Butterflies of
the Amazon and Andes
Harmonia Tiger
Tithorea harmonia
CRAMER, 1777
Family - NYMPHALIDAE
subfamily -
DANAINAE
Tribe - ITHOMIINI
subtribe -
TITHOREINI
introduction
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habitats |
lifecycle |
adult behaviour
Tithorea
harmonia hermias, Satipo, Peru
Introduction
The tribe
Ithomiini contains 372 known species, all of which are confined
to the neotropics. They
can be divided rather unscientifically into 2 groups - the
Tigers and the Glasswings, although both types are represented in
some genera.
The Tigers are regarded as part of a
huge "tiger complex" in which many toxic species from the
Ithomiini and Danaini share a basically similar pattern of black
wings, strongly marked with bands or stripes of bright orange. The
Müllerian mimicry theory, in simple terms, states that by
sharing a common pattern, toxic species are less likely to be
attacked by predators, who having experienced one distasteful
insect will avoid eating others with similar colours and markings.
The matter is made more complicated
because many other non-toxic species, including members of the
Pieridae, Papilionidae, Heliconiinae and Riodinidae have similar
patterns. The theory of Batesian mimicry states that these
have evolved to look similar to the toxic species so that
predators will avoid them also.
Although widely accepted, such
theories are flawed. A species which is avoided by one species of
bird will be readily eaten by another species that has greater
tolerance of the toxins. The degree of toxicity varies from one
butterfly species to another, and from one individual to another,
so a predator could feasibly eat many such insects without ill
effect. Furthermore it must be borne in mind that all butterflies
and moths, of whatever family, according to evolutionary theory
must share a common ancestor, and therefore a common
pattern-creating mechanism, so the fact that so many look similar
is possibly more a matter of coincidence than "mimicry".
The easiest way to distinguish this
species from it's "mimics" is to examine the antennae and legs.
The antennae of
Tithorea
are very gradually tapered, cream in colour, and drooping. In
Pieridae the antennae 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 functioning legs.
Tithorea
harmonia is one of
the commonest and most widespread of the toxic "tiger" species, being
found from
Mexico to the southern Amazon. There are 26 named subspecies.
Habitats
This species is found in sub-tropical deciduous forest as well as in evergreen
rainforest habitats. It occurs from sea level to an altitude of about 1300m.
Lifecycle
The larvae
feed on Prestonia acutifolia ( Apocynaceae ). These
foodplants are highly toxic to
birds and other small vertebrates, the chemicals within them
are accumulated by the larvae, and
passed on to the adult butterflies, rendering them
highly distasteful to birds. In almost all other Ithomiine species however the
toxic pyrrolizidine alkaloids found in the adult butterflies are sequestered by
the adults from flower nectar and / or plant exudates.
I do not have any descriptions of the early
stages of harmonia, but they are likely to be similar to those of the closely related species
T. tarricina. The larva of the latter is pale green with dark bands around the segments, and has two long
filaments arising from the first thoracic segment. The pupa of
tarricina
is silvery and resembles a large water droplet.
Tithorea
harmonia hermias, Madre de
Dios, Peru
Adult behaviour
Tithorea harmonia is usually
found in two's and three's, but at some sites in Peru I have found
as many as 20 flying together.
In sunny weather the
butterflies tend to be secretive, flying in light gaps deep within
the forest. In cloudy conditions, and at the approach of dusk,
they emerge into more open areas along the edges of streams, or
wide forest tracks. There they can be seen fluttering amongst
herbage, or settled on low foliage, slowly fanning their wings.
At the end of the dry season
they tend to gather at the last remaining sources of moisture
within the forest - dry river beds, muddy pools etc, but tend to
avoid open riverbanks and forest roads.
Males are strongly attracted to
bird droppings, from which they sequester pyrrolizidine alkaloids.
These chemicals seem to serve multiple purposes -
they may be essential in the production of pheromones, they may
increase the toxicity of the butterfly, and they are probably
transferred to the female during copulation, implying that males
with high concentrations are essential for the production of
fertile and viable eggs by the female. The males will often visit
the same bird dropping for 3 or 4 days in succession.
Females are more
often seen visiting flowers, including
Psychotria, Hamelia
and Chomelia species. They
share the Heliconiine habits of spending quite long periods
nectaring at any particular bloom, and habitually return to the
same flower over a period of days. Normally when feeding they keep
their wings closed, but sometimes fan them slowly.
In dry weather
the butterflies roost openly on foliage in the understorey, but
during rainy spells they hide amongst the rootlets of palms.
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