Butterflies of
the Amazon and Andes
Juturna Underleaf
Eurybia juturna
FELDER & FELDER, 1865
Family - RIODINIDAE
subfamily -
RIODININAE
Tribe - EURYBIINI
Eurybia juturna, Tingo Maria, Peru
© Peter Bruce-Jones
Introduction
There are about 20
Eurybia
Underleaf butterflies, which occur variously throughout the neotropics from
Nicaragua and Honduras to southern Peru and Bolivia.
All have greyish or brownish uppersides with a series of
squarish submarginal markings. Several species e.g.
molochina
and
lycisca
have a blue iridescence across the upperside hindwings.
Almost all species have a prominent orange-ringed false eyespot in the discal cell of each forewing. Only
halimede, albiseriata, elvina
and the falcate-winged
carolina
and
pergaea lack these eyespots, and hence are commonly known as "blind" underleafs.
In
all species the
upperside pattern is repeated on the under surface, but the under surface is
paler, and the markings less conspicuous.
Other
Eurybia characteristics include
metallic green eyes and an extremely long proboscis that is almost
twice the length of the body, enabling the butterflies to reach
deep into flowers for nectar.
Eurybia
juturna is known from Colombia, Ecuador,
Peru and Bolivia.
Habitats
This species occurs in primary rainforest at elevations
between sea level and about 1000m. It is never seen in open sunlit areas,
instead preferring the darkness of the forest understorey.
Lifecycle
I have no data regarding
juturna but the lifecycle is likely to be
very similar to that of other Eurybia species as
follows: The eggs are like flattened lozenges and are laid singly on the stems
and leaves of Calathea,
Ichnosiphon, Maranta,
( Marantaceae ), Costus and
Renealmia ( Zingiberaceae ). The larvae are maggot-like, and feed on the flowers,
not the foliage. Older larvae can be found in ant nests within sheaths
surrounding the stems of the foodplants. They are constantly
attended by ants which milk them for a sugary substance secreted
from a dorsal gland. The larvae are parasitised by
Rogas and other Braconid wasps.
The proboscis on the
butterflies is very long, and there is a correspondingly
long-proboscis casing on the pupa, which extends about 2cms beyond
the tip of the abdomen.
Adult behaviour
The butterflies are very secretive by nature, spending very long
periods resting under the leaves of low growing vegetation, always
with wings spread open, cheekily peering
out to play peek-a-boo with only their eyes and antennae visible
to observant passers by.
They are extremely wary and have excellent eyesight. They can
detect the tiniest movement, and instantly dash out at high
speed to investigate any passing butterfly, then almost
instantaneously return to resettle under the same leaf, or one
very nearby. The degree of agility apparent when they
fly into the vegetation, flip upside-down and settle under a leaf
is quite amazing to behold.
I
have never observed any form of prenuptial ritual in
Eurybia species, and assume that
courtship is extremely swift and leads to almost instant
copulation. I have on occasions found copulated pairs of
Eurybia at rest beneath low
foliage with wings outspread.
All
Eurybia species have an extremely
long proboscis which enables them to
probe for nectar into the deep flowers of
Heliconia plants. The easiest way to observe the
butterfly is to find an isolated
Heliconia growing in the forest, and to wait
nearby until one arrives.
DeVries records that large numbers of
Eurybia adults are eaten by Anolis
and Norops lizards.
|
