Butterflies of the
Amazon and Andes
Family - NYMPHALIDAE
subfamily - DANAINAE
Tribe - ITHOMIINI
Tithorea tarricina parola, Medellin,
The Ithomiini 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 Ithomiini 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.
Tithorea are large butterflies. They
often fly in sunny glades where they can easily be confused with
Heliconius species such as
or hecale. The easiest way to
distinguish Tithorea from their mimics
is to examine the antennae and legs. Tithorea
antennae are very gradually tapered, and drooping. In Pieridae they
are parallel along the stalk, with a strongly clubbed tip, while in
Papilionidae the tip is clubbed and recurved. Ithomiines,
Heliconiines and Nymphalines have only 2 pairs of functioning legs.
In the Ithomiines these are long, giving the impression of a
butterfly on stilts. Papilionidae and Pieridae have 3 pairs of
Tithorea tarricina is one of the
commonest and most widespread species, being found from Mexico to
Bolivia. There are 9 named subspecies.
This species inhabits rainforest and cloudforest at elevations
between about 200-2000m.
The larvae feed on Apocynaceae. These plants contain toxins that are
ingested by the larvae and passed on to the adult butterflies,
rendering them highly distasteful to birds. The larva of
tarricina is green with a dark band
around each segment, and has two long filaments arising from the
first thoracic segment. The pupa is silvery and resembles a large
Tithorea tarricina is usually encountered
singly. In sunny weather the adults are secretive, flying in light
gaps in the understorey. In overcast conditions however they emerge
into more open areas along the edges of streams or wide forest tracks.
They often settle on low foliage, slowly fanning their wings.
Males are attracted to bird droppings, from which they obtain
pyrrolizidine alkaloids. The chemicals serve multiple purposes - they
increase the toxicity of the butterfly rendering it unpalatable to
birds, they are essential in the production of pheromones, and they
are transferred to the female during copulation thereby increasing her
longevity and fertility. Males often visit the same bird dropping on 3
or 4 successive days.