Life History of the Great Orange Awlet

Life History of the Great Orange Awlet (Burara etelka)



Butterfly Biodata:
Genus: Burara de Nicéville, 1895
Species: etelka Hewitson, 1866
Wingspan of Adult Butterfly: 60mm
Caterpillar Host Plants: Combretum sundaicum (Combretaceae)

Physical Description of Adult Butterfly:
Burara etelka (The Great Orange Awlet) is a rather large species with the wingspan up to 1cm longer than the look-alike and more common species, Burara harisa (The Orange Awlet). Above, the male is dark brown with no brand; the female is dark brown with basal halves of all wings shining greenish blue. Underneath, both sexes are shaded orange with the hindwings particularly so. Basal halves of the forewings are shaded purplish blue, more extensive and shining in the female. Both sexes have orange tornal cilia on the hindwings. The head, legs and the ventral surface of the the thorax are colored orange. Numerous orange hairs are also featured on the thorax and abdominal segments.


Two Burara etelka resting on stems in the nature reserve.


Another Burara etelka found in the nature reserve.

Field Observations of Butterfly Behaviour:
The adult of this species is rarely encountered in Singapore, due likely to their habit of being more active at dawn and dusk. In contrast, the caterpillars are more readily found in leaf shelters on its host plant, Combretum sundaicum, which is a common creeping weed in the Central Catchment Nature Reserve. As typical with other skippers, the adults fly with swift, strong and darting flights.

Early Stages:


Host plant: Combretum sundaicum.

The eggs are laid singly on the leaf upperside of a middle-aged or mature leaf of the host plant. Each egg is creamy white with a beige tinge. It is dome-shaped with a flat base. The micropylar sits atop and a number of vertical ridges running longitudinally from it. The diameter is about 1.2mm.


Two views of an egg of Burara etelka


Mature egg with a faint view of the head (left), empty egg shell (right)

It takes 3 days for the collected egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 3mm. Its pale brown body is cylindrical in shape with rather long lateral and sub-spiracular white setae. The large head is pale brown with black markings and bears similar white setae as those on the body. All instars of Burara etelka caterpillars feed on either the middle-aged or mature leaves of Combretum sundaicum, and ignore the young and tender leaves on new shoots.


Newly hatched 1st instar caterpillar, length: 3mm

The body soon takes on a green undertone after a few feeding sessions on the leaf. Its movement on leaf was observed to be rather quick-paced. As the growth continues in this first instar, faint lateral markings start to appear. By the time the caterpillar lies dormant for its moult to the 2nd instar, its length has reached 6mm and black rings are discernible on the body, one to each segment. The 1st instar takes a total of 2 days to complete.


1st instar caterpillar, length: 4mm


1st instar caterpillar, late in this stage, length:6mm.

The body of the 2nd instar caterpillar has a ringed appearance with a black ring of irregular thickness and 4-5 white and yellow rings on each segment. The head is pale orange with two horizontal black stripes. Both the head and the body also feature short white setae. This instar lasts a total of 3 days with the body length reaching about 11-12mm.


2nd instar caterpillar, early in this stage, length: 7mm


2nd instar caterpillar, late in this stage. Lengths: 10mm (top); 12mm (bottom).

The 3nd instar caterpillar resembles the 2nd instar caterpillar closely in markings and coloration. This instar lasts a total of 3-5 days with the body length reaching about 18-19mm.


3rd instar caterpillar, early in this stage. Length: 11.5mm.


3nd instar caterpillar, late in this stage. Length: 14mm.

The 4th instar caterpillar is bright yellow in body color. A prominent and broad dorsal black stripe, running from the prothorax to the 7th abdominal segment, is featured with two finer white band embedded within. Each body segment has a large and irregularly-shaped black spot laterally, of which several are connected to the dorsal stripe. The head is orange with a broad black central and vertical stripe (split at upper end) crossed by two black horizontal stripes, giving it a close resemblance to some Chinese Opera masks. Both the body and the head also sport numerous short setae. This instar lasts 3-5 days with the body length reaching up to 28-29mm.


4th instar caterpillar, early in this stage, length: 20mm


4th instar caterpillar, late in this stage, length: 25mm

The 5th instar caterpillar has similar body color and markings to the 4th instar caterpillar with the only discernible difference being a greater proportion of black in the dorsal band, lateral body spots and head stripes. This instar takes about 4-6 days to complete with the body length reaching 37-38mm.


Two views of a 5th instar caterpillar, early in this stage. Length: 26mm.

As is typical of most hesperiid species, the caterpillars of Burara etelka also build leaf shelters on the host plant. Typically a fragment of the leaf lamina is cut and folded inwards and secured with silk threads to create a sufficiently large void of space in which the caterpillar rests and hides between feeds.


The leaf shelter of a late instar caterpillar of Burara etelka sighted in the western nature
reserve with a bird paying close attention to it nearby.

A short sequence of a 5th instar caterpillar chomping on leaf lamina.

The 6th and final instar caterpillar continues the increase of the proportion of the dark color in various markings to the extent that the dark color switches its role to become the base color. Now yellow color is confined to oval lateral spots, a pair to each body segment. The dark base color reveals itself as dark reddish brown upon closer look. Again, numerous short and white setae covers the body and the head. This stage takes about 9-12 days to complete with the body length reaching 65-66mm.


6th instar caterpillar, early in this stage, length: 39mm


6th instar caterpillar, late in this stage, length: 55mm


The interesting change in appearance of markings on the posterior abdominal segments
from the 3rd to the 6th instar (left to right).

At the end of 6th instar, the body of the caterpillar shortens rather drastically to about 35mm in length. Soon it becomes dormant in its leaf shelter and enters the prepupatory phase which lasts for one day.


Two views of a pre-pupa of Burara etelka.

Pupation takes place within the leaf shelter. The pupa secures itself with its cremaster attached to a short transverse band on the leaf surface, and has a silk girdle. It has a short thorax, a rather long abdomen, a short and pointed rostrum. The body is initially pale pink to purplish with large yellow lateral spots and black markings. However within a day all yellow spots fade away with the base color becoming milky white. Length of pupae: 30-32mm.


Two views of a fresh pupa of Burara etelka


Two views of a pupa of Burara etelka, length: 30mm

After 9 days, the pupa becomes mostly black in color in the wing pads and in the body segments. Eclosion takes place the next day.


Two views of a mature pupa of Burara etelka, shortly before the eclosion event.

A newly eclosed Burara etelka drying its wings.

Another newly eclosed Burara etelka

Note: The above life history record is based on observations of three larvae collected and bred over their last three instars, yet another over its last five instars, and one bred from a collected egg, on five separate occasions over a period of 1.5 years. Six instars were evident in the last two larvae bred. However this does not preclude the possibility of utilization of five instars, typically of most hesperiid speces, in other Burara etelka larvae.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.


• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

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

Life History of the Orange Awlet

Life History of the Orange Awlet (Burara harisa consobrina)




Butterfly Biodata:
Genus: Burara Swinhoe, 1893
Species: harisa Moore, 1866
Sub-species: consorbrina Plötz, 1884
Wingspan of Adult Butterfly: 45-50mm
Caterpillar Local Host Plant: Arthrophyllum diversifolium (Araliaceae)

Physical Description of Adult Butterfly:

Burara harisa  (The Orange Awlet) is the look-alike cousin of the larger (and less common)  Burara etelka  (The Great Orange Awlet). Above, the male is coppery brown with no brand; the female is deep steely blue with greenish wing base. Underneath, both sexes are shaded in dark orangy brown and have pale orange streaks beyond the cell-end on both wings. Basal halves of the forewings are shaded purplish blue, more extensive and prominent in the female.  Orange  cilia are found on the hindwings, along the termen from spaces 1 to 3. The head, palpi, legs and the ventral surface of the thorax and abdomen are colored orange.

Field Observations of Butterfly Behaviour:

The adults can be found in the nature reserves as well as the Southern Ridges. They are more likely to be encountered in early morning hours and late afternoon, frequenting shaded forest areas. At times adults can be found nectaring at  flowering plants and puddling at damp grounds. Compared to the adults,  the larval stages are more readily found in leaf shelters on its host plant, Arthrophyllum diversifolium, which is a relatively common plant growing in the reserves as well as urban parks. The adults fly with swift, strong and darting flights. 

Early Stages:

The caterpillars of the Orange Awlet feed on the leaves of the host plant, Arthrophyllum diversifolium, and seek concealment and protection in  a leaf shelter. For its shelter, an early instar caterpillar typically makes a sinuous cut from the leaf edge, and proceeds to fold the leaf fragment onto the leaf underside where silk threads are used to secure the leaf edge to the leaf surface. The shelters for the much larger caterpillars in late instars are simply made by joining the two opposing edges of a leaf.

 

The leaf shelter of an early instar caterpillar seen on the leaf underside of the host plant.

 

A leaf shelter of a late instar caterpillar of the Orange Awlet.

 

A young specimen of the local host plant: Arthrophyllum diversifolium.

A far view of an Arthrophyllum diversifolium in a Hill Park  bearing signs of an infestation of the Orange Awlet.

The eggs are laid singly on the leaf upperside of a middle-aged or mature leaf of the host plant. Each dome-shaped egg is creamy white with a beige tinge. The micropylar sits atop and a number of vertical ridges running longitudinally from it to the base. An equatorial series of short, reddish, intermittent patches can be seen as the egg develops. The diameter is about 1mm.

Two views of an egg of the Orange Awlet
 
 
A sequence of three views of a maturing egg of the Orange Awlet over a span of 2 days.

It takes 3-4 days for the collected egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 2.9mm. Its pale  yellowish brown body is cylindrical in shape with rather long lateral and sub-spiracular white setae. There are dorso-lateral dark brown markings on a number of body segments.   The large head is pale brown with three black roundish markings. The head also bears similar white setae as those on the body. 

Newly hatched 1st instar caterpillar, length: 3mm

The body soon takes on a green undertone after a few feeding sessions on the leaf. Its movement on leaf was observed to be rather quick-paced.  By the time the caterpillar lies dormant for its moult to the 2nd instar, its length has reached 4.5mm. The 1st instar takes a total of 2.5-3.0 days to complete.

1st instar caterpillar, late in this stage,  length: 4.5mm

Top: late 1st instar caterpillar prior to its moult. Bottom: newly moulted 2nd instar caterpillar.

The body of the 2nd instar caterpillar is yellowish green and has prominent black dorso-lateral patches on the thoracic segments, 2nd, 4th, 6th, 8th and 9th abdominal segments. The black marking on the 10th segment form a black stripe across the dorsum. There is a pair of faint yellowish dorsal bands and faint obligue markings between the black spots.   The head is pale orange with two rows of black spots.  This instar lasts about 3-4 days with the body length reaching about 9mm.

2nd instar caterpillar, early in this stage, length: 6.5mm

2nd instar caterpillar, dormant prior to its moult, length: 8mm.

The 3nd instar caterpillar resembles the 2nd instar caterpillar closely in markings and coloration. The dorsal bands and dorso-lateral bands/stripes are more prominent now, yellowish in abdominal segments and becoming whitish in the thorac segments.  This instar lasts a total of 3-4 days with the body length reaching about 14mm.

3rd instar caterpillar, length: 11.5mm.

3rd instar caterpillar, dormant prior to its moult,  length: 13.8mm.

The 4th instar caterpillar resembles the 3rd instar caterpillar closely but has additional black spots/markings appearing between the yellowish/whitish dorsal and dorso-lateral bands.   Both the body and the head sport numerous short setae. This instar lasts 3-4 days with the body length reaching up to 25mm.

4th instar caterpillar,  length: 24mm.

4th instar caterpillar, dormant prior to its moult, length: 23mm

The 5th instar caterpillar has larger and very prominent black spots and markings on all body segments. With more black patches filling in the spaces between the whitish/yellowish dorsal and dorso-lateral bands, it gives the impression of large saddle patches, one to each segment,  being traversed and criss-crossed by the whitish/yellowish lines.  This instar takes about 6-7 days to complete with the body length reaching 40mm.

A newly moulted 5th instar caterpillar, length: 23mm.

Two views of a 5th instar caterpillar, length: 35mm.

Two views of a 5th instar caterpillar, late in this stage, length: 40mm

Towards the end of  5th instar, the body of the caterpillar shortens gradually and its body base colour decolorised to a shade of beige with pink tinge between the black spots.  It then stays in its leaf shelter to become a pre-pupatory larva. Within the shelter, the pre-pupa prepares for the pupal phase with a series of silk construction work with the main pieces being a silk girdle across the dorsum of its anterior abdominal segments, and a short and thickened transverse silk band on the substrate near its posterior end. Both the dorsal point of the girdle and the transverse band are further secured by vertical/oblique threads to the inner wall of the shelter. Soon the pre-pupa becomes dormant in its leaf shelter and enters the prepupatory phase which lasts for about 0.5 to 1 day.

A final instar caterpillar of the Orange Awlet eating away on a nearly defoliated branch in the nature reserve.

Two views of a pre-pupa of the Orange Awlet.

Pupation takes place within the leaf shelter. The pupa is secured  with its cremaster attached to the short transverse band on the substrate and has a silk girdle. It has a short thorax, a rather long abdomen, a short and pointed rostrum. The body is initially orangy with reddish patches and large black spots. However all these markings fade away after a day and  the base color becomes a uniform pale milky yellow. The body becomes coated in a thin layer of whitish powerdery substance. There is a series of small dorso-lateral black spots on all body segments. Another series lines  the leading edge of mesothorax and one solitary spot sits atop the dorsum of mesothorax. Length of pupae: 22-23mm.

An Orange Awlet catarpillar moults to a pupa.

Two views of a  pupa of the Orange Awlet

After 8-9 days, the pupa becomes mostly black in color in the wing pads and parts of  the body segments, signally the end of development of the adult lying within. Eclosion takes place the next day.

Two views of a mature pupa of the Orange Awlet.

A newly eclosed Orange Awlet.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006
• A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2010.

Text by Horace Tan, Photos by Loke PF,  Sunny Chir  and Horace Tan