Butterflies of
the Amazon and Andes
Hewitson's Mimic
Eresia datis
HEWITSON, 1864
Family - NYMPHALIDAE
subfamily -
NYMPHALINAE
Tribe - MELITAEINI
subtribe -
PHYCIODINA
Eresia datis phaedema,
Satipo, Peru
Introduction
The tribe Melitaeini is of worldwide distribution. It includes the
Crescents and Checkerspots of North America, and also many familiar European
species such as the Marsh, Spotted and Heath
Fritillaries.
Eresia
are closely related to
Castalia, Anthanassa and
Janatella, in fact that
these genera can only be distinguished by microscopic examination
of the male genitalia.
The 20 Eresia
species fall into 2 distinct
groups. Some e.g. nauplius
are black with bands or patches of white. Most however are strongly
marked in black and orange, and regarded as Batesian mimics of toxic
Ithomiinae.
Eresia datis is particularly
interesting as it's various races appear to be Batesian or
Mullerian mimics of different Heliconiini and Acraeini species. The similarity between
the upperside wing patterns of
Eretis datis phaedema and the Acraeine species
Actinote anteas are too strong to be
coincidental; as is the similarity between the southern race Eresia datis
corybassa and certain forms of Heliconius melpomene
and H.
erato.
Eresia
datis is
distributed from Colombia to Bolivia. Subspecies corybassa is found in
southern Peru and Bolivia, while subspecies
phaedema is found in central / northern Peru and Ecuador.
Eresia datis phaedema,
Satipo, Peru
Habitats
This
is a sun-loving species found in cloudforests at altitudes between
about 1400-2800m. It tends to fly in forest edge habitats, e.g. along
roadsides and riverbanks.
Lifecycle
I have no
information specific to datis but the lifecycle is
probably similar to that of
ithomioides,
in which the pear-shaped eggs are cream coloured, and laid in batches of up to
70 beneath leaves of Pilea ( Urticaceae ).
At least one other Eresia species -
coena, oviposits on Justicia
( Acanthaceae ). The larva of ithomioides is dark
green with orange spikes and white dots along the back. The head and legs are
orange. Its pupa is olive-brown, shiny, and suspended by the cremaster
from stems.
Adult behaviour
The butterflies have a slow fluttery flight. They are usually
only encountered in sunny conditions, and can be seen as
singletons flying along roadsides or other forest-edge habitats.
Males are often seen imbibing mineralised moisture from damp sand
or rocks. They usually keep their wings closed when feeding, but
sometimes bask on the ground or on low vegetation, with wings fully
outspread, when clouds temporarily obscure the sun.
Eresia datis corybassa,
Manu cloudforest, 1900m, Peru
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