Butterflies of
the Amazon and Andes
Puna Clouded Yellow
Colias euxanthe
FELDER & FELDER, 1865
Family -
PIERIDAE
subfamily -
COLIADINAE
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Colias
euxanthe hermina, male, Shismay,
Peru. |
Introduction
Butterflies in the subfamily
Coliadinae, commonly known as Brimstones, Sulphurs, Grass Yellows and Clouded
Yellows, are found in all parts of the world, and total about 300 species. The
majority are migratory in behaviour -
Colias crocea for
example migrates each summer from north Africa to England, and
Phoebis agarithe
migrates seasonally from the Amazon lowlands to moderate altitudes in the Andes.
Colias
euxanthe is one of
several Clouded Yellow species which breed at high altitudes in the Andes, and
is also migratory in behaviour, crossing seasonally from north to south along
the Andean range, and also from the Pacific slope to the eastern Andes.
The butterfly occurs in Ecuador, Peru and Bolivia.
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Colias euxanthe hermina, female, Shismay, Peru. |
Habitats
This species breeds on dry puna grasslands and lightly grazed pastures at elevations
between 2800-4000 metres, in areas bathed in the warm sunshine above the cloud
line for most of the year.
Lifecycle
The lifecycle appears to
be unrecorded, but the following characteristics are typical of the genus Colias,
and therefore probably applicable to euxanthe
:
The
eggs are bottle-shaped, ribbed vertically, in most species are creamy yellow or
pale green when first laid, but later turn orange or dark crimson. They are
nearly always laid singly, on the leaves of the larval foodplants.
The
caterpillars are typically green, with a white or yellow lateral line that is
sometimes edged with by a series or black or pinkish dashes. The spiracles are
usually highlighted in yellow or orange.
The
larval foodplants of Colias
species are varied, North American Colias species
for example feed on plants including Leguminous herbs such
as Lotus, Vicia, Trifolium
and Astragalus,
and on dwarf sallows Salix,
and bilberry Vaccinium.
The pabula used by most neotropical species are unknown.
The
chrysalis is usually green or straw coloured, and fixed vertically to a stem by
the cremaster and a silken girdle.
Adult behaviour
Migrating adults fly rapidly
across the Andean grasslands, stopping momentarily to nectar at any
available flowers, and often patrolling back and forth along
ridges.
At an altitude of about 3500m,
on a plateau on the eastern Andes of southern Peru, I found what
appeared to be a breeding site. At least 15 adults were flying in
a small cultivated area of irrigated grassland. The crop was an
unidentified grass, amongst which were growing various wild
flowers. The butterflies periodically took to flight, always
keeping low to the ground, flying rapidly from flower to flower,
nectaring at gentians ( Gentianaceae ).
At another site, on steep Andean
mountainsides in central Peru, I found a very isolated colony,
with 6-8 adults on the wing, in a small field, lightly grazed by
horses. Here, euxanthe shared it's
habitat with it's larger and brighter relative
Colias lesbia.
Colias
euxanthe hermina, male, Shismay,
Peru.
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