16 November 2024

Life History of the Grey Tinsel

Life History of the Grey Tinsel (Catapaecilma major emas)


Butterfly Biodata:
Butterfly Biodata :
Genus : Catapaecilma Butler, 1879
Species : major H.H. Druce, 1895
Subspecies : emas Fruhstorfer, 1912
Wingspan of Adult Butterfly : 16-20mm
Caterpillar Host Plants : Sonneratia ovata (Lythraceae, common name: Mangrove Apple), Avicennia rumphiana (Acanthaceae, common name: Api-api bulu).



A male Grey Tinsel.

Physical Description of Adult Butterfly:
On the upperside, the male is purplish blue with narrow black borders whilst the female is blue with broad dark borders. On the underside, the wings in both sexes are pale buff brown but gradually turning greyish towards the termen. The wings are adorned with prominent silver markings and irregular black spots. In the forewing, post-discal spots in spaces 4 and 5 are in line. The hindwing has three pairs of white-tipped filamentous tails at the end of veins 1b, 2 and 3 respectively, with the one at vein 2 being the longest. Legs are very hairy. Eyes and palpi are hairy as well.

A frontal view of a Grey Tinsel depicting its hairy legs clearly.

A close-up view of a Grey Tinsel showing the silvery markings and black spots.

A Grey Tinsel resting on the underside of a leaf of Api-api bulu.

Field Observations:
The Grey Tinsel is rare in Singapore. It is typically found in the vicinity of mangrove swamps in the north-eastern part of the main island of Singapore and in Pulau Ubin. The adults are small butterflies with a rapid flight. They have been observed to sunbathe at certain hours of the day. Females have been seen to visit its choice host plant to oviposit over a period of a week or two.

A female Grey Tinsel resting on the underside of a leaf of Sonneratia ovata.

A female Grey Tinsel.


Early Stages:


A video clip showing various stages of the life cycle of the Grey Tinsel.

Thus far two local host plants have been identified for the Grey Tinsel. Both are mangrove plants, namely, Sonneratia ovata and Avicennia rumphiana. On these plants, the early stages of the Grey Tinsel feed by grazing on the surface of mature leaves and scraping the skin of stems. The mother Grey Tinsel typically ovisposits on a selected host plant where there is a presence of large ant colonies of a Crematogester species. The caterpillars of the Grey Tinsel live in a close symbiotic relationship with these ants, and are always accompanied by ants during both feeding and movement on the host plant. The caterpillars also rest between feeding sessions within the confines of an ant pavilion. Moulting and pupation also typically take place in ant pavilions.

Local host plant #1: Sonneratia ovata.

Local host plant #2: Avicennia rumphiana.

Eggs are usually laid singly on a stem or the underside of a leaf of the host plant. At times, more than one egg can be found together. Each egg is whitish with a slight greenish undertone when freshly laid. It has a flattened bun shape with a base diameter of about 0.9mm. The egg surface is adorned with numerous tiny pits with the micropylar sitting atop.

A female Grey Tinsel attempting to oviposit on the underside of a leaf on a Sonneratia ovata tree.

An egg of the Grey Tinsel laid on a stem of Sonneratia ovata.

Two eggs of the Grey Tinsel laid in an old bite mark on a leaf of Sonneratia ovata.

Two close-up views of an egg of the Grey Tinsel on the day of oviposition.

A fully developed egg of the Grey Tinsel with the top of the egg shell already nibbled away by the soon-to-emerge caterpillar.

It takes about 3.5-4 days for the egg to hatch. The young caterpillar consumes just enough of the egg shell to emerge. It is pale yellowish brown in ground color, and has a length of about 1.3mm. The dorsum is reddish brown in the prothorax and the abdomen except for the 6th abdominal segment. The prothorac shield is dark brown in colour and the anal plate is greyish brown. Long setae (hairs) run along the length of the body dorso-laterally as well as sub-spiracularly. Pairs of short black setae also occurs on the dorsum. A number of very tiny whitish mushroom-like setae are also featured on the body surface. After emergence, the young caterpillar does not devour the remnant of the egg shell, but proceed to feed on stem surface or leaf lamina nearby.

A newly hatched caterpillar of Grey Tinsel next to its empty egg shell, length: 1.3mm.

Two views of a newly hatched caterpillar of the Grey Tinsel, length: 1.3mm.


A 1st instar caterpillar of the Grey Tinsel being attended by ants.

In all seven instars of its larval stage, the caterpillars of the Grey Tinsel feed by grazing on the leaf surface and on stem surface. The 1st instar caterpillar also has a fondness for feeding on the dark brownish edge of old bite marks on leaf surface. The 1st instar lasts about 5 days with the body length increased to about 1.9-2.0mm.

A 1st instar caterpillar of the Grey Tinsel feeding within an old bite mark on the leaf surface of Sonneratia ovata.

Two views of a 1st instar caterpillar of the Grey Tinsel, feeding on stem surface, length: 2mm.

Two views of a late 1st instar caterpillar of the Grey Tinsel, dormant prior to the moult to the next instar.

The 2nd instar caterpillar is mostly similar to the 1st instar caterpillar with a few exceptions. Now both prothoraic shield and anal plate are more prominently black in colour, and the pairs of black setae on the dorsum are longer in proportion. The body surface is also adorned with many tiny black and white mushroom-like setae. On the dorsum of the 7th abdominal segment, the dorsal nectary organ is already present. Likewise, tentacular organs on the 8th abdominal segment are discernible. The 2nd instar lasts for about 5 days, with the body length reaching up to 2.7-2.8mm.

Two views of an early 2nd instar caterpillar of the Grey Tinsel, length: 1.8mm.

A newly moulted 2nd instar caterpillar of the Grey Tinsel, eating its old skin.

Two views of a 2nd instar caterpillar of the Grey Tinsel, length: 2.5mm.

A 2nd instar caterpillar of the Grey Tinsel receiving attention from an ant.

Two views of a 2nd instar caterpillar, late in this stage, dormant prior to its moult.

The 3rd instar caterpillar mostly resembles the 2nd instar caterpillar but with a greater spread of small black mushroom-like setae on the body surfaces. The reddish brown area on the prothorax is also reduced in size around the black prothoracic shield. The reddish band at the 3rd abdominal segment is somewhat narrower compared to that in the previous instar. After about 5 days in the 3rd instar, and the body length reaches up to about 4.1-4.5mm, the caterpillar moults to the next instar.

Two views of a newly moulted 3rd instar caterpillar of the Grey Tinsel.

Two views of a 3rd instar caterpillar of the Grey Tinsel, length: 4.1mm.

A 3rd instar caterpillar of the Grey Tinsel, with an ant riding on it, note the presence of several small scale insects around the caterpillar.

Two views of a late 3rd instar caterpillar of the Grey Tinsel, dormant prior to its moult to the next instar.

The 4th instar caterpillar resembles the 3rd instar caterpillar but with some changes. The reddish brown dordsal bands shrink at several places, with the part at the 3rd abdominal segment almost all disappeared, and the anal plate almost without any reddish brown patches surrounding it. In the prothorax, the anterior border of the black prothoracic shield is almost free of any reddish brown coloration. The dorsal nectary organ on the 7th abdominal segment and the tentacular organs on the 8th abdominal segment are now easily discernible. The 4th instar lasts about 5 days with the body length reaching up to 5.6-6.0mm.

Two views of a newly moulted 4th instar caterpillar of the Grey Tinsel, resting next to its old skin and head capsule.

Two views of a 4th instar caterpillar of the Grey Tinsel, length: 4.8mm.

A 4th instar caterpillar of the Grey Tinsel feeding at an old bite mark whilst being attended by a group of ants.

A 4th instar caterpillar of the Grey Tinsel taking shelter in an ant pavilion.

Two views of a late 4th instar caterpillar of the Grey Tinsel, dormant prior to the next moult.

The 5th instar caterpillar resembles the 4th instar caterpillar in most body features/markings. The reddish brown dorsal bands now have more wavy outlies, and there are more clusters of dark spots on the body surface. The dorsum on the 6th abdominal segment features two narrow dorso-lateral bands of tiny black spots linking the dorsal band terminating at the 5th segment and the one starting from the 7th segment. The 5th instar lasts about 6 days with the body length reaching up to 7.5-8mm.

Two views of a newly moulted 5th instar caterpillar of the Grey Tinsel, next to its old skin and head capsule.

Two views of a 5th instar caterpillar of the Grey Tinsel, length: 6.9mm.

A 5th instar caterpillar of the Grey Tinsel feeding on the leaf surface (on Sonneratia ovata) whilst being attended by a group of ants.

A caterpillar of the Grey Tinsel found on a stem of Api-api bulu, in the presence of ants and scale insects.

Two views of a late 5th instar caterpillar of the Grey Tinsel, dormant prior to the next moult.

The 6th instar caterpillar resembles the 5th instar caterpillar closely. The dorsum of the metathorax and the 6th abdominal segment now has a central reddish brown patch, and the anterior part of the prothoracic shield has three short reddish brown bands radiating forward. Dorso-laterally and lateraaly, the body has clusters of black to dark greenish patches. Towards the end of the instar, the pale yellowish brown border of the dorsal brown patch becomes increasingly pale yellowish to whitish. The 6th (and penultimate) instar lasts about 8 days with the body length reaching up to 11.2 to 11.8mm.

Two views of a newly moulted 6th instar caterpillar of the Grey Tinsel, eating its old skin.

Two views of a 6th instar caterpillar of the Grey Tinsel, early in this stage, length: 8.5mm.

A 6th instar caterpillar of the Grey Tinsel feeding in an old bite mark whilst being attended by a group of ants.

Two views of a 6th instar caterpillar of the Grey Tinsel, length: 11.8mm.

Two views of a late 6th instar caterpillar, dormant prior to the next moult.

The 7th instar caterpillar resembles the late 6th instar caterpillar closely. Small narrow strips of pale yellowish brown patches appear within the reddish brown dorsal bands giving the bands a more striking appearance. As growth progresses in this final instar, the body base colour varies from pale yellowish brown to pale reddish brown in the last 2-3 days. The 7th (and final) instar lasts about 9 days with the body length reaching up to 13.5mm.

Two views of a newly moulted 7th instar caterpillar of the Grey Tinsel, eating its old skin.

Two views of a 7th instar caterpillar of the Grey Tinsel, early in this stage, length: 10mm.

Two views of a 7th instar caterpillar of the Grey Tinsel, length: 12.5mm.

Two views of a 7th instar caterpillar of the Grey Tinsel, partially hidden in an ant pavilion.

Two views of a 7th instar caterpillar of the Grey Tinsel, late in this stage, length: 12.5mm.

A late 7th instar caterpillar of the Grey Tinsel sighted in the field.

As it enters the pre-pupatory phase of its life cycle, the caterpillar ceases its feeding activity and its body gradually shrinks in length. The dorsal bands turns dark greenish at the same time. In the wild, the caterpillar typically picks a spot in an ant pavilion for the pupation site. But in captive breeding and with the absence of an ant pavilion, the pupation site is usually the underside of a leaf. At the chosen site, it stays dormant for about 1 day before spinning a silk girdle and a silk pad to which it attaches itself via claspers at the posterior end.

Two views of an early pre-pupa of the Grey Tinsel.

Two views of a late pre-pupa of the Grey Tinsel.

Two views of a fresh-pupa of the Grey Tinsel.

Two views of a one-day old pupa of the Grey Tinsel.

About 0.5 day after the pre-pupatory caterpillar secures itself to the pupation spot, pupation takes place. The pupa is secured with the silk girdle around the wing pad and the cremastral attachment. The pupa has the typical shape of a lycaenid pupa. It is dark yellowish brown with scattered dark brown to black patches on its surface. Length of pupa: 8.0 to 8.5mm.

A pupa of the Grey Tinsel sighted in the wild partially hidden in an ant pavilion.

Another pupa of the Grey Tinsel sighted in the wild partially hidden in an ant pavilion.

Two views of a pupa of the Grey Tinsel.

Two views of a mature pupa of a male Grey Tinsel.

Two views of a mature pupa of a female Grey Tinsel.

The pupal period of the Grey Tinsel is 10 days for the female and 11 days for the male. The day before eclosion, the pupa becomes darkened in color signaling the imminent emergence of the adult. The coloration of the wind pad at this stage reveals the gender of the adult. The next day the adult butterfly emerges from the mature pupa.


Video: A female Grey Tinsel emerges from its pupal case.

A newly eclosed Grey Tinsel resting on an ant pavilion with its pupal case partially hidden in the pavilion.

References:
  • [C&P5] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, G. and N.  van der Poorten (Eds.), 5th Edition, Malayan Nature Society, 2020.
  • Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012.
  • A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2nd Edition, 2015.
Acknowledgment:
I would like to express my gratitude to Lim Hanpeng, Timothy Liew, Loh Jian Kai and Zick Soh for sharing information on early stages of the Grey Tinsel.

Text by Horace Tan, Photos by Low Jian Kai, Lim Hanpeng, Loh Mei Yee, Zick Soh, Khew SK and Horace Tan, Videos by Lim Hanpeng, Loh Mei Yee and Horace Tan.

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