Thailand, Malaysia &
Family - LYCAENIDAE
subfamily - THECLINAE
Tribe - ARHOPALINI
female, Ulu Gerok, West Malaysia
© Adrian Hoskins
It is unclear how many species should be
classified within the genus Arhopala.
Some consider that the genus should only include a few Papuan
species and place all other related species in
Aurea. Here I follow the classification adopted by Corbet &
Pendlebury, who include all these genera within
Arhopala. Thus defined the genus is
widespread, with various species found from Afghanistan to Japan,
and south across the Pacific to Australia. In total there are over
220 species, collectively known as Oakblues.
The undersides of all species are earthy brown,
and bear a complicated pattern of dark spots and blotches, usually
edged in whitish.
Distinguishing the species is very difficult, and
best achieved by reference to the keys and genitalia illustrations
in Corbet & Pendlebury.
In Malaysia there
are at least 110 species, most of which are some shade of metallic
blue or purple on the upperside, although there are several
iridescent green species including aurea
Arhopala eumolphus is one of several
species which the males are metallic green above, but the females
are blue. It occurs from Myanmar to Java.
This species is one of the commoner Oakblues in
peninsular Malaysia, and occurs in primary forest habitats at
altitudes between sea level and about 600m.
The lifecycle has been studied, but the larval
foodplant has not been identified. Arhopala
species use a wide variety of foodplants including
Quercus ( Fagaceae ), and various
species of Myrtaceae, Combretaceae and Lythraceae.
The egg is laid singly on the underside of a
mature leaf, and is white, with a reticulated network of ridges.
Often several eggs can be found on one leaf, probably laid by the
same returning female.
The caterpillar hatches after about 2 or 3 days,
and partially eats its eggshell before moving away to find a fresh
young leaf, in which it nibbles tiny holes. When fully grown it is
oval in shape, slightly flattened, and pale translucent green in
colour with a prominent creamy dorsal line. It is attended by the
ant Polyrachis which milks it to obtain
sweet secretions exuded from it's dorsal honey gland.
The chrysalis is
formed on the underside of a leaf, and is pale brown, speckled with
dark olive dots.
Oakblues of both
sexes tend to spend most of their time sitting motionless on the
foliage of trees and bushes, at a height of about 2 - 5 metres. They
are not known to visit flowers, and males do not appear to come to
the ground to imbibe mineralised moisture. It seems likely that both
sexes obtain their sustenance from aphid secretions on leaves and