Butterflies of the
Family - LYCAENIDAE
subfamily - THECLINAE
Tribe - HYPOLYCAENINI
Assam, India ©
There are 45 Hypolycaena species, 22 of
which are found in the Afrotropical region, 1 in China, and 18 in
south-east Asia including 4 which occur in West Malaysia. In the
Australian region a further 4 are found, but they differ in several
ways from other Hypolycaena species.
Oriental Hypolycaena species are
commonly known as Tits.
The upperside of
the male of erylus is dark brown but
reflects a deep metallic purple sheen under certain lighting
conditions. It has a narrow black border, and on the forewings there
is a large black patch of androconial scales. The female lacks the
purple sheen, and has a series of broken white markings and black
tornal spots on the hindwings. The tails are present in both sexes.
Hypolycaena erylus is a common and
widespread species, found in India, Myanmar, Thailand, Laos,
Cambodia, peninsular Malaysia, Sumatra, Borneo, Sulawesi and Papua
Buxa, West Bengal, India
© Adrian Hoskins
This species occurs in many
habitats including coastal mangrove, lowland rainforest and
temperate hill forest, at elevations between sea level and about
Manas, Assam, India
© Adrian Hoskins
The eggs are laid
on Meyna pubescens,
Vangueria spinosa ( Rubiaceae ),
Cinnamomum zeylanicum ( Lauraceae ),
and probably on other plants.
After hatching and
eating their egg shells the tiny larvae are abducted by weaver ants
Oecophylla smaragdina. The same species
of ant also captures larvae of Anthene emolus.
The ants carry their captives into their nests, which are
constructed by weaving leaves together.
Oecophylla are large and extremely aggressive ants, but they
make no attempt to attack the larvae, which probably placate their
captors either by using a chemical deterrent, or by means of an
'appeasement song'. Research on various other Lycaenids has shown
that their larvae and pupae are able to stridulate, producing an
audible 'chirp' that can deter ants from attacking.
The larvae feed
within the ant nests on leaves, and possibly also on substances
regurgitated by the ants. Studies have demonstrated that 1st instar
larvae are unable to survive outside the ant nests and will not feed
on leaves outside the nest. This may be due to the warm and humid
microclimate within the ant nest, or it could be the case that a
substance produced by the ants softens the leaves and makes it
easier for the larvae to digest them. After the larvae moult to the
2nd instar, the ants then remove them from their nests, and
carefully transport them to young sprigs of the foodplant some
A few days later
when the larvae reach their 3rd instar they develop honey-producing
glands on their backs, and thereafter are constantly attended by the
ants, which "milk" them to drink the sugary secretion. The
relationship is not truly symbiotic, because while the larvae cannot
survive without the ants, the ants are able to obtain their 'honey'
from other sources.
The chrysalis is
smooth, plump, rounded and pale green in colour.
Males can commonly be found imbibing mineralised moisture from sand,
rocks, road surfaces or the walls of buildings in forested areas.
Both sexes nectar at various wild and cultivated flowers.
The adults always hold their wings
erect when feeding. They periodically oscillate their hindwings,
causing the little 'false antennae' tails to wiggle. This, in
combination with the 'false eye' marking at the edge of the wings,
gives the impression of a back-to-front butterfly, and diverts the
attention of predators away from the butterfly's head and body.
Birds generally try to predict which direction a butterfly will
take, so they aim their attack at a point just ahead of the
butterfly. Hypolycaena erylus and other
Theclinae turn this to their advantage, tricking the bird into
aiming behind the butterfly, which then flies forward and often
When not feeding, both sexes sit on foliage, often high up on bushes
or on the lower branches of trees, but they also sometimes settle on
low herbage and bask with their wings fully outspread.
© Adrian Hoskins