03 March 2012

Life History of the Dark Tit

Life History of the Dark Tit (Hypolycaena thecloides thecloides)

Butterfly Biodata:
Genus: Hypolycaena C & R Felder,1862
Species: thecloides
C & R Felder,1860
Sub-species: thecloides
C & R Felder,1860
Wingspan of Adult Butterfly:26-30mm
CaterpillarLocal Host Plant:
Flagellaria indica (Flagellariaceae).

A sunbathing  Dark Tit  displaying its upperside.

Physical Description of Adult Butterfly:
Above, both sexes are dark brown except for an orange tornal area stretching to space 3 on the hindwing. Prominent black spots are embedded in the orange tornal area in spaces 1b and 2 and within the whitish area in space 1a. Underneath, both sexes are whitish grey with  acell-end bar and a narrow orange post-discal line on both fore- andhindwings.  The forewing apical area, costal margin and termen are shaded in orange.The hindwing has an orange tornal area up to space 3 and a prominent black spot embedded in space 2. Another equally large black spot is featured on the whitish tornal lobe. A prominent orange bar could be found at the base of space 7 in the hindwing. There are two white-tippedtails at ends of veins 1b and 2, with the longer one at vein 1b. Theupperside of the abdomen is colored as per wing upperside, but theunderside is mostly white. The legs are also whiteand black-banded.

Field Observations of Butterfly Behaviour:
This species is moderately rare in Singapore. It can be found in the Central Catchment Reserve, certain wastelands as well as  landward edges of mangrove areas in both the main Singapore island and offshore islands like Pulau Ubin and Pulau Semakau. At times, the adults have been found to  occur in numbers locally at one location. The fast flying adults typically perch with its wings closed upright between flights. In sunny weather, however, they have the tendency to sun-bathe with wings fully open.

Early Stages: 
The Dark Tit is likely to be monophagous as only one host plant has been recorded both locally and across the region. Its host plant, Flagellaria indica, is  a monocotyledon. This is  remarkable  as the majority of  Lycaenidae species feed on dicotyledons.  Also noteworthy is that the same host plant is recorded in Igarashi and Fukuda's voluminous work: Life History of Asian Butterflies, vol. 2, but with the plant wrongly identified as a gramineae species. The caterpillars of the Dark Tit feed on the leaf blades and young/immature stems of the host plant, and  are attended by several ant species.

Host plant: Flagellaria indica.

Three eggs of the Dark Tit found on the host plant in a wetland reserve.

The eggs are laid singly on leaf underside or on the stem of the host plant. Each egg is about 0.7-0.75mm in diameter, white in color with a greenish undertone when freshly laid. It is dome-shaped with a depressed micropylar at the pole.  Large triangular  indentations with rather broad ridges are featured on the egg surface.

Two views of an egg of the Dark Tit.

A sequence of 4 snapshots  of egg development.
It takes about 3 days for the egg to hatch. The pale yellowish brown newly hatched has a length of about 1-1.1mm. Its head and the rather large pro-thoracic shield are in the same coloration as the body ground colour. The body also features rather long, pale yellowish brown  dorso-lateral and lateral setae (hair).  The newly hatched shows no interest in devouring the remnant of the egg shell after its emergence, and moves straight away to nibble on the leaf lamina in its vicinity. The caterpillar typically leaves a feeding trail  marked with foliage/tissue damage and frass pellets.

Two views of a newly hatched caterpillar of the Dark Tit.

An early 1st instar caterpillar  feeding  on the stem of its host plant (near center of pic).

As it grows, the body color becomes more yellowish.  After about 3-4 days of growth in the first instar, and reaching a length of about 2.4mm,the caterpillar moults to the next instar. Unlike its  cousin, the Common Tit (Hypolycaena erylus teatus), the Dark Tit caterpillars consume the exuvia after each moult.

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

Two views of a 1st instar caterpillar, dormant before its moult.

The 2nd instar caterpillar has numerous pale brown setae over its body, with those occurring dorso-laterally and laterally somewhat longer than the rest. Depending on whether it is feeding on the yellowish brown stem or the green leaf blades, the caterpillar appears to occur in two colour forms: yellowish brown throughout or yellow with a strong green undertone.  Even at this early stage, the dorsal nectary organ is discernible on the dorsum of the 7th abdominal segment. The 2nd instar caterpillar reaches a length of about 4.5-4.8mm, and after about 3 days in this stage, it moults again.

Two views of a 2nd instar caterpillar, early in this stage, length: 2.2mm..

Two views of a 2nd instar caterpillar, late in this stage, length: 4.2mm.

Two views of a 2nd instar caterpillar, dormant before its moult, length: 4.1mm.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely. One discernible difference is that the numerous setae covering the body are now proportionately shorter and uniform in length. The dorsal nectary organ is also rather large and  prominently featured. However the pair of tentacular organs found on the 8th abdominal segment in most of the other Lycaenidae species are not observed in the Dark Tit, in this and later instars. The 3rd instar takes about 2-3 days to complete with the body length reaching about 6.5mm.

Two views of a 3rd instar caterpillar feeding on the stem tissue, length: 5.5mm

Two views of a 3rd instar caterpillar, late in this stage, length: 6.2mm.

The 4th instar resembles the late 3rd instar caterpillar closely with no obvious changes.  The 4th instar takes about 3 days to complete with the body length reaching about 11mm.

Two views of a 4th instar caterpillar, early in this stage, length: 6.5mm.

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

A Dark Tit caterpillar feeding on the stem of the host plant.
Note the attending ant and the pile of frass pellets.

The 5th instar caterpillar is again little changed in body features from the earlier two instars. In comparison, its body colour is mainly green. Its dorsal nectary organ seems to be rather  active with droplets of nectary fluid being exuded from time to time.

A newly moulted 5th instar caterpillar of the Dark Tit.

Two views of a 5th instar caterpillar, length: 13.5mm.

Two views of a 5th instar caterpillar, late in this stage, length: 17mm.

A 5th instar caterpillar devouring stem issue in a wetland reserve. Note the attending ant and the fluid droplet on the dorsal nectary organ.

After about 3 days of feeding and reaching a length of about 17mm, the caterpillar stops foodintake, and its body gradually shortened and decolorised to a uniform lime green.  The caterpillar would wander around in seek of a pupation site which is typically a spot on the leaf surface. At this site, the pre-pupatory caterpillar prepares for pupation by spinning a silk girdle and a silk padto which it attaches itself via its anal claspers.  After 1 day as apre-pupa, pupation takes place. The pupa has a typical but stout Lycaenid shape. It is predominantly pale greenand unmarked. Pupal length: 8.5-10mm. 

Two views of an immobile pre-pupa of the Dark Tit.

Two views of a pupa of the Dark Tit.

Seven days later, the pupa turns rather dark, first in the wing pad and thorax,then progressively in the abdomen. The next day, the pupal stage comes to an end with the emergence of the adult butterfly.

Two views of a mature pupa of the Dark Tit.

A newly eclosed  Dark Tit waiting for its wings to expand fully near its pupal case.


  • [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, The Malayan Nature Society.
  • Life Histories of Asian Butterflies, Volume 2, S. Igarashi & H. Fukuda, Tokai University Press, 2000.
  • Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006.

Text by Horace Tan, Photos by Wong C M, Loke PY, Chng CK, Nelson Ong  and Horace Tan