Random Gallery - The Brown Awl

Random Butterfly Gallery
The Brown Awl (Badamia exclamationis)

This week's random butterfly was a newly-eclosed individual of the Brown Awl (Badamia exclamationis) shot by veteran ButterflyCircle member, Sunny Chir.  His excellent shot of the Brown Awl on a colourful flower won him various accolades in nature and photography online websites including Image of the Week at NatureScapes.Net and Photo of the Month at Nature Photographic Society Singapore. 

Butterfly of the Month - April 2024

Butterfly of the Month - April 2024

The Brown Awl (Badamia exclamationis)

It has been a very hot hot April, with temperatures in Singapore soaring in the high 30's. All over Asia, temperatures are at an unprecedented high, and we are not even in the summer months yet! If this is not climate change, then I don't know what is. Historical highs are being recorded year after year and it is quite widely acknowledged by butterfly watchers and enthusiasts that butterfly populations are down in many parts of Asia, compared to a decade ago.

This month, our feature butterfly is the unremarkable Brown Awl (Badamia exclamationis). This is a skipper from the sub-family Coeliadinae and the only representative of its genus in the region. It is a relatively large butterfly and is a fast-flyer like most Hesperiidae species. I've always been intrigued by the latin species name of this Skipper. It's as though the scientist who first described it screamed out loud when he first discovered this butterfly!

The Brown Awl is moderately rare in Singapore, usually observed singly in the early hours of the morning. It has also been observed to puddle occasionally, but where it is encountered, it is more often seen feeding on moisture off damp rocks, stone walls and timber structures in the cooler morning air. There have been few records of the Brown Awl feeding on flowers.

The species is more often encountered in the forested nature reserves than in urban parks and gardens, although it is widely distributed across Singapore and found in various habitats where its caterpillar host plants, Combretum sundaicum and Terminalia calamansanai (both from the Combretaceae family) are found. Where they are observed, they are usually encountered singly.

A Brown Awl perched on a damp rock after feeding off moisture from the rock

A Brown Awl feeding on the flower of the String Bush at Tampines Eco Green

The wings of the Brown Awl are very elongated and the hindwing is caudate at vein 1b, and strongly excavate between veins 1b and 2. Above, the wings are dark brown with greyish green scaling at the wing bases. The female has prominent and elongated hyaline streaks in spaces 1b, 2 and 3, and the cell in the forewing. In contrast, these streaks in the male are rather small and subdued.

A partial upperside view of a male Brown Awl

On the undersides, both sexes are pale greyish brown and largely unmarked. There is a small yellowish sub-tornal spot in space 1b of the hindwing, which usually goes unnoticed as the hindwings typically fold up at the dorsal area. The prominent veins on the underside gives the butterfly a streaked-like appearance. The abdomen of the butterfly is prominently yellow-banded.

Under leaf behaviour of the Brown Awl where it clings on to the underside of a leaf to rest

The Brown Awl occurs from Sri Lanka, India, China through the Malay Peninsula and Singapore to New Guinea, Australia and as far east as Samoa. In Singapore, it is usually encountered feeding at damp rocks or at flowering plants (uncommonly). It has a habit of perching on the undersides of foliage with its wings folded upright and often adopts this position when it is disturbed and flies off to hide under a leaf.

Text by Khew SK : Photos by Khew SK, Koh CH, Dr Lee PC, Billy Oh, Jonathan Soong and Horace Tan

Awls of Singapore : Part 1

Awls of Singapore : Part 1
Featuring the Awl skippers in Singapore

A Orange Tailed Awl puddles on a damp timber plank

This weekend's blogpost takes a look at the various butterfly species that carry the English common name "Awl". The name Awl usually refers to a group of Hesperiidae (Skippers) that are medium-sized, robust-bodied butterflies classified under the sub-family Coeliadinae. In Singapore, the Awls come from three main genera - Badamia, Bibasis and Hasora.

A Common Awl perches in its typical under leaf pose

I did a word search to investigate the background of the name "Awl" and to look for the possible theories as to why this name was chosen for these butterflies. Invariably, the majority of online dictionaries define awl as a "A small pointed tool used for piercing holes, especially in leather." It is therefore interesting to consider why a butterfly is associated with a pointed tool for its common name!


This is what an "awl" is - a sharp tool to pierce holes in leather

Firstly, is it perhaps the broad bodies of the butterflies and sharply pointed wingtips that gave the early authors the idea that these species are reminiscent of the pointed tool? Or did these authors originally intending to name these butterflies after the bird "Owl" instead? There could always be a possibility that this name was misspelt as Awl? The group of butterflies are known to be crepuscular (active in the dim light in the dawn or dusk hours of the day), and hence could have been associated with nocturnal owls instead?


A Brown Awl extends its long proboscis to feed

It is not common to come across butterflies named after inanimate objects as its common name. In many of my discussions on the English or vernacular common names of butterflies, they are named after birds, animals, colour, people, behaviour, ranks, etc., but names after objects are few and far in between. We will never know for sure, the reasons why the early authors referred to these species as "Awls", but it can always be an interesting subject for debate!



This two-part blog article takes a look at the seven extant species of Awls in Singapore, with Part 1 showcasing three of the seven species. Amongst the butterflies called Awls, five are under the genus Hasora, and one each from the genus Badamia and Bibasis.

1) Brown Awl (Badamia exclamationis)


A Brown Awl feeding on the flower of the String Bush

The first of the Awls is a single genus-single species representative butterfly in Singapore. Globally, there are only two known species in the genus - the other being Badamia atrox, that flies in the islands of New Caledonia and Fiji. The Brown Awl has a large geographical range, starting from India at its western-most range, stretching all the way to Japan in the north-east and Australia in the south-east extremity of its range. In Singapore, the Brown Awl appears intermittently throughout the year, and can be found in the nature reserves as well as urban parks and gardens.


The Brown Awl is regularly observed hiding upside down on the undersides of leaves

The Brown Awl is a medium brown on the upperside, with elongate white hyaline streaks on the forewing in the female. These streaks are near-obscure in males of the species. The wing bases are greyish-green on the upperside. The underside is a drab greyish-brown and unmarked. The abdomen of the butterfly is striped brown and yellow. The wing shape of the Brown Awl is uniquely elongated with the hindwing strongly caudate, giving it a silhouette of a stealth bomber.



The Brown Awl is moderately rare and is usually encountered singly. It has a habit of hiding under leaves with its wings folded upright. It is skittish and a fast flyer. The species has been successfully bred on two caterpillar host plants in Singapore - Combretum sundaicum and Terminalia calamansanai.

2) The Orange Tailed Awl (Bibasis sena uniformis)


An Orange Tailed Awl puddling at a sandy streambank

The Orange Tailed Awl is rare, and a new discovery for Singapore when it was first observed in the forested nature reserves of Singapore. Subsequently, the caterpillars of the species were found in numbers in the Singapore Botanic Gardens on Hiptage benghalensis. However, the adult butterflies are still rarely seen, perhaps due to its crepuscular habits.




The Orange Tailed Awl is dark brown on its uppersides and unmarked. The wings are long and angular with the hindwing tornal cilia a deep orange yellow in pristine individuals. The underside has a broad white discal band on both wings and a purple-blue sheen. The hairs on the legs of the butterfly are orange yellow.

3) The Common Awl (Hasora badra badra)


A Common Awl perches on the underside of a palm frond

The Common Awl is a relatively widespread species in Singapore, and has been observed in urban parks and gardens as well as the forested nature reserves. It is one of five species in the genus Hasora. It is also closely associated with the mangrove and back-mangrove environments where its caterpillar host plant, Derris elliptica, grows wild as a creeper. It tends to prefer shaded habitats and has a habit of flying rapidly and then settling with its wings folded upright on the underside of a leaf to hide itself.



The Common Awl is often encountered puddling at footpaths, bird droppings, damp tree trunks and in the case of the last photo, even on damp brick walls!

The male Common Awl is dark brown above with the wings usually unmarked, although in some individuals, small sub-apical spots may be present. The female has three large pale yellowish sub-apical spots and large hyaline spots in the cell area of the forewing. The underside is brown with a light purplish glaze with a prominent circular white spot in the cell of the hindwing. When photographed with a flash, the purple glaze is enhanced, bringing out a strong purple blue sheen that is not usually seen in natural light.

In the next part of the Awls of Singapore, we take a look at the remaining four Awls that are extant in Singapore, all of which belong to the genus Hasora.

Text by Khew SK : Photos by David Chan, Khew SK, Koh CH, Michael Soh, Jonathan Soong and Horace Tan

Life History of the Brown Awl

Life History of the Brown Awl (Badamia exclamationis)
(This is the 100th article in this life history series at BC Blog)



Butterfly Biodata:
Genus: Badamia Moore, 1881
Species: exclamationis Fabricius, 1775
Wingspan of Adult Butterfly: 45-55mm
Caterpillar Local Host Plants: Combretum sundaicum (Combretaceae), Terminalia calamansanai (Combretaceae).


A Brown Awl perching on a flower bud in a forest clearing.


A Brown Awl taking in the afternoon sun on a fallen branch.

Physical Description of Adult Butterfly:

Adults have elongated wings and the hindwing is caudate at vein 1b and excavate along the termen between ends of veins 1b and 2. Above, the wings are dark brown with greyish green scalings at the wing bases. The female has prominent and elongated hyaline streaks in spaces 1b, 2 and 3, and the cell in the forewing. In contrast, these streaks in the male are rather small and subdued. Below, both sexes are pale greyish brown and largely unmarked. There is a small yellowish sub-tornal spot in space 1b of the hindwing, which usually goes unnoticed as the hindwings typically fold up in the dorsal area.

A partial view of the upperside of a female Brown Awl, note the prominent streaks/spots.


A view of the partially open wings of a male Brown Awl, note the inconspicuous streaks/spots.

Field Observations of Butterfly Behaviour:

This species is moderately rare in Singapore. Adults have been sighted in multiple locations across Singapore, including the Sungei Buloh Wetland Reserve, Mandai Orchid Gardens, Central Catchment Nature Reserve and also rarely in urban parks and residential areas. The fast flying adults have a habit of resting on the underside of a leaf or other plant parts when they rest among the foliage of a tree.

A Brown Awl perching on the underside of a leaf.


A Brown Awl enjoys the sun while perching on a brick in MOG.

Early Stages:

Across its vast area of distribution stretching from South Asia to East Asia, and to South-East Asia and southward to Australia, Brown Awl utilizes host plants in several families. Both recorded local host plants, Terminalia calamansanai and Combretum sundaicum, are in the Combretaceae family. It is thus very likely that more host plants, either in the same family or others, are yet to be discovered locally for the Brown Awl. Caterpillars of the Brown Awl feed on the very young to the moderately young (before hardening) leaves of the host plants.

Local host plant: Combretum sundaicum.

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: 0.6-0.7mm). Prominent ridges run from the pole to the base. The micropylar sits atop at the pole. Initially greyish white in coloration, the entire egg turns wine red as it develops, and then decolorizes again to yellowish red when the caterpillar is ready to emerge.

A close-up view of a young shoot of Combretum Sundaicum, showing two eggs of the Brown Awl.


Two views of a 1-day old egg of the Brown Awl.


Two views of a mature egg of the Brown Awl, note the black larval head visible through the egg shell.

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 1.5mm. It does not make an attempt to devour the egg shell after its emergence. The golden and cylindrical body has a number of very short white setae. The large head is black, slightly bi-lobed and lightly hairy. The body turns pale yellowish green as it feeds on the leaf lamina and grows in this initial instar.

Two views of a 1st instar caterpillar, early in this stage, length: 1.7mm.


Two views of a 1st instar caterpillar, length: 1.9mm.

The young caterpillar constructs its first shelter by spinning a silk web over a void of space on the young shoot. It rests within the shelter and ventures out to eat on nearby leaf surface. In later instars, the Brown Awl caterpillars also construct leaf shelters but do so by joining leaf blades together. The larval growth of the Brown Awl is rapid in pace for all instars, with all but the final instar lasting only 1.5-2.5 days.

A late first instar caterpillar in its shelter. The focus was varied to show details in the net of silk threads securing the shelter.

After reaching a length of about 3.4-3.8mm in the 1st instar, the caterpillar moults to the next instar after a short dormant period. The 2nd instar caterpillar is pale yellowish green with a faint brown rings on its body segments, from the pro-thorax to the 8th abdominal segment. The yellowish head has an upper transverse brown stripe and two lower short stripes on each side of the adfrontal area. The body and the black head capsule are covered in numerous tiny setae.

Two views of a 2nd instar caterpillar, length: 5mm.


A second instar caterpillar in its shelter.

The 2nd instar caterpillar reaches a length of about 6.5-7.5mm, and after 1.5-2 days in this stage, it moults again. The 3rd instar caterpillar has 14 dark brown to black black rings, bold and prominent against the pale yellowish green of the body ground color. There is one ring to each of the 13 body segments and one on the posterior body edge. On the yellow head, the stripes have also become darker and more prominent. This instar lasts another 1.5-2 days with the length reaching 12mm.

Two views of a 3rd instar caterpillar, length: 9.5mm.

The 4th instar caterpillar resembles the 3rd instar caterpillar mostly but has additional intra-segmental dark rings, typically 3 to each segment. These rings are much thinner in width compared to the inter-segmental rings. This penultimate instar takes about 1.5-2 days to complete with the body length reaching up to 21mm.

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

The final and 5th instar caterpillar has similar body markings as the 4th instar caterpillar. Noteworthy is that dark inter-segmental rings are particularly broader in the 2nd, 4th, 6th and 8th abdominal segments. On the head capsule, the transverse black stripes seen in the earlier instars are now broken into short and bold dash-like stripes. This stage takes about 3-4 days to complete with body length reaching up to 46mm.

Two views of a 5th instar caterpillar, early in this stage, length: 30mm.


Two views of a 5th instar caterpillar, later in this stage, length: 43mm.

Towards the end of 5th instar, the body of the caterpillar gradually shrinks in length. The fully grown caterpillar ceases feeding and stations itself in a leaf shelter. During the early part of this pre-pupal stage, the caterpillar constructs a silk girdle across the dorsum of its anterior abdominal segments, and a short transverse silk band on the substrate 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 pre-pupa of the Brown Awl.

After about 1 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 golden brown rostrum. Fresh after the pupation event, the body is pale golden brown to dark brown, but after 0.5 to 1 day, the body surface becomes mostly covered in a white substance. Length of pupae: 24-26mm.

A Brown Awl caterpillar turning into a pupa.

Two views of a pupa of the Brown Awl at any early stage with white substance just appearing on the surface.


Two views of a pupa of the Brown Awl, after the white substance has fully formed on the surface.

After 7-8 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 Brown Awl


A newly eclosed male Brown Awl.

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
• A Photographic Monograph on Hong Kong Butterflies, Vol. 4, Hong Kong Lepidopterists Society, 2011.

Text by Horace Tan, Photos by Sunny Chir, Khew SK, and Horace Tan