Butterflies of
the Amazon and Andes
Thoasa Sister
Adelpha thoasa
HEWITSON, 1850
Family - NYMPHALIDAE
subfamily -
LIMENITIDINAE
Tribe - LIMENITIDINI
Adelpha thoasa, Satipo, Peru
Introduction
Adelpha
butterflies are colloquially known as "Sisters". In terms of
appearance they are reminiscent of the White Admirals (
Limenitis
) of Eurasia, and share with them a fondness for flitting gracefully around the
lower branches of trees in the dappled sunlight of the forest.
There are 85 known species of
Adelpha,
all except one of which are confined to Central and South America. They are
characterised by the distinctive black marbled pattern overlaid on a dark brown ground colour; and by
having a broad orange or white band on the
forewings. In the vast majority of species this band also extends vertically
down to the tornus of the hindwings.
While it is easy to recognise the genus, determining the individual
species
can sometimes be very difficult - a problem exacerbated by misidentified
museum specimens and mislabelled illustrations in many entomological books. The only reliable
identification resource
is "The genus Adelpha" by Keith Willmott.
Accurate identification requires
meticulous examination of the configuration of the orange markings in the subapical area
on the forewing, and of the precise shape of the vertical bands. It is also essential
in most cases to examine the patterning on the underside.
Adelpha
thoasa is found in Ecuador, Peru, Bolivia and south-west Brazil.
Adelpha thoasa, Ecuador
© Tony Hoare
Habitats
This species occurs in lowland and pre-montane rainforest at altitudes
between about 200-1000m.
Lifecycle
I have no data specific to
thoasa. The following generalisations apply to the
genus Adelpha:
The
eggs of most
species are white or pale green, and are laid singly on leaves of the foodplants
which include
Rubiaceae, Moraceae, Urticaceae, Verbenaceae, Melastomaceae, Bombacaceae,
Ulmaceae, Piperaceae, Tiliaceae or Ericaceae according to species.
The
young larvae nibble away at the tips of leaves, leaving the midrib projecting.
They construct a chain of frass along the midrib and rest at the end of it. The
frass chains appear to act as a deterrent to ants, spiders and parasitoids which
find it difficult to walk on them. When fully grown the larvae are cryptically coloured
and resemble bird droppings, mossy twigs or bits of curled up dead leaf. They
have 2 rows of conspicuous spines along
their backs, those on the first two segments being enlarged and directed forward,
while the third pair are directed backward. The
pupae, which are suspended by the cremaster, are in some species green or brown,
while others are entirely silver, and shiny. The pupae of some species are
decorated with numerous spikes and projections, and sometimes have very
prominent palpi.
Adult behaviour
Adelpha thoasa
is usually encountered as solitary males, seen when imbibing
moisture from boulders, logs, tree trunks or damp soil. The
butterflies usually keep the wings outspread while feeding.
|
