Life History of the White Tipped Skipper

Life History of the White Tipped Skipper (Erionota acroleuca apicalis )

Butterfly Biodata:
Genus: Erionota Mabille, 1878
Species: acroleuca Wood-Mason & de Nicéville, 1881
Sub-Species: apicalis Evans, 1932
Wingspan of Adult Butterfly: 58-62mm
Caterpillar Local Host Plant: Caryota mitis (Arecaceae; common name: Fishtail Palm).

A male White Tipped Skipper taking off from its perch, giving a view of the upperside of its forewing and whitish wing tip.

The upperside view of a newly eclosed male White Tipped Skipper, showing the whitish wing tips of the forewings.

Physical Description of Adult Butterfly:

The eyes are red. On the upperside, the wings are dark brown. The forewing has three large, yellowish hyaline spots in spaces 2, 3 and cell-end, whereas the hindwing is unmarked. In the male, the forewing has a whitened apical patch (which is absent in the lookalike species: E. torus and E. thrax ). On the underside, the wings are paler brown with the upper half of the forewing and the entire hindwing dusted with pale buff.

The upperside view of a newly eclosed female White Tipped Skipper.

Field Observations of Butterfly Behaviour:

The White Tipped Skipper is moderately rare in Singapore. It is the smallest of the three lookalike Erionota species in Singapore. The adults are fast fliers and are usually found in dark and shady corners of vegetation in  the nature reserves, hill parks and coastal wetlands. They have the habit of perching with closed wings and could be hard to spot in the shady habitat they inhibit. The immature stages of White Tipped Skipper are easier to find than the adults.  

Early Stages:

The White Tipped Skipper has so far been found to breed on one palm species locally: Caryota mitis (Fishtail Palm), a very common palm found in many habitats in Singapore. The caterpillars feed on leaves of the host plant, and live in shelters formed by folding a leaf blade from one edge.

Local host plant: the Fishtail Palm.

The eggs are laid singly on the surface of a leaf of the host plant. Each dome-shaped egg is reddish/orangy brown with a basal diameter of about 2-2.1mm. The micropylar sits atop with a number of fine and whitish ridges running longitudinally from it.

Two views of an egg of the White Tipped Skipper.

Two views of a maturing egg, with the black head capsule distinguishable through the egg shell.

It takes about 5-6 days for the egg to hatch. The young caterpillar eats just enough of the shell to emerge, and has a length of about 5mm. Its cylindrical body is yellowish, and has a number of moderately long, whitish setae running laterally. The head capsule is black and right behind it a black collar mark is present on the prothorax. The newly hatched nibbles away most of the egg shell remnant before proceeding to construct its first leaf shelter.

The newly hatched caterpillar in its partially completed shelter.

The body turns yellowish green after the caterpillar has a few sessions of the leaf diet. By the time the caterpillar lies dormant for its moult to the 2nd instar, its length has reached 9.6-10mm. The 1st instar takes about 3 days to complete.

Two views of a 1st instar caterpillar, length:9.6mm.

The 2nd instar caterpillar still has a yellowish green body, and the head capsule is dark reddish brown. The black collar mark on the prothorax has faded almost entirely. As it grows in this instar, the body excretes a white powdery substance which coats the body surface on almost all body segments. This instar lasts about 3-4 days with the body length reaching about 15mm.

Two views of a 2nd instar caterpillar, newly moulted, length: 7.8mm.

Two views of a 2nd instar caterpillar, late in this stage, length: 14.5mm.

The 3rd instar caterpillar still has a dark reddish brown head capsule with the body colour more whitish compared to the 2nd instar. There is no longer any trace of the black collar mark on the prothorax. The amount of whitish substance covering the body surface has become thicker. This instar lasts about 4-5 days with the body length reaching about 22-23mm.

Two views of a 3rd instar caterpillar, early in this stage, length: 15mm.

Two views of a 3rd instar caterpillar, late in this stage, length: 21.5mm.

The 4th instar caterpillar closely resembles the 3rd instar caterpillar. Just about all body segments are covered in the white substance in this instar. This penultimate instar lasts about 5-6 days with the body length reaching up to 32-35mm.

Two views of a 4th instar caterpillar, early in this stage, length: 22.5mm.

Two views of a 4th instar caterpillar, late in this stage, length: 28mm.

The 5th instar caterpillar is little changed from the 4th instar caterpillar. The body is almost all whitish (without the white substance), and soon after the moult, the entire body is covered evenly with a thick layer of the white powdery substance. The head capsule is initially orangy, but turn reddish brown and eventually dark brown within a few hours after the moult. This final instar takes about 7-8 days to complete with the body length reaching 51-53mm.

Two views of a 5th instar caterpillar, newly moulted, length: 31mm.

Two views of a 5th instar caterpillar, length: 41mm.

Two views of a 5th instar caterpillar, length: 51mm.

Towards the end of 5th instar, the body of the caterpillar shortens in length and body colour assumes a uniform shade of creamy yellow. The fully grown caterpillar stays within its last shelter and excretes a copious amount of the whitish substance to line the interior wall of the shelter. Within the shelter, it constructs a transverse silk band near its posterior end. Once the caterpillar attaches its claspers to the silk band, it enters the dormant prepupatory phase which lasts about one day.

Two views of a dormant pre-pupa of  the White Tipped Skipper.

The pupa secures itself with its cremaster attached to the transverse silk band. It has a short thorax and a rather long abdomen. The body is creamy yellow and has a slight greenish tinge in the thorax and wing case. The pupa body is coated with the white substance transferred through contact with the shelter wall. Length of pupae: 33.5-36.5mm.

Two views of a pupa of the White Tipped Skipper.

After 8-10 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 the White Tipped Skipper.

A newly eclosed White Tipped Skipper.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society, 1992.
• 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.

Text and Photos by Horace Tan.