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Butterflies of
the Amazon and Andes
Gaudy Sister
Adelpha boreas
BUTLER, 1866
Family - NYMPHALIDAE
subfamily -
LIMENITIDINAE
Tribe - LIMENITIDINI
Adelpha boreas, male, Manu
cloudforest, 900m, Madre de Dios, 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
boreas can be
confused with several other species including
saundersii, ximena, irmina
and salus.
These species are distinguished from one another by close examination of the
pattern formed by the orange band on the forewings, and by differences in the
underside markings.
Adelpha
boreas is a
widespread species found from Costa Rica to Bolivia.
Habitats
This species occurs in primary and disturbed rainforest and cloudforest habitats at altitudes
between about 200-1200m.
Lifecycle
The
egg is white,
and is laid singly on leaves of Satyria
( Ericaceae ).
The
young larva nibbles away at the tip of a leaf, leaving the midrib projecting.
It constructs a chain of frass along the midrib and rests at the end of it.
Frass chains appear to act as a deterrent to ants, spiders and parasitoids who it difficult to walk on them.
The fully grown larva is disguised as a mossy twig, being mottled
green and brown, and covered with small whorled spines.
Adult behaviour
This species is usually encountered as solitary males, seen flitting
and gliding in sunny areas in the vicinity of waterfalls and
streams. The butterflies periodically alight to imbibe moisture
from damp ground, and usually feed with wings outspread or half
open.
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