Wingspan of Adult Butterfly: 22mm
Caterpillar Local Host Plants: Crotalaria mucronata (Leguminosae), Crotalaria retusa (Leguminosae)


Uppersides of Pea Blue: female (left); male (right).

Physical Description of Adult Butterfly:

Above, the male is dull purple with two black tornal spots on each hindwing. The female is brown with wing bases pale shining blue. Faint marginal spots and two tornal spots can be found on each hindwing of the female. Beneath, both sexes is buff in colour and have markings comprising white transverse fasciae in the distal halves of the wings. The black tornal spots in spaces 1b and 2 of each hindwing have metallic scalings and are orange-crowned. Each hindwing has a slender white-tipped filamentous tail at the end of vein 2.

An adult Pea Blue resting on a perch in Pulau Ubin (a small granite island).


A male Pea Blue visiting a flower in a wasteland near the Dairy Farm Nature Park.


Another adult Pea Blue visiting flowers.

Field Observations of Butterfly Behaviour:

The Pea Blue is one of the most widely distributed lycaenids in the world with its occurrence spanning Europe, Africa, Asia and Australia. Due to its utilization of pea spp. as host plants, titis considered as a pest of pea crops in certain places. In Singapore, the Pea Blue can be found in various wasteland and coastal areas on both the main island and offshore islands where its local host plants, Crotalaria spp., are growing. Development of these patches of lands for housing and commercial purposes threaten to shrink its local population. Typically the adults can be observed whole year round, and are typically found flying in the vicinity of its host plants, visiting flowers and puddling on wet grounds. The adults are strong flyers with a jerky and rapid flight.

Early Stages:

The local host plant, Crotalaria mucronata, is shrubby with erect growth. The leaves are 3-foliolate with oval-obovate leaflets. The papilionaceous flowers occur in inflorescences and are yellow with reddish or purplish stripes. Seed pods are initially green but turning brown when mature.The other host plant, Crotalaria retusa, is 1-folioate and its flowers do not have reddish/purplish stripes. The first two instars of the Pea Blue have the habit of boring into flower buds and eating the flower parts contained within. The larger 3rd and final instar caterpillars will move on to eat the developing seeds within seed pods.

Host plants: Crotalaria mucronata (left); Crotalaria retusa (right).


Flower buds: Crotalaria mucronata (left); Crotalaria retusa (right).


Seed pods: Crotalaria mucronata (left); Crotalaria retusa (right).

Eggs of Pea Blue are laid on young shoots, flower buds or leaves of the host plant. The small egg is disc-like (about 0.5mm in diameter) with a depressed micropylar. When freshly laid, the egg is yellowish green. The color soon decolorizes to light green within the next few hours, and then to white as it matures. The surface is covered with a reticulated pattern of intersecting ridges, and the intersections are prominently raised for those lying on the outer rim of the egg.


A mating pair of the Pea Blue.


A female Pea Blue laying an egg on a young flower bud of Crotalaria mucronata.


Two views of an egg of the Pea Blue. Diameter: 0.5mm.

Each egg takes 2-2.5 days to hatch. The young caterpillar emerges after nibbling away sufficiently large portion of the egg shell. Measured at a length of about 0.8mm to 0.9mm, its pale yellow body is cylindrical in shape, sporting moderately long fine setae, a black head capsule and a dark prothoracic shield.


Top: a newly hatched caterpillar about to bore into a flower bud, length: 0.9mm.
Bottom: 1-day old caterpillar, length: 1.1mm.

The newly hatched makes its way to a flower bud and starts to bore into it. It stays within the flower bud and feeds on the flower parts. After 1.5 to 2 days of growth, it reaches about 2mm in length, and faint reddish brown bands appear dorsally and laterally. The moult to the 2nd instar typically takes place within the flower bud.


1st instar caterpillars, late in this stage, length: 2mm.
The body was covered with pollens as both had stayed within flower buds moments earlier.

Covered with numerous dark setae, the body of the 2nd instar caterpillar is pale yellowish brown in base color with reddish brown bands running dorsally and laterally. The head capsule is still black in colour with a dark-colored prothoracic shield. The body is now more woodlouse-like in shape. The 2nd instar caterpillar maintains the habit of boring into flower buds and feeding within them. The growth in this stage brings the caterpillar to a length of about 3.5-4mm, and after about 2 days in this stage, it moults again.


Two views of a 2nd instar caterpillar, early in this stage, length: 1.8mm.


Two views of a 2nd instar caterpillar, lengths: 2.5mm.

The 3rd instar caterpillar has numerous short and fine body setae. A faint dorsal band and many obligue lateral stripes are present. As with many lycaenids, Pea Blue exhibits chromatic polymorphism in larval color with the various body markings in green, reddish brown or intermediate coloration. The head capsule is still black but the prothoracic shield has decolorized to the body base color. Both the dorsal nectary organ and the tentacular organs are discernible in this instar. The caterpillar also migrate from eating flower parts to eating developing seeds within seed pods. The 3rd instar takes 2.5-3 days to complete with the body length reaching about 7.5-8.0mm before the next moult.


Two views of a 3rd instar caterpillar. green form, length: 6.5mm.


3rd instar caterpillars. red and intermediate forms, length: 8mm.

The 4th (and final) instar caterpillar is similar in appearance to the 3rd instar caterpillar with one main difference being the change of head capsule from black to pale yellowish brown, and the spiracles from black to pale yellow or white. The nectary organs are rather prominent in this instar as well.


4th instar caterpillars of two colour forms. early in this stage, length: 8mm.


4th instar caterpillars, late in this stage, lengths: 12mm (top); 14mm (bottom).
Both are eating seeds in seed pod.

After 3.5-4 days of growth and reaching a maximum length of around 14-15mm in the final instar, the body of the caterpillar gradually shrinks. The caterpillar ceases eating and wanders around for a pupation site. All bred specimens chose to enter their pre-pupatory phase on a spot of the leaf surface within a pile of withered leaves.. At the chosen site, the caterpillar readies itself for pupation by spinning a silk girdle and a silk pad. In the wild, some caterpillars also choose to pupate within seed pods.


Two views of an immobile pre-pupatory larva of the Pea Blue, red form.
The silk girdle can be easily seen.


Two views of an immobile pre-pupatory larva of the Pea Blue, green form.

Pupation takes place after one day of the pre-pupal stage. The hairy pupa has the typical lycaenid shape, beige in base colour with many black to dark brown patches on the pupal surface. Unlike most other lycaenid pupae, the pupa of Pea Blue does not secure itself with cremastral hooks, and its posterier end does not angle downwards. The pupa has a length of about 9-11mm.


Two views of a pupa of the Pea Blue, length: 11mm

Five days later, the pupa becomes darkened in color signaling the imminent emergence of the adult. Patches of blue can be seen in the wing pads through the now transparent pupa skin. The next day the adult butterfly emerges from the mature pupa.


Two views of a mature pupa of the Pea Blue.

Early stages of the Pea Blue.

Eclosion of a female Pea Blue.

A newly eclosed Pea Blue drying its wings near its empty pupal case.


A newly eclosed Pea Blue ready to take its first flight.


References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
• A Photographic Monograph on Hong Kong Butterflies, Volumes 1-3, Hong Kong Lepidopterists' Society.

Text by Horace Tan, Photos by Goh Lai Chong, Bobby Mun, Khew S K and Horace Tan

Official Opening of Dairy Farm Nature Park

Official Opening of the Dairy Farm Nature Park
5 Sep 2009


A view of the Dairy Farm Nature Park Visitor Centre

Yesterday, 5 Sep 2009, saw the official opening of yet another environmental offering from the National Parks Board in Singapore. With the opening of the $5.7M Dairy Farm Nature Park and the Wallace Education Centre, Singaporean nature buffs can now enjoy another gateway to the Bukit Timah Nature Reserve via the 63 Ha Dairy Farm Nature Park.

Located on the northern boundary of the Bukit Timah Nature Reserve, and off Dairy Farm Road, the Visitor Centre of the Dairy Farm Nature Park boasts a small sheltered gathering area and an open landscaped toilet for users of the park. A new carpark with a relatively good number of parking lots will delight drivers who used to park at the Hindhede area. A second carpark off Upper Bukit Timah Road near the MOE Adventure Camp also offers users of the Bukit Timah Nature Reserves another alternative location to start off their nature walks.

Minister Mah delivering his speech

The Dairy Farm Nature Reserve & Wallace Education Centre was officially opened by Minister for National Development, Mr Mah Bow Tan. Received by a sizeable crowd of nature enthusiasts and school children, Minister shared the many new parks and nature offerings from the National Parks Board to the enthused crowd. Amongst the projects will be an interesting concept of creating a new 50m wide nature link between the Bukit Timah Nature Reserve and the Central Catchment Nature Reserve over the Bukit Timah Expressway (BKE). The bridge, 50m wide at its narrowest point and planted with dense trees resembling a forest habitat, could help populations of animals like the critically-endangered banded leaf monkey to recover.



The Wallace Education Centre also serves as a exhibition and learning facility for nature enthusiasts to meet and share their knowledge with others. Converted from an old dairy farm, the building houses two big exhibition halls and some meeting facilities. The building is a nice example of architectural conservation and adaptive re-use of a utilitarian agricultural building.

The spanking new Wallace Education Centre at Dairy Farm Nature Park

At the exhibition on opening day was a chronological history of the area, and some nature dioramas featuring the flora and fauna of the Dairy Farm area. An ecological learning lab converted from an old cowshed offers programmes developed with partners Raffles Girls' School and the National University of Singapore, and sponsored by GlaxoSmith-Kline.

On the school side of the exhibition were booths featuring recycling and nature appreciation from various school participants. One of the booths also featured butterfly appreciation and conservation, and I was amused to note that many of the photos from the Raffles Girls School exhibit were taken from ButterflyCircle members' works (probably without permission! :-p) Anyway, it's for a good cause and our works were used to enhance the girls' mission to promote butterfly conservation.

The Dairy Farm Nature Park also features a number of well-marked trails, one of which celebrates the renowned 19th century naturalist, Alfred Russel Wallace who did a lot of work walking the trails and collecting at Bukit Timah Hill and the surrounding area during his time in Singapore.

A special trail is also dedicated to Wallace. Many trails also link to the Bukit Timah Nature Reserve and the nearby Zhenghua Park.

It was a nice event, and I had the opportunity to meet old friends from MND, NParks, NUS School of Design and Environment, nature enthusiasts and also to make new acquaintances with like-minded people in the nature community in Singapore.

A lost hiker checks out the map of Dairy Farm Nature Park

With the opening of this new facility, nature enthusiasts now have better accessibility and parking amenities to another area of the Bukit Timah Nature Reserve, and hopefully, alleviate the over-crowded conditions at the Hindhede Road side of the Nature Reserve. ButterflyCircle members now also have another location to conduct butterfly surveys and photography, and perhaps soon add more species to the Singapore Checklist!

Text & Photos by Khew SK

Additional News : NParks opens new Dairy Farm Nature Park to protect biodiversity

Butterfly of the Month - September 2009

Butterfly of the Month - September 2009

The Archduke (Lexias pardalis dirteana)

This month we feature another species that exhibits sexual dimorphism - the Archduke. This species is seasonally common in Singapore's nature reserves, and found mainly on shaded forest paths and amongst undergrowth amongst tall trees. The species is seldom seen in open sunny areas, and is a forest-dependent species.

The Archduke belongs to the genus Lexias which consists of rather large, robust and fast flying butterflies. The Archduke is the commonest species of the genus found in Singapore, often encountered feeding on rotting fruits and other organic matter amongst forest litter.

A female Archduke forages on the ground for nutrients

The males are dark velvety black above with a broad blue distal border on the hindwing, which is continued narrowly along the termen of the forewing. The underside is deep ochreous brown with yellow spots. The larger female is dark brown above, and profusely spotted with yellow above and white on the undersides. The underside of the hindwing is pale grayish green. The apical portion of the antennal club is orange in both sexes and this distinguishes this species from the closely-related and very similar Black-Tipped Archduke (Lexias dirtea merguia).

The female Archduke is a good example of adaptation by natural selection to camouflage itself better to escape predators like birds. Its dark brown and yellow-spotted wings render it almost invisible as it feeds on the forest floor with dappled sunlight. As many observers will attest, the Archdukes tend to fly rapidly from underfoot when disturbed, as one walks towards their favourite feeding spots along damp forest paths littered with dead leaves and twigs. As they land to feed again, they blend in well with their surroundings, particularly more so with the female.

The robust body of the Archduke is an indication of the powerful flight that it is capable of. Once alarmed, the Archduke takes off rapidly with a few wingbeats, and glides amongst the undergrowth. The species is a relatively large butterfly, attaining wingspans of up to 150mm in the larger female.

The caterpillar has a rather unique appearance with branched spines that allows it to camouflage itself well on the upper surface of its host plant, Cratoxylum pruriflorum. The branched spines terminate with attractive orange-and-black tips that make the caterpillar appear unfriendly. However, it is not poisonous at all, and can be touched without any danger.

An Archduke's "baby photo"

In Singapore, there are two lookalikes to the Archduke and may be confused with this species. They are the Black-Tipped Archduke (Lexias dirtea merguia) which has males and females correspondingly similar to the Archduke, except that the antennae of the latter species is black instead of orange. The other species is the Yellow Archduke (Lexias canescens pardalina) in which both the sexes resemble the female of the Archduke, but are smaller in size. All three prefer shaded habitats in the forest understorey in the nature reserves of Singapore.

Text by Khew SK ; Photos by James Foong & Khew SK

Life History of the Blue Spotted Crow

Life History of the Blue Spotted Crow (Euploea midamus singapura)

Butterfly Biodata:
Genus: Euploea Fabricius, 1807
Species: midamus Linnaeus, 1758
Subspecies: singapura Moore, 1883
Wingspan of Adult Butterfly: 80mm
Caterpillar Local Host Plant: A plant in the Apocynaceae family, specific ID to be determined.

Physical Description of Adult Butterfly:
Above, the wings are blackish brown, usually without the blue sheen seen in other Euploea species. The termens are slightly crenulate and there are marginal and submarginal series of white spots, with submarginal spots in spaces 6, 7 and 8 rather large and elongated. on the forewings. There is also a white spot in the cell and a few distal spots. Underneath, the markings resemble those on the upperside. The male has a small and narrow brand in space 1b on the forewing and a pale yellowish scent patch in the cell area on the hindwing.



A Blue Spotted Crow feasting on the flowers of a Syzygium plant in the nature reserve.


A Blue Spotted Crow puddling on the cement floor of a shelter hut in the nature reserve.

Field Observations of Butterfly Behaviour:
This Singapore subspecies of the Blue Spotted Crow is uncommon in Singapore, and is rarely seen. Sightings of the slow flying adults includes individuals or small groups visiting flowers and puddling. One rare occasions, several adults could be seen flying around shelter huts built alongside trails in the catchment area, with some even puddling on the cement floor of the shelters. Although mostly confined to the nature reserves, some individuals have also been observed in housing estates.

Early Stages:
Elsewhere in its range of occurrence, host plants recorded for this species are mainly members of the Apocynaceae family, examples are Strophanthus divariatus and S. divergens in Hong Kong, S. dichotomus, Nerium oleander and Roupellia sp. in Java. As for the singapura subspecies of the Blue Spotted Crow, thus far only one host plant, which has opposite leaves and pale yellowish sap (lactiferous), has been located in the local nature reserves. The caterpillars of Blue Spotted Crow feed on the young and tender leaves in its early instars but move on to the more mature and larger leaves in the later instars.

Local host plant for the Blue Spotted Crow found in the nature reserve.

The eggs of the Blue Spotted Crow are laid singly on the young leaves of the host plant, typically on the underside. The yellow eggs are tall (about 1.8mm in height) and somewhat cylindrical (diameter: 1mm) with a rounded top. The egg surface is ribbed.

A mother Blue Spotted Crow laying egg on a young leaf of the host plant.

Left: fresh egg; Right: mature egg. Note the black head is visible in the mature egg.

The egg takes about 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 2.3mm. Its cylindrical body is pale yellowish. The large head capsule is black in color. A pair of short and inconspicuous protuberances can be found on the dorsum of each of the following four segments: 2nd and 3rd thoracic segments, 2nd and 8th abdominal segments.


Two views of a newly hatched caterpillar eating the egg shell, length: 2.3mm.

Once the newly hatched moves on to feed on the young leaves over the next few hours, its body starts to take on a green undertone. The growth is rather rapid with the body length doubling in one day, and after just 1 to 1.5 days from hatching, it moults to the 2nd instar. Towards the final hours of the 1st instar, the 8 protuberances turned orangy brown and become more marked in appearance. This period of growth also brings along blackened ends for all 8 pairs of legs.


Two views of 1st instar caterpillar, late in this stage, length:5.5mm.

The body of the 2nd instar caterpillar is again yellowish orange with a green undertone. The most obvious change is the lengthening of the 8 protuberances to short processes, each of which is almost entirely dark brown to black. There are two small brown spots on the dorsum of the prothorax, and one large black patch on the posterior end of the body. This instar lasts only 1 to 1.5 days with the body length reaching 11mm before the moult to the 3rd instar.


Two views of a 2nd instar caterpillar, late in this stage, length: 11mm

The 3rd instar caterpillar is similar in appearance to the 2nd instar caterpillar with the only change being the proportionally longer processes. This instar takes about 1-1.5 days to complete with body length reaching about 16-17mm.


3rd instar caterpillar, newly moulted, length: 6mm


3rd instar caterpillar, late in this stage. .Lengths: 9mm (top) and 11mm (bottom).

Retaining very much the same body features from the earlier two instars, the 4th instar caterpillar distinguishes itself in having proportionally longer processes which have the tendency to flex forward with ends slightly curved. This instar lasts 1.5 to 2 days with the body length reaching about 27mm.


Two views of a 4th instar caterpillar, late in this stage, length: 27mm.

The 5th and final instar brings along a slightly more dramatic change in appearance. Now the 8 processes have become very long and filamentous, with the tapering ends having a strong tendency of twirling. The spiracles have also become more prominently marked in large black spots.


A newly moulted 5th instar caterpillar, with its exuvia trailing behind.

One surprising and exciting find during this breeding exercise is the discovery of adenosma being present in this Euploea species, a first for the Danainae subfamily. The Blue Spotted Crow caterpillars, at least for the singapura subspecies, readily flash their adenosma when they are disturbed. This yellow-colored adenosma could be easily observed in both the 4th and 5th instars. Refer to the pictures and youtube clip below for an illustration of this adenoma, which is located just ahead of the 1st pair of the thoracic legs. As can be seen in the pictures, the caterpillars of Blue Spotted Crow also adopt the characteristic on-guard posture with the anterior body arched and the head tucked beneath the thorax.

The on-guard stance of an early 5th instar caterpillar, length: 30mm.

The same caterpillar as in the earlier picture, this time with its adenosma everted.

The eversion of the adenosma of a 4th instar caterpillar of the Blue Spotted Crow.

Two views of a 5th instar caterpillar, length: 40mm.

The 5th instar lasts for 4-5 days, and the body length reaches up to 47mm. On the last day, the caterpillar ceases feeding, and its body becomes shortened but with no change in body color. 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. Within the few hours prior to pupation, the caterpillar gradually relaxes and lengthens to a straight posture. Waves of contraction soon travel from the the rear end to the head until the pupation event kicks in.

Pre-pupatory larva. Left: early stage; Right: late stage with the onset of pupation only minutes away.

The pupation event of a Blue Spotted Crow caterpillar (shown at 10x speed).

Pupation takes place 0.5 days after the caterpillar assumes the hanging posture. Typical of the pupae within the Nymphalidae family, the pupa of the Blue Spotted Crow suspends itself from the silk pad with no supporting silk girdle. Initially, the pupa is bright yellowish orange, but the surface gradually takes on a silvery metalic glitter about a day later. The pupa is rather rotund, and has a few black spots and dark brown patches on the dorsum. Length of pupae: 20-22mm.


Three views of a fresh pupa of the Blue Spotted Crow.

Three views of a shining pupa of the Blue Spotted Crow.


Three views of a mature pupa of the Blue Spotted Crow.
The prominent submarginal spots can be seen in the wing pad area.

After about 6 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The spots on the forewing upperside also become discernible. The following day, the adult butterfly emerges from the pupal case. It then perches nearby to expand and dry its wings before taking its first flight.

A newly eclosed Blue Spotted Crow drying its wings on its pupal case.

A newly eclosed Blue Spotted Crow.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
• A Photographic Monograph on Hong Kong Butterflies, Volume 1, Hong Kong Lepidopterists' Society.
  
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

Text by Horace Tan, Photos by Anthony Wong, Henry Koh and Horace Tan