Butterflies of
Thailand, Malaysia &
Borneo
Malayan Egg-fly
Hypolimnas anomala
WALLACE, 1869
Family - NYMPHALIDAE
subfamily -
NYMPHALINAE
Tribe - JUNONIINI
introduction
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habitats |
lifecycle |
adult behaviour
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Hypolimnas anomala,
male, Bukit Tapah,
West Malaysia |
Introduction
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The "Egg-fly" - a butterfly which stands guard
over its eggs until they hatch.
Hypolimnas anomala and
its "sister species" antilope
are a fascinating pair of butterflies which have a unique
way of protecting their offspring. They lay their eggs in
large batches on the upper surface of leaves, and then stand
guard over them, forming a protective umbrella to shield
them from parasitoid wasps. They remain in this position
until the eggs hatch and the tiny caterpillars have
dispersed several days later. Quite how this behaviour came
to "evolve" is a mystery which no one seems able to
answer..... |
The genus Hypolimnas comprises of
about 27 species, of which 12 are restricted to the Afrotropical
region ( including 2 Madagascan endemics ). Most of the
remainder are found in various parts of the Oriental and
Australian regions. The exception is
misippus, which has a huge range encompassing Florida (
USA ), the Caribbean islands, northern South America, most of
Africa, much of tropical and subtropical Asia from India to
Japan, and south across Malaysia, Indonesia and Papua to
Australia.
Many members of
the genus are marked with large colourful patches of blue, white
or orange, and are
Batesian mimics of the Danainae
- a subfamily of butterflies demonstrated to be unpalateable or
poisonous to birds. The female of
Hypolimnas misippus for example is a perfect mimic in
colour, pattern and behaviour of the Plain Tiger
Danaus chrysippus; while the female
of Hypolimnas bolina is a mimic of
the Common Crow Euploea core.
Hypolimnas anomala is another
Euploea mimic. The female, which
has a dazzling iridescent purple-blue sheen across the outer
half of the forewings,
mimics the
male of Euploea mulciber, not only
visually, but in terms of the microscopic structure of it's wing
scales ( Saito, 2002 ). The male, as illustrated above, is more
of a general purpose mimic - a bird could easily mistake it for
any of the plainer Euploea species.
Hypolimnas anomala is found in
Thailand, peninsular Malaysia, Singapore, Sumatra, Borneo, Java,
Sulawesi, Timor, the Philippines, and around Darwin in northern
Australia.
Habitats
The Malayan
Egg-fly is found in lowland rainforests at altitudes between sea
level and about 300m, often in disturbed areas around forest
villages.
Lifecycle
The
greenish-white eggs are barrel-shaped, with 14 prominent
vertical ribs. They are laid in large batches on the upperside
of leaves of the foodplants, which include
the flowering herb Pipturus
and probably other genera of Urticaceae.
The
caterpillars are gregarious during their early instars, and feed
diurnally. They are blackish in colour, with pale lines along
the back and sides, and are covered in short multi-branched
spines. When fully grown the larva is black, with a bright red
head which bears a pair of long bristly black spines. Each body
segment is armed with 6 bright orange multi-branched spines with
conical bases.
The chrysalis
is pale brown, with short spikes along its back, and in shape is
similar to that of the Checkerspots and Fritillaries. It is
suspended by the cremaster from a stem or from the underside of
a leaf.
Adult behaviour
Males of this
common species can often be seen walking about on damp ground,
rapidly fanning their wings as they probe around for moisture.
This instantly distinguishes them from
Euploea males, which are also commonly seen on the
ground, but always hold their wings erect when feeding, and are
attracted to carrion and rotting fruit, rather than bare ground.
Both sexes of
anomala ( and other
Hypolimnas species) also visit
Lantana and many other flowers for
nectar. When not feeding they tend to spend long periods at rest
on the foliage of bushes.
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