Butterflies of the
Amazon and Andes
Family - NYMPHALIDAE
subfamily - DANAINAE
Tribe - ITHOMIINI
Pteronymia zerlina, female, Manu
cloudforest, 1700m, Peru ©
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.
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.
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.
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.
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 Pteronymia
contains 46 species, distributed variously from Mexico to Bolivia.
They are a diverse group with much variation in pattern and markings
between species, but can be recognised by the distinctive hindwing
venation. The butterfly illustrated here was kindly identified by
Ronald Brabant, an Ithomiine specialist.
is found throughout much of the Andes from Colombia to Bolivia.
Pteronymia zerlina, female, Manu
cloudforest, 1700m, Peru
This species inhabits cloudforest habitats at altitudes between
do not have data relating specifically to
but the following applies in general to butterflies in the genus
eggs are white. They are laid singly beneath the leaves of
Solanaceae. Females of most species return several times to the same
plant, laying up to a dozen eggs in total.
The larvae of Pteronymia
species vary in appearance, some being dark along the back, with a
pale central stripe, while others are banded in black and white, and
characterised by the presence of a pair of soft fleshy horns
projecting forward from the first thoracic segment.
pupae of this genus are typically squat in shape, with compressed
abdominal segments, and a bulbous thoracic section. They are
generally silver or gold in colour, shiny, and resemble large
raindrops hanging from stems or the undersides of leaves.
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 of most Pteronymia species
pollinate Epidendrum orchids.
sequester pyrrolizidine alkaloids from
Myosotis ( Boraginaceae ),
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.