Butterflies of
Malaysia and Borneo
Rajah Brooke's
Birdwing
Trogonoptera brookiana
WALLACE, 1855
Family -
PAPILIONIDAE
subfamily -
PAPILIONINAE
Tribe - TROIDINI
introduction
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habitats |
lifecycle |
adult behaviour
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Rajah Brooke's
Birdwing Trogonoptera brookiana albescens,
West Malaysia |
Introduction
The magnificent
Rajah Brooke's Birdwing was discovered on Borneo in 1855 by the legendary
explorer and naturalist
Alfred Russell Wallace.
It is widely distributed throughout Borneo, Sumatra, Palawan and the central
states of West Malaysia, and in a few areas is very abundant, but populations
are quite localised. It also occurs as a scarce species in Thailand.
Sadly the butterflies are killed in vast numbers, mainly by Orang Asli children, paid a
pittance for the dead specimens by dealers who sell them on to gift shops. The
majority are badly damaged because the children are unskilled with
butterfly nets, and often use crude methods of killing - sometimes the butterflies
are attracted to a sticky "bait" which glues their wings to the ground, or
sometimes they are killed by throwing small stones
at them.
The
subspecies trogon,
which occurs on peninsular Malaysia in Johore state, and also on Sumatra and
Palawan, differs slightly in appearance and behaviour from albescens,
and is considered to be a separate species by some taxonomists.
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Rajah Brooke's
Birdwing Trogonoptera brookiana albescens,
West Malaysia |
Habitats
In West Malaysia the butterfly occurs in tropical rainforest habitats at
altitudes from sea level to about 800 metres. From personal observations I
believe the butterflies breed mainly at altitudes above 300 metres, but that the
males are more often encountered at much lower elevations, when they descend to
imbibe mineralised moisture from seepages or sulphur springs. At Ulu Gerok in
Perak for example they occur commonly in oil palm plantations where the larval
foodplants are absent, although they are found in greater numbers in the
relatively untouched hill forests above. Females are rarely seen, and probably
spend most of their lives in the tree tops.
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Rajah Brooke's
Birdwing Trogonoptera brookiana albescens,
male at rest on tree fern |
Lifecycle
The globular reddish eggs are laid singly on the leaves of climbing vines of the
genus
Aristolochia.
The
fully grown caterpillar is dark greyish brown, with a light grey saddle mark on
the back. The body is adorned with buff and grey tubercles along the back and
sides. As with other members of the Papilionidae the larva is equipped with an
eversible forked structure ( osmaterium ) behind the head, which secretes a
pungent fluid that deters ants, wasps and other predators.
The
pupa is apple green, marked with violet, and is attached vertically by the
cremaster and a silk girdle, to a vine stem.
Adult behaviour
The butterflies are powerful
flyers, capable of travelling from one side of a river to the
other with no more than 3 or 4 wing-beats.
Males congregate at hot sulphur
springs, seepages and other sources of minerals. They glide
slowly in tight circles when about to settle, spiralling
gracefully down to the ground. Immediately after alighting the
butterflies nervously flutter their wings for a few seconds but
soon settle with the wings outspread, always with the forewings
swept back, half covering the hindwings.
This "mud-puddling" behaviour occurs throughout the day, and often
continues until dusk.
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part of a group
of 100 males seen at Ulu Gerok |
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In
May 2009 at Ulu Gerok I came across one of the most stunning
butterfly spectacles I have ever seen - a massive group of over
100 pristine Rajah Brooke's Birdwings settled on a small patch of
ground on a quiet forest track. No photograph, video clip or words
can begin to do justice to the incredible beauty of these
creatures, and to see such a huge aggregation was a sight
guaranteed to blow the mind of the most experienced butterfly
enthusiast.
Try to imagine 100 butterflies, each measuring over 7 inches
across, a quivering mass of shimmering iridescent green wings,
packed together on a patch of ground the size of a small dining
table. Then try to imagine the thrill of being so close that you
could reach down and touch them. After taking a few photographs
you edge gently away but the whole group erupts into flight, and
you are surrounded by a swirling mass of glittering green wings.
You freeze on the spot, hoping not to scare them away, and they
respond by gliding closely around you. Then one by one they
resettle on the ground until they encircle you. At first they
nervously quiver and flutter, but after a couple of minutes they
all relax and spread their glorious wings. You are mesmerised, and
the huge privilege of such an experience is something you never
forget. |
In
Sabah the butterflies once assembled in vast numbers at Poring hot
springs, but most of the area where the butterflies congregated
has now been built on. In the Danum
valley of Sabah I have often seen them in the company of
Graphium sarpedon visiting the
flowers of Bauhinia trees.
They also visit Mussaenda
bushes, and I have observed them nectaring at Lantana
in Perak, West Malaysia.
On Palawan and
Sumatra males apparently do not congregate, and are only rarely seen at
sulphur springs, preferring instead to obtain their sustenance
exclusively from the flowers of forest trees.
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Trogonoptera brookiana albescens,
male at hot sulphur spring, Kuala Woh |
Females are much
scarcer than males. My various visits to peninsular Malaysia and Borneo have enabled
me to see upwards of 1500 males in total, but only 2 females, one seen in
flight across a river at about 200 metres altitude, the other
flying high in trees near a waterfall at about 400 metres.
Some authors postulate that males outnumber females by
a ratio of as high as 200:1, but it is more likely that the sexes
occur in approximately equal numbers, but that the males due to
their habits are far more visible.
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Trogonoptera brookiana albescens,
wing detail |
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