Life History of the Yellow Banded Awl

Life History of the Yellow Banded Awl (Hasora schoenherr chuza)



Butterfly Biodata:
Genus: Hasora Moore, 1881
Species: schoenherr Latreille, 1824
Subspecies: chuza Hewitson, 1867
Wingspan of Adult Butterfly: 45mm
Caterpillar Local Host Plants: Two species to be identified.


A Yellow Banded Awl perching the broken end of a branch.


A Yellow Banded Awl perching on the underside of a palm frond.

Physical Description of Adult Butterfly:

Adults are rather large in size with pointed forewing apex and markedly lobate hindwings. Above, the wings are dark brown. For both sexes on the forewing, there are four whitish sub-apical spots, and three rather large yellowish hyaline spots, one each in the cell and in spaces 2 and 3. These hyaline spots are adjoined to form a broad but irregularly-outlined band. The male has a yellowish discal stigma. On the hindwing, there is a broad yellowish discal band and the wing borders are marked with yellowish cilia. Below, both sexes are similarly marked as per the upperside but with wing bases in paler brown, and that the apical to post-discal area of the forewing has a strong purplish sheen in some specimens.

A partial view of the upperside of a Yellow Banded Awl.


A side view of the same Yellow Banded Awl featured in the previous picture.

A Yellow Banded Awl found perching on the underside of a leaf after a shower.

Field Observations of Butterfly Behaviour:

This species is uncommon in Singapore. Sightings of the adults have so far been confined to a handful of locations within the Central Catchment Nature Reserve. Typical encounters involve an individual flying among foliage alongside walking trails or at forest fringes, and occasionally puddling individuals on damp patches of soil. As with other Awl spp., the fast flying adults have a habit of resting on the underside of a leaf or other plant parts.

A Yellow Banded Awl puddling on a damp ground.


A Yellow Banded Awl checking out the surface of a leaf with its proboscis.

A Yellow Banded Awl perching on a tree trunk in the nature reserve.

Early Stages:

Two vines growing in the Catchment Reserve have been recorded as the local host plants. The first is tri-foliated with smooth leaf surface while the second is 5-foliated with leaf surface covered with dense short hair. Their exact species ID are yet to be established. Igarashi and Fukuda, in their voluminous book on life histories of Asian butterflies, mentioned Fordia ngii (Malay Peninsula) and Spatholobus palawanensis (Palwans) as host plants of the Yellow Banded Awl. It is likely that the two local host plants also belong to the same genera (within Leguminosae). Caterpillars of the Yellow Banded Awl feed on the very young to the moderately young (before hardening) leaves of the host plants.

Host plant #1; a vine with tri-foliated leaves, with smooth leaf surface.


Host plant #2: a vine with 5-foliated leaves, with "rough" leaf surface.

The eggs are laid singly on very young shoots of the host plants. Each egg is shaped like a bun with a flattened base (diameter: 0.8-0.9mm). Prominent ridges run from the pole to the base. The micropylar sits atop at the pole. The entire egg turns salmon red as it develops, and then decolorizes again when the caterpillar is ready to emerge.

Two views of an egg of the Yellow Banded Awl, likely be one-day old.


Two views of a mature egg of the Yellow Banded Awl.

Two views of an empty egg shell of the Yellow Banded Awl.

It takes 2 days for the collected egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 2mm. It has the typical cylindrical shape for skipper caterpillars, and the yellowish body has a number of short white setae and lateral orangy patches. The large head is black, slightly bi-lobed and lightly hairy. The dorsum of the prothorax carries a dark-colored patch/shield.

Two views of a 1st instar caterpillar, early in this stage, length: 2.3mm.


A newly hatched caterpillar checking out its surrounding on host plant #2.

The young caterpillar constructs its first leaf shelter by bringing two halves of a small young leaf together with silk threads. It rests within the flap and ventures out to eat on nearby leaf surface. In later instars, the Yellow Banded Awl caterpillars also construct leaf shelters in a similar fashion but do so with larger and older leaves. The larval growth of the Yellow Banded Awl is rapid in pace for all instars, with all but the final instar lasting only 1-1.5 days.

A field shot of a pinna of host plant #2 showing an empty eggshell and a 1st instar caterpillar in a leaf shelter.


Two views of a 1st instar caterpillar, late in this stage, dormant before its moult, length: 3.5mm.

After reaching a length of about 3.5mm in the 1st instar, the caterpillar moults to the next instar after a short dormant period. The 2nd instar caterpillar has four faint whitish narrow dorsal bands which are barely visible against the yellowish green ground color. There are lateral patches, brown initially but blacken gradually, one to each of all body segments except for the anterior two. The body and the black head capsule are covered in short fine setae. Toward the end of this instar, faint pale rings become visible on the body segments.

Two views of a 2nd instar caterpillar, early in this stage, length: 5mm.


A 2nd instar caterpillar, late L2. Top: length: 7mm. Bottom: dormant before the next moult.

The 2nd instar caterpillar reaches a length of about 7mm, and after 1.5-2 days in this stage, it moults again. The 3rd instar caterpillar resembles the 2nd instar caterpillar but with broader and more prominent dorsal yellowish bands and segmental yellowish rings, all set against a more greenish body colour. The lateral dark patches are now more prominent on meta-thoracic segment, abdominal segments 2,4,6,8-10 but those on other segments appear to fade away. This instar lasts another 2 days with the length reaching 11-12mm.

Two views of a 3rd instar caterpillar, newly moulted, length: 7.5mm.


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

A 3rd instar caterpillar, dormant before the next moult, length: 13mm.

The 4th instar caterpillar resembles the 3rd instar caterpillar closely, but with dorsal bands and segmental rings much more constrasting, and the dark lateral patches better defined. The head capsule is still black for most 4th instar caterpillars, but some specimens have been observed to feature small lateral patches of red to reddish brown. This penultimate instar takes about 2 days to complete with the body length reaching up to 24mm.

Two views of a 4th instar caterpillar, newly moulted, length: 12mm.


Two views of a 4th instar caterpillar, length: 15.5mm.


Two views of a 4th instar caterpillar, length: 22mm.

A 4th instar caterpillar, dormant before the next moult, length: 24mm.

The final and 5th instar caterpillar has similar body markings as the 4th instar caterpillar. Noteworthy is that an additional pair of dark lateral patches, though small in size, appear on the meso-thorax. A much more striking change is in the head capsule which has now become reddish or orangy red. Set against this brightly coloured background are two lateral round black spots and one triangular black spot on the frons (about the labrum). White setae adorn the head capsule as well as the entire body. This stage takes about 4-5 days to complete with body length reaching up to 42mm.

Two views of a newly moulted 5th instar caterpillar, early in this stage, length: 23mm.


Two views of a 5th instar caterpillar, late in this stage, length: 42mm.

Towards the end of 5th instar, the body of the caterpillar gradually shrinks in length and decolorises, losing all its yellow luster in the process. The fully grown caterpillar ceases feeding and stations itself in a leaf shelter. During the early part of this pre-pupal stage, the caterpillar spins large quantity of silk threads to seal the pupation shelter, and in particular, constructs a silk girdle at its 2nd/3rd abdominal segment and a short transverse silk band near its posterior end. Both the dorsal point of the girdle and the transverse band are also secured by vertical/oblique threads to the inner wall of the shelter.

Two views of a 5th instar caterpillar, ceased feeding and shrunken, length:30mm.

Two views of a pre-pupa of the Yellow Banded Awl secured in its pupal shelter. Note the dorsal girdle and posterior transverse band.

After about 0.75 day of the pre-pupal phase, pupation takes place within the pupation shelter. The pupa secures itself with its cremaster attached to the transverse band. The pupa has a short thorax, a rather long abdomen and a short and pointed black rostrum. Fresh after the pupation event, the body is pale whitish with a light greenish undertone, but after 0.5 to 1 day, the body surface becomes mostly covered in a white substance. Several black spots adorn the dorsum of the thoracic segments. The spiracles are marked in black. Length of pupae: 22-23mm.

Two views of a pupa of the Yellow Banded Awl, early in this stage, still without the coating of whitish powdery substance.


Two views of a pupa of the Yellow Banded Awl, day 2 in this stage, now with the coating of whitish powdery substance.

After 8 days, the pupa becomes darkened in color signaling the imminent emergence of the adult. The next day the adult butterfly emerges from the mature pupa.

Two views of a mature pupa of the Yellow Banded Awl


A newly eclosed male Yellow Banded Awl still awaiting its wings to be fully stiffen up.

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
• The Life Histories of Asian Butterflies Vol.2, Igarashi S. & Fukuda H., Tokyo University Press, 2000.

Text by Horace Tan, Photos by Nelson Ong, Sunny Chir and Horace Tan

Butterfly Photography at Our Local Parks - AMK Town Garden West

Butterfly Photography at Our Local Parks
Featuring : Ang Mo Kio Town Garden West



This urban park, developed on a hillock, is the bigger of two town parks at Ang Mo Kio Town. Flanked on two sides by roads - Ang Mo Kio Ave 5 and Ave 6, and on the other two sides by residential estates, this park boasts a total area of about 21 Hectares.

A 120-step concrete staircase takes you up to a small shelter mid-way and up to a plaza right at the top where you can view the lush greenery and landscaping from a high vantage point.

Rows of majestic Livistonia palms rising a few stories high, line the steep slope, creating a formal colonnade of natural columns, drawing the eye upwards and towards the plaza at the top of the hill. At the entrance to the park from AMK Ave 6, there is a small pergola adorned with the pink flowers of the Honolulu creeper (Antigonon leptopus). To the right of this pergola is a large pond covered with water lilies.

A small patch of Lantana surrounded by tall Dracaena marginata shrubs and other palms, greet visitors to the park. The Lantana flowers attract several species of butterflies, like the Peacock Pansy, Lemon Emigrant and the Leopard.

Along the foot of the slope the landscaping changes to patches of Snakeweed (Stachytarpeta indica) and another larger related species, the Pink Snakeweed (Stachytarpeta mutabilis) interspersed with lower ground cover of various other flowering plants.

The patches of Snakeweeds wind sinously up the slope and the flowers of both species of the "weed" attract many butterflies like the Chocolate Pansy, Lemon Emigrant and Common Grass Yellow.

Moving up the slope the planting changes further with patches of Singapore Rhododendron and the Powderpuff Flower (Calliandra haematocephala) and various other leafy plants. Past the shelter (which comes in handy if it rains) one moves further up and the planting along the slope changes again, but this time of the green leafy varieties.

At the final flight of steps up to the small plaza right at the top of the slope is a diamond-shaped kerbed planter that is filled with more Snakeweed, Peacock Flower and a rather lush growth of Bidens sp. It was interesting to note that the Bidens sp. sport exceptionally tall and leafy green leaves and not too many flowers. At the location, there were many skippers like the Small Branded Swift, Formosan Swift, Grass Demon as well as the fast-flying Pierids like the Striped Albatross and Lemon Emigrant.

A Common Mormon flies past, as I was trying to shoot a sun-bathing Formosan Swift, as several individuals of Common Grass Yellow flutter around the flowers and leaves of the Peacock Flower - some ovipositing on the leaves. A couple of Chocolate Pansies frolick in the warm morning sunshine.. A solitary Common Mime makes a hurried pit-stop at the purple flowers of the Snakeweed, taking a quick sip of nectar, before flying off quickly.

As I sat at the plaza watching the butterfly activity, there were several people practising Qi Gong on the lower level, and many joggers running by, obviously regulars at this park. Several families with their kids screaming gleefully can be seen (and heard) on the lower terrace jogging paths. A lady sat on the granite balustrade of the plaza, totally absorbed in her book, and oblivious to the butterflies that were fluttering beside her.

Danger lurks amongst the bushes. This Changeable Lizard waits stealthily for its prey

Just below the plaza platform, was a patch that was allowed to grow "wild". It appears that this patch was reserved as a community gardening patch with various recognisable herbs and spice plants like Lemon Grass, Pandan, Banana and so on.

As the morning grew hotter, I made my way back down towards the pond. Along the way, I encountered a few Leopard butterflies frolicking restlessly near their host plant of Flacourtia inermis. Back at the Lantana patch, I was surprised to see a Copper Flash and the Yellow Palm Dart (our new migrant from Australia). It was some time since I last saw one of these species that we can now consider one of our "foreign talents" that has made Singapore its home. You can read about the discovery of this species in an earlier blog article.

The Yellow Palm Dart, Cycad Blue, Common Dartlet and a Bamboo Paintbrush Swift

At the road level, the pond is a welcoming sight to visitors, particularly in the early morning when the vibrant pink water lily flowers dot the surface of the pond.

This waterbody is a dragonfly enthusiast's haven, with at least 10 or more species flying around the edges of the pond and resting on their favourite perches, returning time and again, even when disturbed.

Along the fringe of the pond, a number of Saraca cauliflora trees were in full bloom, with their attractive orange-yellow flowers busy with Lemon Emigrants and Painted Jezebels.

Location Map of Ang Mo Kio Town Garden West

Here we have an urban oasis, with lush greenery, attractive flowers, butterflies, dragonflies and birds all thriving in proximity to HDB apartments and the busy traffic thoroughfare in Ang Mo Kio New Town. I have not explored the full 21 Ha of the park, with its many jogging tracks, a bird-singing plaza and several other features. But the landscaped area, busy with butterflies would keep many an enthusiast occupied for an hour or two.

So if you have a couple of hours to spare and would like to shoot some urban butterflies, this park is conveniently located, and on Sundays, the limited number of carparks alongside Ang Mo Kio Ave 6 is free of charge! And if you're hungry or thirsty after the short walk and a morning of butterfly watching, the MacDonald's outlet is just about 100m away from the main plaza.

Text & Photos by Khew SK

Acknowledgements :


Ms Chong Siew Chuen, Parks Officer, Community Parks, National Parks Board, who was a key person who helped to create the butterfly-attracting landscaping at AMK Town Garden West.

Further Reading :


NParks Website - AMK Town Garden West

Re-Discovery of the Detached Dart

Re-Discovery of the Detached Dart (Potanthus trachala tytleri)

Species #296 of the Singapore Butterflies Checklist

Happy New Year to all ButterflyCircle members and blog readers. It is the 1st of January of the year 2011, and we start off the year with some good news with the addition of one more species to the Singapore Checklist. The checklist is now at 296 species and counting, and we hope that the year 2011 will bring more good cheer.

A clump of the host plant of at least 4 different species of skippers - all on the same plant!

A shot of the inflorescence of the host plant and a close up of the florets

On a late Sunday afternoon, whilst out on a short butterfly photography outing at a urban park when I came across a number of leaf shelters on a clump of long grass (possibly Panicum maximum - to be confirmed). Knowing that there would likely be caterpillars of the Hesperiidae, I checked the leaf shelters and discovered at least 5-6 caterpillars of various instars on the grass blades.

A female Formosan Swift (Borbo cinnara) ovipositing on the host plant that three other species of caterpillars were found, including that of the Detached Dart

Interestingly, the caterpillars appeared different and were likely to be of different species. As this was an opportune moment to record the life histories of some of these skipper species, I passed the caterpillars to Horace Tan, our avid cat farmer, in whose good hands I would be certain would see the caterpillars bred successfully and documented in Horace's usual meticulous recording.

Amongst the species that were successfully bred were the Palm Dart (Telicota augias augias), Full Stop Swift (Caltoris cormasa) and a Potanthus sp. which we could not identify with certainty. Horace later obtained a few more eggs to complete the life history of this Potanthus from the same clump of host plant.

However, the early stages of the caterpillar seemed to coincide with the pictures documented in the Butterflies of Hong Kong (Bascombe, Johnston & Bascombe) for the species Lesser Band Dart (Potanthus trachala). The distinctive head capsule and anal plate of the 5th instar caterpillar matches the same species on Plate 105 of the book, showing in full colour the early stages of this species.

Upon eclosion, the male and female specimens were examined and matched against the various references and ID keys. After consulting two experts - one from Hong Kong and one from Malaysia, it was confirmed that the species thus bred from the eggs and caterpillar found at this urban park was indeed Potanthus trachala tytleri.

It is curious though, that the same species is given different common English names in different regions. In the Hong Kong references, this species is called the Lesser Band Dart. In Indian website references, this species is called Detached Dart. In our main Thai reference, Butterflies of Thailand, also calls it the Detached Dart. However, another Thai website calls it the Broad Bident Dart.

For consistency of the common names given to the species in the South East Asian region covering Thailand, Malaysian and Singapore, we will give preference to the name Detached Dart, taking reference from the name given in the Butterflies of Thailand book by Pisuth Ek-Amnuay.

The Detached Dart is larger than the typical Potanthus species and usually larger than the more commonly encountered Lesser Dart (Potanthus omaha omaha). It has a wingspan of about 28-30mm, compared the the Lesser Dart's 20-24mm. and the Large Dart's (Potanthus serina) 30-35mm.

The species can usually be separated from the other species in the genus in that the spots in spaces 4 and 5 of the forewing above are detached and out of line from the spots below. The post-discal spots in spaces 2 and 3 are outwardly concave and deeply excavated. On the upperside of the hindwing, there is usually a conspicuous spot in space 7 and none in space 6. The underside is dark brown with yellow dusting.

In the field, it is not easy to spot the differences amongst the lookalike Potanthus species, and it was only with this chance discovery of the early stages of this species that we now re-instate the Detached Dart to the Singapore Checklist. Given this find, there is always the possibility that more of the Potanthus species occur in Singapore as well. It will only be matter of time and luck that will yield more of these lookalike species to be added to the checklist in due course. Special thanks to Horace Tan for re-discovering this species through his recording of the early stages of the Detached Dart.

Text by Khew SK ; Photos by Horace Tan & Khew SK

References :

• [C&P4] 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
• The Butterflies of Hong Kong, M. Bascombe, G. Johnston, F. Bascombe, Princeton University Press 1999
  

Acknowledgments :

• National Biodiversity Centre, National Parks Board, Singapore for issuing official research permits to selected members of ButterflyCircle to collect and document early stages of butterflies on State Land under NParks' jurisdiction