Butterflies of
Africa
Eresine Harlequin
Mimeresia semirufa
GROSE-SMITH, 1902
Family - LYCAENIDAE
subfamily -
LIPTENINAE
Tribe - MIMACRAEINI
Mimeresia semirufa,
Bunso, Ghana
Introduction
The
subfamily Lipteninae is wholly African in distribution, and comprises of no less
than 600 species, varying from the tiny
Eresiomera bicolor to the dazzling bright metallic blue
Epitola posthumus - a species which with a wingspan
of 65mm is massive by Lycaenidae standards.
The Lipteninae are fascinating
because of their association with "ant trees", i.e. trees which support colonies
of Crematogaster ants. As with most other
Lycaenidae species, the caterpillars of Liptenids have ants in almost constant
attendance. The ants "milk" a sugary substance from a gland on the caterpillar's
back, and in return for this reward the caterpillar benefits because the
presence of the aggressive ants deters other insects such as wasps and flies
that would otherwise attack them.
Mimeresia comprises of
about 15 species. The genus is unusual in that the genitalia of the males are
identical in all species ( within most butterfly genera the genitalia differ
greatly, and are used by taxonomists as species indicators ). The individual
species however differ strongly in colour and pattern, and their status as full
species is confirmed by DNA analysis.
The male of
semirufa is very similar on the upperside to
Eresiomera bicolor, being black, except for the
upper half of the hindwing, which is bright orange-red. The female is a dirty
yellowish colour, with broad blackish borders, and a black apex and costa. The
under surface of the wings is heavily dusted with ochreous scales in both sexes.
Mimeresia
semirufa is found only in Cote d'Ivoire and Ghana.
Habitats
This is a scarce and localised species, found in relatively undisturbed forests,
at altitudes between about 100-400m.
Lifecycle
The caterpillars feed on blue-green algae
growing on the bark of trees that have been colonised by
Crematogaster ants, with which they are assumed to have a symbiotic
relationship. The ants milk the larvae to obtain sugary secretions from a gland
on their backs. In return, the presence of the ants is beneficial to the
butterflies, providing them with a degree of protection from parasitoid wasps
and from small predatory insects. The caterpillars of many Lycaenidae produce a
"song" to appease their normally aggressive ant hosts, by stridulating chitinous
areas of their bodies. It is likely that further studies will also reveal this
to be the case with Liptenids.
Adult behaviour
The butterflies are rarely encountered during the daytime, when
they probably spend most of their time flying around the upper
branches of the "ant-trees", or feeding at extrafloral nectaries.
In late afternoon they go to roost hanging from thin dry twigs,
usually about 2 metres above ground level.
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