18 January 2014

Life History of the Chocolate Demon

Life History of the Chocolate Demon (Ancistroides nigrita maura)

Butterfly Biodata:
Genus: Ancistroides Butler, 1874
Species: nigrita Latreille, 1824
Sub-species: maura Snellen, 1880
Wingspan of Adult Butterfly: 42-50mm
Caterpillar Local Host Plants: Etlingera elatior (Zingiberaceae, common name: Torch Ginger), Hedychium coronarium  (Zingiberaceae, common name: White Ginger Lily, Butterfly Ginger), Zingiber officinale (Zingiberaceae, common name: Ginger), Alpinia aquatica (Zingiberaceae).

Physical Description of Adult Butterfly:
Chocolate Demon is a relatively large skipper. On the upperside, the wings are dark brown and unmarked. On the underside, the wings are brown with marginal areas of both wings paler than the ground colour. The proboscis is particularly long compared to other skipper species.

Field Observations of Butterfly Behaviour:
Chocolate Demon is moderately common in Singapore. The adults are typically found in parks, park connectors and gardens where one of its host plants in the Zingiberaceae is cultivated. The adults fly in an erratic and hopping manner amongst low shrubbery. They visit flowers for nectar, and puddle on birding droppings and other animal excretions.

Early Stages:
The early stages of Chocolate Demon are polyphagous with its recorded host plants belonging to the Zingiberaceae family. The caterpillars feed on the leaves of the host plants, and live in leaf shelters constructed by cutting, folding and securing leaf fragments with silk threads.

Local host plant: Etlingera elatior (Torch Ginger).

The eggs of the Chocolate Demon are laid singly on the under surface of a leaf or the stem of the host plant. The dome-shaped egg is milky white with very fine longitudinal striations. It has a base diameter of about 1.25mm.

Two views of an egg of the Chocolate Demon.

Left: mature egg with portion of the egg shell already devoured; Right: remnant of the egg shell after the emergence of the caterpillar.

The egg takes about 4-5 days to hatch. The newly hatched has a length of about 3.2mm and has a black head capsule and a whitish body. A few relatively long setae adorns the posterior end. A black collar mark is present in the prothoracic segment.

Two views of a newly hatched caterpillar of the Chocolate Demon.

After hatching, the young caterpillar eats the remaining egg shell for its first meal, and then moves on to construct its first leaf shelter, typically at the leaf tip or the leaf edge. From the shelter, it then ventures out to eat the nearby leaf lamina for subsequent meals. The body takes on a green undertone as a result. The growth in this first instar is moderately paced and the body length reaches about 6.5mm in about 5 days before the moult to the 2nd instar.

Two views of a 1st instar caterpillar, length 6.2mm.

A late 1st instar caterpillar, dormant prior to its moult, length: 6.5mm.

The 2nd instar caterpillar is yellowish green in body colour. The head capsule is still black, but the black collar mark on the prothorax is now absent. At the posterior end, the relatively longer setae are longer present. This instar lasts about 4 days with the body length reaching 10.5-11.5mm.

Two views of a 2nd instar caterpillar, late in this stage, length 9mm.

A late 2nd instar caterpillar, dormant prior to its moult, length 11.5mm.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely. This instar takes about 4 days to complete with body length reaching about 17.5-21mm.

Two views of a 3rd instar caterpillar, length 16.5mm.

A late 3rd instar caterpillar, dormant prior to its moult, length: 17.5mm.

The only obvious change seen in the 4th instar caterpillar is the whitish ground colour of its body, and many tiny circular green speckles dotting the body surface. This instar takes about 5 days to complete with body length reaching about 28-31mm.

Two views of a 4th instar caterpillar, early in this stage, length 18mm.

Two views of a 4th instar caterpillar, later in this stage, length 24mm.

A late 4th instar caterpillar, dormant prior to its moult, length: 29.5mm.

The 5th and final instar caterpillar assumes a stronger tone of white in its body colour and more prominent speckled appearance compared to the 4th instar. The head capsule is dark brown to black with the paler brown patches occurring laterally in some specimens. This instar lasts for about 6-7 days, and the body length reaches up to 48-51mm.

Two views of a 5th instar caterpillar, early in this stage, length 29mm.

Two views of a 5th instar caterpillar, length 40mm.

Two views of a 5th instar caterpillar, late in this stage, length: 51mm.

On the last day of the 5th instar, the body of the caterpillar shortens and changes to a translucent shade of pale green. It ceases feeding and comes to a halt on the under surface of a leaf of the host plant. Here the caterpillar spins a short transverse silk band and a silk girdle. At the same time, a moderate amount of white waxy substance is secreted by the caterpillar and spread over the pupation site. With its posterior end secured to the silk band via claspers and the body secured at the mid-section with the girdle, the caterpillar enters its immobile pre-pupatory stage.

A pre-pupatory larva of the Chocolate Demon.

Pupation takes place about 1.5 days later. The yellowish green pupa secures itself with the same silk girdle as in the pre-pupal stage, but with the cremaster replacing claspers in attaching the posterior end to the transverse silk band. The long and slender pupa has a moderately long and pointed rostrum, and is unmarked. It features a long proboscis tube extending well beyond its posterior end. Length of pupae: 37-39mm or 60-62mm if the proboscis tube is included in the measurement.

Two views of a pupa of the Chocolate Demon.

Two views of a mature pupa of the Chocolate Demon.

After about 8 days of development, the pupa turns black in the thorax and wing cases as its skin turns translucent with the development within the pupal case coming to an end. The following day, the adult butterfly emerges from the pupal case.

A newly eclosed Chocolate Demon resting next to its empty pupal case.

  • [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, 2010.

Text by Horace Tan, Photos by Simon Sng, Chng CK, Loke PF, Federick Ho and Horace Tan

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