Butterflies of
the Amazon and Andes
Hewitson's Olivewing
Nessaea hewitsoni
FELDER & FELDER, 1859
Family - NYMPHALIDAE
subfamily -
BIBLIDINAE
Tribe - EPICALIINI
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Nessaea
hewitsoni,
Madre de Dios, Peru |
Introduction
There
are 4 known members of the genus
Nessaea,
namely
aglaura,
batesii,
hewitsonii
and
obrinus,
all of which are confined to the neotropical region.
All of the species have similar undersides. The uppersides of
Nessaea males are very dark brown, with bright sky blue diagonal bands on the forewings. The male of hewitsonii
also has blue markings on the hindwings, but the remaining species including batesii
have orange patches on the hindwings instead. The females of all species
have plain brown hindwings, blue diagonal bands across the forewings, and
elongated reddish spots within the discal cell of the forewings.
Nessaea hewitsoni
is found throughout eastern Andes from Colombia and Venezuela to Bolivia, and
across the western Amazonas of Brazil.
Nessaea
hewitsoni,
Catarata Bayoz, La Merced, Peru
Habitats
Nessaea are usually seen singly, and breed in
wet primary
rainforest at altitudes between 0-800m. They are not usually
encountered in secondary forest, and it is very unusual for them to be seen in
open sunny areas, although I have observed males of
Nessaea aglaura
in forest edge habitats and degraded forest in Ecuador.
Lifecycle
The yellowish-green barrel-shaped eggs are laid singly on leaves of seedling
Alchornea,
Plukenetia and other trees in the family
Euphorbiaceae.
The
larva when fully grown is jade green. Each body segment adorned with enormous
whorled spikes which are amber in colour. The head is bluish and armed with a
pair of long head horns. The larva adopts the usual Biblidini resting posture
with it's body arched and it's face appressed to the substrate so that the
spines are directed upward. If it is molested the larva twitches
violently, swinging it's head from side to side. The
pupa is dark green, and is attached by the cremaster from the upperside of
a leaf, projecting horizontally.
Adult behaviour
The butterflies are usually found as singletons, but it is not
unusual
to see several males and one or two females during an hour long
walk along a narrow forest track in suitable habitat.
All
Nessaea species are fast flyers. When
at rest they are very alert to movement. If alarmed they
fly off very rapidly and with great agility. They usually resettle a short
distance away but invariably return to the original spot within a
few minutes. Normally they settle on foliage about 1-3m above the
ground, and close their wings immediately upon
landing. They then wait motionless for a few minutes, and if
undisturbed they will slowly open their wings to bask.
Males feed at
fallen fruit, and can be baited with plantain. They are also
attracted to mammal dung and urine on forest tracks, but unlike
many other members of the Biblidini they are not attracted to
sunny river beaches or other open areas.
Nessaea
hewitsoni,
Catarata Bayoz, La Merced, Peru
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