Butterflies of
Thailand, Malaysia &
Borneo
Golden-eye
Euripus nyctelius
DOUBLEDAY, 1845
Family - NYMPHALIDAE
subfamily -
APATURINAE
Tribe - APATURINI
introduction
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habitats |
lifecycle |
adult behaviour
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Euripus nyctelius,
male, Taman Negara,
West Malaysia |
Introduction
The Golden-eye, also known as the Courtesan, is one of 3 members
of the genus Euripus, which is
placed in the Apaturini - the same tribe to which the
Purple Emperor of Europe
belongs.
The male, illustrated above, is regarded as a Batesian mimic of
the male of Euploea radamanthus, a
Danaine which has a similar pattern of white rays in its
underside. This Danaine, known as the Magpie Crow, has been
demonstrated to be toxic to birds, and is mimicked by several
non-toxic butterflies including nyctelius
and the Papilionid Chilasa paradoxa.
The female of nyctelius produces 2
distinct forms or morphs - f. isina,
on the upperside is marked with white bars on a black ground
colour, again just like the
male
of Euploea radamanthus. Another of
the nyctelius female morphs is
euploeoides, which as its name
suggests is also a Euploea mimic,
but in this case it is imitating the
female
of radamanthus, which has extensive
areas of white on its hindwings. Both sexes of
nyctelius possess distinctive
golden-yellow eyes.
Euripus nyctelius is found in
Sikkim, Myanmar, Thailand, West Malaysia, Singapore, the
Philippines, Sumatra, Borneo and Java - a range that coincides
exactly with that of Euploea radamanthus.
Habitats
This species is found in primary rainforest at elevations
between sea level and about 500 metres.
Lifecycle
I have no information about the egg stage, but based in related
genera it is likely to be spherical and laid singly on leaves of
the foodplant.
The caterpillar is green with a series of pale diagonal stripes
along the sides. It is plump, and tapers strongly towards the
tail. The head is armed with a pair of forward curving horns. It
feeds nocturnally on the "Gunpowder tree"
Trema orientalis ( Cannabaceae ).
The chrysalis
is pale green with whitish diagonal stripes along the sides, and
bears a remarkable resemblance to a leaf, complete with a
"midrib" and "veins". It is suspended by the cremaster from
beneath a leaf of the foodplant.
Adult behaviour
Males are not
uncommon but are elusive in behaviour. They tend like other
Apaturini to spend most of their time high on territorial
perches in the tree tops, and give chase to any other males
which enter their domain. Occasionally they descend to imbibe
mineralised moisture from pebble-strewn sandbanks.
Females are
seen much less frequently, and usually observed in flight around
low vegetation.
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