Butterflies of
Thailand, Malaysia &
Borneo
de Nicéville's Grass
Yellow
Eurema simulatrix
tecmessa
DE NICÉVILLE
Family - PIERIDAE
subfamily -
COLIADINAE
Tribe -
introduction
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habitats |
lifecycle |
adult behaviour
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Eurema
simulatrix tecmessa,
Taman Negara,
West Malaysia |
Introduction
The Grass
Yellows are all fairly small butterflies, readily recognised by
their bright yellow wings and their habit of gathering in small
groups on patches of damp sand or soil. Despite their name, none
of their caterpillars feed on grasses - the name is derived from
the fact that most species are found in disturbed grassy
habitats.
Grass Yellows are among
the most familiar of tropical butterflies, with a total of 70
known species worldwide, of which 36 are found in the Neotropical region,
13 in North America ( including Mexico ), 10 in Africa, 25 in
the Oriental region and 10 in Australia / Papua New Guinea. Many
of the species are migratory in
behaviour, with the ranges of several such as
hecabe overlapping into in 2 or more of the zoogeographical regions.
There are 9
species in peninsular Malaysia, most of which also occur in
neighbouring Thailand, and on Borneo and Sumatra. The commonest
member of the genus is hecabe, but
none except senna are rare,
although ada,
andersonii, brigitta and
tilaha tend to be localised in
distribution.
Eurema simulatrix is found in
Sikkim, Myanmar, Thailand, Laos, West Malaysia, Singapore,
Palawan & Mindanao ( Philippines ), Sumatra, Sabah, Brunei,
Sarawak, Kalimantan, Sulawesi, Java and on many of the smaller
islands in the region.
Habitats
This species is found in secondary or disturbed habitats
including forest clearings, along roadsides and riverbanks, and
in parks and gardens at elevations between sea level and about
900 metres.
Lifecycle
The lifecycle appears to be unrecorded, but it is possible to
make educated guesses :
The eggs of
Eurema species are always
spindle-shaped, and pale yellow or straw coloured when first
laid, changing to a darker shade before hatching. They are laid
singly on the upperside of leaves of the foodplants.
The foodplants
of simulatrix are not recorded.
Other Oriental Eurema species are
known to feed on Caesalpinia,
Cassia, ( Caesalpiniaceae ),
Pithecellobium ( Mimosaceae ) and
Wagatea ( Fabaceae ).
The
caterpillars of Eurema species when
first hatched are typically green, cylindrical, and covered in
tiny tubercules from each of which arises a single long stiff
hair. In later instars the hairs ( setae ) become progressively
shorter. The fully grown larva in most
Eurema species is dull green with a thin dark dorsal
stripe, and a broader cream lateral stripe below the spiracles.
Each segment of the body is ribbed vertically, and covered in
small tubercules, giving it a rough textured appearance.
The chrysalis
will be shaped similarly to that of other members of the
Coliadinae - slim, sharply pointed at head and tail, and with
prominent wing cases. It is likely to be pale green or straw
coloured, and probably marked with fine blackish speckling.
Adult behaviour
Males
congregate to imbibe mineralised moisture
from damp sandbanks, usually in groups of less than a dozen,
unlike hecabe which gathers in
scores. E. simulatrix also tends to
be found in mixed aggregations which often include other
Pierines such as Appias,
Papilionids such as Pathysa and
Graphium, and Nymphalids such as
Vindula.
Females are
more discreet in behaviour, normally being seen singly when
nectaring. They will visit many different flowers, but generally
seem to prefer smaller less conspicuous species.
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