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Butterflies of
the Amazon and Andes
Adina Clearwing
Dircenna adina
xanthophane HOPFFER,
1874
Family - NYMPHALIDAE
subfamily -
DANAINAE
Tribe - ITHOMIINI
subtribe - DIRCENNINA
Dircenna adina xanthophane, Rio
Pindayo,
Peru
Introduction
The Ithomiinae comprises of 376 known species, although it is
likely that at least another 30 will be discovered in the near
future. All are confined
to the neotropical region.
Ithomiines
are unpalatable to birds, and are consequently mimicked in
appearance by many other species. These include other unpalatable
species ( Müllerian mimics ), not only from the Ithomiinae but
also from several other butterfly families. There are also a large
number of edible species ( Batesian mimics ) which have evolved
similar patterns. Birds have the ability to memorise butterfly
patterns and so learn to avoid eating noxious species, but are
also fooled into ignoring similarly marked edible species.
Ithomiines are
characterised by having small eyes, slender abdomens and long
drooping antennae that lack distinct clubs. Males have a plume of
long androconial scales or "hair pencils" on the costa of their
hindwings. These are hidden from view when the butterflies are at
rest, but are displayed when the wings are held open during
courtship. Other Ithomiine characteristics include a very slow and
deep wing beat, and a preference for inhabiting the darkest
recesses of the forest understorey.
There are basically 2 types of Ithomiine. The first type are the
black and orange-banded "tigers", many of which are mimicked by
other species due to their unpalatability to birds. The second
type are the "glasswings", recognised by their transparent or
translucent wings, prominent veins, and orange wing margins. Many
genera contain examples of both of these types, and in some cases
an individual species may produce adults of both forms according
to location.
Most novices find the Ithomiinae very difficult to identify. Using
only the patterns to identify species is very unreliable because
there are so many similar species. Also many species produce a
variety of different colour forms according to locality and
season. The best approach therefore is to use the hindwing
venation and other anatomical features to identify the genus, and
to then look at the wing patterns to short-list the likely
species.
The 7 species in the genus
Dircenna all fall into the Glasswing category. They have
several features in common - all are fairly large in size, with
elongated forewings which have a very straight costa, and
distinctively shaped discal cells. The hyaline areas of the wings
in most species reflect a distinct greenish-yellow hue, although
in 2 species ( jemina and
olyras ) the wings are smoky orange.
Dircenna adina is distributed from
Colombia to Bolivia. There are 11 known subspecies, including
xanthophane which is restricted to
Peru.
Habitats
This is a rainforest species found at
altitudes between about 100-500m in the Amazonian lowlands and the foothills of
the eastern Andes.
Lifecycle
I have no data specific
to adina, and little is recorded about other member
of the genus. Dircenna relata
in Costa Rica lays its white eggs singly on Solanum ( Solanaceae ). It's larva
is described by DeVries as being short and squat, pale green-white and covered
with pale yellow warts.
Adult behaviour
The
butterfly is widespread and fairly common but nearly always
encountered singly. Both sexes nectar at Eupatorium flowers at dawn, and again in the late afternoon.
They also reportedly nectar at
Inga, Hamelia
and Impatiens.
Males sequester pyrrolizidine alkaloids from
Heliotropium, Tournefourtia,
Myosotis ( Boraginaceae ), Eupatorium,
Neomiranda
and Senecio ( Asteraceae ). These
chemicals confer toxic qualities to the butterflies which deter
bird attacks. The chemicals are also used in the production of
pheromones. Often the males of several
Ithomiine species will gather together at communal leks, where they release
these pheromones from hair-like androconial scales on the leading
edge of their upperside hindwings. These attract more males, which
in turn release
further pheromones. After a few days the lek may include 50 or
more adults comprised of as many as dozen
different species. Passing females are attracted to the
leks by the complex fragrances. Their presence stimulates the
males to open their wings and release further pheromones that
entice them into copulation. Females obtain sustenance from
nectar, and also visit bird droppings which provide them with a
source of nitrogen that assists with the development of their
eggs.
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