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Expert Insight
Issue 1, September 2001 by Simon Chan Kee Mun
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Common Name
Scientific Name
Family
Subfamily
Discovered by
Polymorphism |
: Lemon Emigrant
: Catopsilia pomona pomona
: Pieridae
: Coliadinae
: Fabricius in 1775 (the species and the form 'pomona')
: Yes. Two male forms and five female forms. |
One of the first few species to be encountered
by a beginner butterfly enthusiast, this is a fairly medium
sized to large robust insect. Generally abundant on the plains,
particularly so in secondary growth areas including public parks
and our own gardens, the males are easily identifiable, even in
flight, on account of their overall lemon colour. Identifying
females is harder though not impossible, due to their many
different colour forms. To complicate things further, there is
even one form of the female that looks like an
Orange Emigrant
in flight. Occasionally, individuals can be found flying in
forests and specimens have been taken before at altitudes up to
3,000 feet.
The genus Catopsilia, which is represented by two other species
here; ie Orange Emigrant and
Mottled Emigrant, can be
characterized by their energetic and rapid 'jumping' flight
maneuvers. Males of this genus can sometimes be found 'puddling'
or congregating at moist spots on roadsides or riverbanks to
imbibe precious
 minerals not found from nectar.
Known food plants or host plants include Cassia fistula, Cassia siamea and Butea frondosa. In Singapore, we have found its eggs,
caterpillars and pupae on the first two listed plants.
The life-history has been well documented and follows the usual Pieridae
fashion. Its eggs are spindle in shape and light yellow in colour,
usually laid singly on the surface of fresh leaves of the hostplant.
Its caterpillars are long , green and smooth with a massive round head.
All in all, the caterpillar will go through five phases or instars, from
totally green to darker green with a black and white lateral line. The
totally green pupa sans markings of any kind except a white line
along the abdomen area with a girdle is usually found stuck
under the leaf of the hostplant |
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Altogether there are two series of well-defined
forms in Singapore.
a) The 'crocale' forms - antennae black
above and underside of wings without silvery spots at the cell-ends. |
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Upperside creamy
white wings with base of wings lemon-yellow. Forewing apex
margined thinly with black - male, form
alcmeone
(Cramer 1777).
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Upperside creamy
white wings with costal margin of forewing and both termens
bordered with black. There is also black
submarginal markings, a black cell end spot on the forewing
and wing bases are tinged with yellow - female, form
jugurtha (Cramer 1777).
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Both wings have
broad black distal borders bearing a series of large,
diffuse, interneural whitish spots - female, form
crocale
(Cramer 1775).
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| b) The 'pomona' forms - antennae red above
and underside of wings with silvery spots outlined in red at
cell-ends. |
- Resembles male form alcmeone. However, the lemon-yellow
base is more restricted especially absent in the hindwing
tornal area - male, form hilaria (Stoll 1781).
- Pale yellow wings with black bordering and reduced
markings - female, form pomona (Fabricius 1775).
- Similar to form pomona but with white wings - female,
form nivescens (Fruhstorfer 1910).
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Red blotches on the underside - female, form
catilla (Cramer 1779).
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Written by : Simon Chan Kee Mun.
Photos by : Gan CW and Khew SK
Dated : 23rd August 2001.
Reference :
Butterflies of the Malay Peninsula by Corbet & Pendlebury 4th
Edition. |
