Butterflies of
the Amazon and Andes
Ocnus Ringlet
Magneuptychia ocnus
BUTLER, 1867
Family - NYMPHALIDAE
subfamily -
SATYRINAE
Tribe - SATYRINI
subtribe -
EUPTYCHIINA
Magneuptychia ocnus.
Rio Shima, Satipo, Peru
Introduction
There are 1100 known species of Satyrinae in the neotropical
region. About 400 of these are placed in the Euptychiina.
Butterflies within this tribe include the "ringlet" genera
Euptychia,
Magneuptychia,
Harjesia,
Cissia,
Caeruleuptychia,
Magneuptychia,
Harjesia etc; together with
Oressinoma and the various "wood nymph" genera i.e.
Parataygetis,
Posttaygetis and
Taygetis. Most are inhabitants
of the forest understorey and tend to fly close to the
ground. They generally avoid sunlight and prefer to fly at
dawn or on cloudy days when light levels and temperatures
are low.
Until
fairly recently almost all of the "ringlets" were placed in the
genus Euptychia,
but revisions by Forster and Lamas divide this convenience genus
into a number of smaller genera, on the basis of anatomical
differences and larval foodplants.
There are 40 known species in the genus
Magneuptychia including 11 recently described by
Lamas but as yet unnamed. The butterflies are slightly larger than most other
ringlets and typically have a grey ground colour overlaid with a bluish sheen.
The bands on the underside are always narrow, well defined and reddish in
colour. The ocelli on the hindwings are prominent and the 2 largest ones each
contain a pair of tiny white dots.
Magneuptychia ocnus
is distributed throughout the Amazonian region.
Habitats
The butterfly occurs in
tropical rainforest at elevations between 0-1500m.
Lifecycle
I have no data relating
to the lifecycle of ocnus. The lifecycle is likely
to be very similar to that of libye as follows:
The egg is round and
laid singly on or near the foodplants. The larva when fully grown is pale brown
with darker and paler lines and striations along the back and sides. The head
bears a pair of short conical horns. It feeds nocturnally on the grass
Panicum ( Poaceae ) and rests during daylight at
the base of the plant. The chrysalis is back with a hint of pink along the
abdomen.
Adult behaviour
The butterflies inhabit the understorey, and are usually only seen
along the darker and narrower trails.
They don't visit
flowers but feed instead at decomposing fungi
and bird droppings. Most of the time they sit
motionless on leaves in the shade, and if disturbed they generally fly a distance of no more than
3 or 4 metres, and then re-settle.
It is likely that the wings
reflect high levels of ultra-violet, enabling the butterflies to locate
potential mates visually in the dark environment where they breed.
The
vertical
lines on the underside are an example of disruptive colouration.
They help break up the outline of the wings into separate
shapes, making it more difficult for a bird to detect the
butterfly.
If however a bird
succeeds in discovering where it has settled, the butterfly has a
secondary defence in the form of the ocelli on the underside
hindwings. These function to divert attacks away from the
butterfly's vulnerable body, allowing it to escape with nothing worse than a
pecked
wing.
|
