Butterflies of
the Amazon and Andes
Padilla Glasswing
Oleria padilla HEWITSON, 1863
Family - NYMPHALIDAE
subfamily - DANAINAE
Tribe - ITHOMIINI
subtribe -
OLERIINI
Oleria padilla pseudomakrena, Rio Madre de Dios,
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
genus
Oleria
comprises of about 50 known species, characterised by the distinctive venation
of the hindwings.
Oleria
padilla is a common
and widespread species found from Ecuador to Bolivia. There are 6 known
subspecies, including the illustrated pseudomakrena
which occurs in the Andes of southern Peru and Bolivia.
Oleria padilla, subspecies
undetermined, Rio Kosnipata, Manu,,
Peru
Habitats
This subspecies occurs at altitudes between about 1200-1800m on the eastern
slopes of the Andes.
Lifecycle
I have no data
specific to padilla but the
following generalisations can be regarded as applicable to the genus
Oleria
:
The
eggs are white. They are laid singly although several may be dotted about on one
plant by any particular female.
The
larvae are dull greyish-green, with a wrinkled texture, and have
small shiny black heads. They feed on
Solanum
or Lycianthes
( Solanaceae ).
The
pupae are usually pale green, unmarked, and have compressed abdominal
segments and a dorsal hump.
Adult behaviour
Like other Ithomiines, the
butterflies spend long periods at rest on the foliage of small
shrubs in the darkness of their rainforest and cloudforest
habitats. They are extremely nervous, and if disturbed fly
immediately, only to resettle on another nearby leaf. The flight
is very slow, with characteristic deep wing beats. When feeding
in the open they behave very differently - both sexes being very placid and
reluctant to leave their flowers.
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.
In common with
most other Ithomiines, lateral and altitudinal migrations of
Oleria species are triggered by
seasonal changes in humidity.
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