Life History of the Common Hedge Blue

Life History of the Common Hedge Blue (Acytolepis puspa lambi)

Butterfly Biodata:
Genus: Acytolepis Toxopeus, 1927
Species: puspa Horsfield, 1828
Sub-species: lambi Distant, 1992
Wingspan of Adult Butterfly: 25-30mm
Caterpillar Local Host Plants: Combretum sundaicum (Combretaceae), Ventilago maingayi (Rhamnaceae), Prunus polystachya (Rosaceae), Rosa hybrids (Rosaceae).

Physical Description of Adult Butterfly:

On the upperside, the male is shining blue with a black border widening to about 2mm at the forewing apex; and the female is pale shining blue with very broad black borders on both wings. On the underside, the wings are greyish white and have the usual black marginal spots and post-discal bands on both wings. In addition, each hindwing features several black spots in the basal half and one small black spot at the extreme base of space 7.

A sunbathing male Common Hedge Blue showing us its wing upperside.

Field Observations of Butterfly Behaviour:

This species is moderately common in Singapore. It is usually found in forested areas of the nature reserves but occasional sightings have been made in urban parks and gardens. They have been observed to sunbathe with open wings and puddle on damp forest paths.

Early Stages:

Four local host plants have been recorded so far for the Common Hedge Blue. Of these, Combretum sundaicum and Prunus polystachya can be found in many parts of the central catchment reserve. Caterpillars of the Common Hedge Blue feed on young leaves of the host plants and are typically found in the company of attending ants.

Local host plant #1: Combretum sundaicum.

Local host plant #2: Ventilago maingayi.

Local host plant #3: Prunus polystachya.

Eggs of the Common Hedge Blue are laid singly on a young leaf, a young shoot, or the flower buds of the host plant. The small pale green egg is discoid in shape and about 0.6mm in diameter, its surface covered with a reticulated pattern of intersecting ridges. The micropylar sits atop in the middle of the top surface.

A female Common Hedge Blue laying an egg on the underside of a young leaf of Combretum sundaicum.

A female Common Hedge Blue laying an egg on the flower bud of a rose plant.

An egg of the Common Hedge Blue.

The egg takes 3 days to hatch. The young caterpillar emerges after nibbling away sufficiently large portion of the egg shell. Measured at a length of about 1mm, its pale yellowish body is cylindrical in shape, sporting long fine setae (hair) dorso-laterally and laterally. It has a pale yellowish brown head capsule. The newly hatched feeds on the lamina of a young leaf. After about 2-3 days of growth and reaching a length of about 2mm, the caterpillar moults to the next instar.

Two views of a newly hatched caterpillar, length: 1mm.

Two views of a 1st instar caterpillar, early in this stage, length: 1.25mm.

A 1st instar caterpillar, late in this stage, length: 1.9mm.

The body of the 2nd instar caterpillar is covered with numerous short and whitish setae. Rows of longer white setae can be found dorsally and laterally. The body is pale yellowish brown to pale yellowish green. The prothoracic shield has the same coloration as the body base colour and thus indistinct. Meanwhile, the head capsule is still pale yellowish brown. This instar lasts about 3-4 days with the body length reaches up to 4mm.

Two views of a 2nd instar caterpillar, early in this stage, length: 2.9mm.

Two views of a 2nd instar caterpillar, late in this stage, length: 4mm.

Caterpillars of the Common Hedge Blue with ants in attendance on a leaf of Combretum sundaicum. Can you spot the three caterpillars?

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely in having numerous short and fine setae all over the body. Short oblique whitish stripes are present on the body dorso-laterally. Their arrangement on the sides of the dorsum gives the impression of yellowish green dorsal band being present. Both the dorsal nectary organ (on the 7th abdominal segment) and tentacular organs (on the 8th abdominal segment) are now easily observed. The 3rd instar takes 3-4 days to complete with the body length reaching about 7-8mm.

Two views of a newly moulted 3rd instar caterpillar, eating its exuvia, length: 4mm.

Two views of a 3rd instar caterpillar, length: 4.5mm.

Two views of a late 3rd instar caterpillar, dormant prior to its moult, length: 6mm.

A caterpillar of the Common Hedge Blue with ants in attendance on a young shoot of Prunus polystachya.

The 4th (and final) instar caterpillar bears cose resemblance to its former self in the 3rd instar. The lateral oblique whitish markings and the dorsal band are more prominent in this instar. Depending on the coloration of the leaf it feeds on, the caterpillar could come in a pale green form, a pale yellowish brown form or a reddish brown form. The dorsal nectary organ is easily observed as a paler elliptical patch on the 7th abdominal segment.

Two 4th instar caterpillars, brown and green forms, length: 8mm.

Two views of another 4th instar caterpillar, length: 11mm.

Two views of yet another 4th instar caterpillar, reddish brown form, on young leaves of Ventilago maingayi, length: 12mm.

After about 4-5 days of growth and reaching a maximum length of around 14mm in the final instar, the body of the caterpillar gradually shrinks and decolorises. The caterpillar typically chooses to enter their pre-pupatory phase in tight pockets of space between leaves in leaf litter. At the chosen site, the caterpillar readies itself for pupation by spinning a silk girdle and a silk pad. The caterpillar secures itself to the silk pad via claspers at its posterior end.

Two early pre-pupae of the Common Hedge Blue.

Two views of a pre-pupa of the Common Hedge Blue.

Pupation takes place after one day of the pre-pupal stage. The pupa has the typical lycaenid shape. It is pale yellowish brown in base color with a fair number of brown and black specks of various sizes. The pupa has a length of about 8-9mm.

Two views of a pupa of the Common Hedge Blue.

Eclosion takes place after 5-6 days in the pupal stage. The mature pupa gradually darkens in colour the day before. Bluish patches on forewing upperside become clearly visible in the wing pads of the mature pupa, and the extent of blue coloration will now tell us the sex of the soon to emerge adult.

Two views of a mature pupa of a male Common Hedge Blue.

Two views of a mature pupa of a female Common Hedge Blue

References:

• [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 Jonathan Soong, Koh Cher Hern, Cai Jin Huang, Anthony Wong, Chng CK, Loke PY and Horace Tan

A New Discovery in 2015!

A New Discovery in 2015!
The Common Yeoman (Cirrochroa tyche rotundata)


The Common Yeoman, a new addition to the Singapore Checklist

It started with a couple of shots that were sent to my WhatsApp account on my mobile phone on 10 Jun 2015. The photos were from Zhou Boyi, a Manager at the National Biodiversity Centre Div of NParks, who wanted to know if he had shot the recently discovered Malay Yeoman (Cirrochroa emalea emalea). Boyi was recording shots of butterflies on the new smartphone app known as SGBioAtlas developed by NParks.

Zhou Boyi's first shots of the newly-discovered Common Yeoman in Singapore

However, the butterfly that he encountered did not exactly match those photos of the Malay Yeoman on the SGBioAtlas, and he was curious if he got the ID of the butterfly correct. A quick look at his shots on my mobile phone indicated that what Boyi shot was indeed not the Malay Yeoman, but another close relative in the same genus Cirrochroa.

A Common Yeoman puddling in Singapore

This was the Common Yeoman (Cirrochroa tyche rotundata), a species that has not been recorded in Singapore before by the early authors. After establishing the last-seen location where Boyi shot the butterfly, ButterflyCircle members went to the urban garden to check out if the species was still around so that we could take more shots of this new discovery. Coincidentally, ButterflyCircle members also discovered another orange-coloured species, the Vagrant (Vagrans sinha sinha) in 2013, at another urban gardens in Singapore.

To our surprise, we discovered a small colony of the Common Yeoman! Earlier records of new discoveries and re-discoveries in Singapore, where individuals were reliably photographed, were either seasonal or migratory individuals chanced upon by butterfly enthusiasts. For these species, only one or two sightings were made, and many were not seen again. However, the presence of the colony of the Common Yeoman suggests that this species could have been successfully breeding in Singapore for some time already, before it was spotted.

A Common Yeoman perched on a leaf

At the location where it was first discovered by Boyi, we spotted at least half a dozen individuals and even a female ovipositing on its host plant. It is an active butterfly, flying restlessly and rarely stopping to rest, reminiscent of the common Leopard (Phalanta phalantha phalantha) - flapping and turning with half-opened wings even when at rest.  When actively fluttering around, it can tire even the most determined of photographers with its unceasing skittish flying behaviour!

After some time of patient waiting, we spotted a puddling male Common Yeoman that was cooperative enough for us to photograph it. It appeared to be a recently-eclosed individual, from its bright colours and pristine wings. In the meantime, several other females and males were spotted fluttering around the shrubbery, making only momentary stops to rest.

A Common Yeoman shot in Panti Forest Reserve, Johor

The Common Yeoman can be found in West Malaysia, and we have photographed it at the Panti Forest Reserve in southeast Johor, a mere 40-50 km drive from Singapore. There, it demonstrated the same active and skittish behaviour and was also photographed puddling on damp footpaths in forested area.

Another Common Yeoman shot in the Kuala Kangsar area (Perak state) in Malaysia

A quick comparison of the photographs of the Common Yeoman shot in Singapore showed that it matched quite closely with those shot in West Malaysia, in particular those from Panti Forest. This would be the Malaysian subspecies rotundata. The Common Yeoman is fulvous orange above, with a black distal margin or with black sinuate marginal and submarginal spots and lines. The Common Yeoman does not have the broad black apical area on the forewing like the other related species.

A mating pair of the Common Yeoman, shot in Panti Forest Reserve in Johor

The underside is paler with a silvery white or whitish transverse band across both wings. In the Common Yeoman, this pale discal band is narrow and generally uniform in width across both wings, whilst the band widens towards the costa of the forewing in the other related species.

A Common Yeoman puddling on the muddy forest floor at Panti Forest Reserve, Johor

The butterflies of the genus Cirrochroa are known to show migratory tendencies. They have been described as "rapid in flight but occasionally found at moist spots on the roadside." [Butterflies of the Malay Peninsula by Corbet & Pendlebury 4th Edition, pg 153]


A Common Yeoman perched on a leaf.  Shot in Singapore

How did the Common Yeoman appear in Singapore? Did it migrate naturally across the Straits of Johor, when the prevailing winds were in its favour? Or did the caterpillars or pupae of this species stow away on plants that came into Singapore? Many theories may be expounded as to how this species first came to Singapore, but we will never know for certain.

A Common Yeoman perched on a leaf.  Shot in Singapore.

That a colony of the butterflies has now established themselves in Singapore is now certain. For how long this will sustain, we will have to observe closely. Would the lack of genetic diversity wipe out the species after a few generations due to inbreeding? Or will it thrive and be a resident species in Singapore and adding to the biodiversity of our butterfly fauna? Its geographical range is described as "occurring throughout Sundaland", but why was it not earlier recorded in Singapore?

As with many mysterious phenomena occurring in our natural world, there are more questions than there are answers. But we will record the Common Yeoman as species #318 in the Singapore Butterfly Checklist, and observe whether the species will continue to flourish on our little island in the sun.

Text by Khew SK : Photos by Goh LC, Federick Ho, Khew SK, Horace Tan and Mark Wong

References : 

[C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society, 1992.

Special thanks and credit to Zhou Boyi of the National Parks Board for the discovery of this new butterfly species to Singapore.

Life History of the Grey Pansy

Life History of the Grey Pansy (Junonia atlites atlites)

Butterfly Biodata:
Genus: Junonia Hübner, 1819
Species: atlites Linnaeus, 1763
Subspecies: atlites Linnaeus, 1763
Wingspan of Adult Butterfly: 55-60mm
Caterpillar Local Host Plants: Nelsonia canescens (Acanthaceae), Hygrophila spp. (Acanthaceae), Limnophila villosa (Plantaginaceae)

Physical Description of Adult Butterfly:
On the upperside, the wings are pale greyish buff and distinctly marked with dark brown discal and submarginal lines. Post-discal series of eye-spots, some of which are divided into an outer black half and an inner orange half, are found on both forewing and hindwing. On the underside, the wings are marked as per above but all markings are much paler.

Field Observations of Butterfly Behaviour:
This species is the rarest of the four Pansy species in Singapore. It makes seasonal and localized appearances, and can be found in nature reserves and coastal parks. It flies in the usual gliding manner of the Junonia spp. Under sunny condition, the adults have a habit of opening their wings wide to sunbathe while resting on a perch.

Early Stages:
In Singapore, two host plants have been recorded so far. They are Nelsonia canescens and Limnophila villosa, belonging to the Acanthaceae and Plantaginaceae families respectively. Both occur as herbs, carpeting the ground wherever they inhabit. The caterpillars of the Grey Pansy feed on leaves of the host plants.

Local host plant: Nelsonia canescens.

The eggs of the Grey Pansy are laid singly on the leaves or shoots of the host plants. The greenish egg is somewhat globular in shape but with a flat top. A number of raised ridges run from this top end to the base of the egg. Each egg has a diameter of about 0.6-0.7mm.

Two views of an egg of the Grey Pansy. Diameter: 0.75mm.

A maturing egg of the Grey Pansy.

The egg takes about 3 days to hatch. The young caterpillar emerges by eating away part of the egg shell, and then proceeds to eat the rest of the egg shell from the outside. The initial length of the newly hatched is about 1.3mm. The cylindrical and yellowish orange body is covered with many small tubercles. Long dark setae emanate from these tubercles. The head capsule is black entirely. Once it starts to devour leaf lamina, the 1st instar caterpillar takes on a yellowis green appearance. After reaching about 3mm in 2-3 days, the caterpillar moults to the 2nd instar.

Two views of a newly hatched caterpillar eating its egg shell, length: 1.3mm.

Two views of a 1st instar caterpillar, length: 2.5mm.

The body of the 2nd instar caterpillar is pale brown. Moderately long and branched brownish processes run along the length of the body. Fine setae emanate from these processes and from other small tubercles on the body surface. The head capsule is black. This instar lasts about 2-2.5 days with the body length reaching about 5mm.

Two views of a 2nd instar caterpillar, length: 4.5mm

A late 2nd instar caterpillar, dormant prior to its moult, length: 5mm.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely, except for proportionately longer dorso-lateral and lateral processes. This instar takes about 2 days to complete with body length reaching about 9.5mm.

Two views of a 3rd instar caterpillar, length: 7mm.

The 4th instar caterpillar closely resembles the 3rd instar caterpillar, except for the proportionately longer processes and the change of the body colour to a much darker shade of brown. This instar lasts about 3 days with the body length reaching up to about 16mm.

Two views of a 4th instar caterpillar, early in this stage, length: 10mm.

Two views of a 4th instar caterpillar, late in this stage, length: 15.5mm.

The 5th (and penultimate) instar caterpillar is almost black to the naked eyes. One discernible difference is the presence of a dense set of moderately long fine setae covering the entire body surface. The black head capsule also takes on small orange-coloured patches. This instar lasts for about 3 days, and the body length reaches up to 24mm.

Two views of a 5th instar caterpillar, early in this stage, length: 16mm.

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

The 6th (and final) instar caterpillar is similar to the 5th instar caterpillar but has an even denser carpet of whitish fine setae on the body surface. A yellowish-orange band is present laterally, running just below the spiracles. The head capsule is black with its upper quarter in orange.

A 6th instar caterpillar, length: 26mm.

A 6th instar caterpillar, length: 35mm.

The 6th instar lasts for 4-5 days, and the body length reaches up to 45mm. At the end of the 6th instar, the caterpillar ceases feeding and wanders around. Eventually it stops at a spot on the underside of a leaf, petiole, young shoot/stem and spins a silk pad from which it hangs vertically to take on the pre-pupatory pose.

A pre-pupa of the Grey Pansy.

Pupation takes place about 0.5 days later. The pupa suspends itself from the silk pad with no supporting silk girdle. It is entirely greyish brown with a series of dorso-lateral pairs of short and pointed processes, one pair to each segment. The dorsum is sharply raised at the mesothorax. Length of pupae: 17-19mm.

Two views of a pupa of the Grey Pansy.

A mature pupa of the Grey Pansy.

After about 6 days of development, the pupal skin of the mature pupa turns translucent and the pupa turns dark brown as a result. Patches of orangy brown can also be noticed in the wing pad. The adult butterfly emerges from the pupa the next day.

A newly eclosed Grey Pansy resting on its pupal case.

References:

• [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 Benedict Tay, Bobby Mun, Loke PF, Sunny Chir, Khew SK and Horace Tan