Butterflies of
the Amazon and Andes
Neotropical
Chequered Skipper
Pyrgus oileus
LINNAEUS, 1767
Family -
HESPERIIDAE
subfamily -
PYRGINAE
Tribe - PYRGINI
introduction
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habitats |
lifecycle |
adult behaviour
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Pyrgus
oileus, male, Tingo Maria, Peru |
Introduction
The
Hesperiidae are divided into 5
subfamilies - Grass Skippers ( Hesperiinae ), Spotted Skippers
( Heteropterinae ), neotropical Swifts (
Pyrrhopyginae ), Giant Skippers (
Megathyminae ), and the Flats or Spreadwing Skippers ( Pyrginae ).
The
Pyrginae are found throughout the world in all habitats. In the neotropical
region there are 990 described species, but this probably represents only about
80 percent of the true total. Unfortunately there are no illustrated reference
works which cover the entire fauna, so identifying many of them is extremely
difficult.
Pyrgus
oileus is probably
the most well known and easily recognised member of the genus Pyrgus,
which are known in Europe as Grizzled Skippers. In North America they are known
as Chequered Skippers, which can be confusing because the butterflies known in
Europe as Chequered Skippers belong to an entirely different subfamily - the
Heteropterinae.
All males in the genus Pyrgus
( and in several other Pyrginae genera ) have the basal half of the leading edge
of the forewing folded. Within the fold are hundreds of specialised wing scales
called androconia, from which pheromones are disseminated to entice females into
copulation.
There are a number of similar species, all of which have reduced and less
regular white spotting. Males of P.
oileus have a downy
covering of greyish-white scales which are not present in other neotropical Pyrgus
species. Females are darker, and lack the costal fold.
This
species occurs from the southern USA to Bolivia and Argentina.
Pyrgus
oileus, male, Tingo Maria, Peru
Habitats
Pyrgus oileus
can be found in a wide variety of disturbed semi-open habitats including
pastures, rainforest clearings, roadsides, grassland / forest mosaics and
farmland. It is commonest at altitudes between sea level and about 600m, but can
be found to at least 1800m, probably much higher.
Lifecycle
The eggs are cream in colour and laid singly on the upperside of leaves.
The
caterpillar is yellowish green with darker blotches, a thin line along the back,
and a black head. It feeds on the leaves of
Malvastrum
and Sida
( Malvaceae ).
The
pupa is greenish, or reddish-brown with a dark line along the back.
Pyrgus
oileus, male, Tingo Maria, Peru
Adult behaviour
Both sexes bask on low herbage,
bare ground or stones, with wings outspread. They have a rapid
darting flight, always close to the ground. The males are
territorial, using stones or small fallen branches as perches from
which they dart up to intercept females or to challenge other
males.
They visit a variety of low
growing flowering plants for nectar, feeding with the wings held
half open.
At dusk the
butterflies roost with their wings held erect, typically on dead flowers or
on the terminal leaves of herbaceous
plants growing in grassy forest clearings, along wide tracks
through secondary woodland, or along the edge of roadsides.
Pyrgus
oileus, male, Tingo Maria, Peru
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