Butterflies of
the Amazon and Andes
Red Cracker
Hamadryas amphinome
LINNAEUS,
1767
Family - NYMPHALIDAE
subfamily -
BIBLIDINAE
Tribe - AGERONIINI
subtribe -
AGERONIINA
introduction
|
habitats |
lifecycle |
adult behaviour
Hamadryas amphinome, Yarinacocha,
Ucayali, Peru
Introduction
There are 20 members of the genus
Hamadryas,
commonly known as Crackers due to the ability of several species to
produce an audible signal that is similar to the crackling of bacon in a
frying pan.
The sound is made only by males, and is produced as they take flight to
intercept others of their own species. The crackling sound can be heard from
several metres away, and is made by twanging a
pair of spiny rods at the tip of the abdomen. Both sexes are capable of
detecting the sound - their wings have tiny hollow cells covered in membranes
which vibrate in response to sound waves, and stimulate nerve endings. The purpose of
the sound is unproven - it may be an alarm signal but from my observations it
appears to be a warning to other
males that stray into each other's territory.
All Hamadryas
species have a beautiful calico pattern on the upperside. In many there is a series of
submarginal ocelli on the hindwings, and distinct kidney-shaped stigmata in the
discal cells of fore and hind wings.
In several species such
as februa
and
glauconome
the ground colour is greyish and the pattern acts as an extremely effective
camouflage against the bark of trees. In other species such as
amphinome,
laodamia and
velutina
the wings are velvety black with a blue sheen and a pattern of bright blue
markings. The blue colour is produced by light diffracting as it reflects back
from microscopic prismatic ridges on the surface of the wing scales. The colour
varies slightly according to the quality, intensity and angle of the light, so
can appear as sky blue, cyan or even greenish in hue.
The common name Red Cracker refers to the colour of the underside hindwings.
Most
Hamadryas
species are found only in Central and South America, although 8 have been
recorded sporadically in the southern USA.
Hamadryas
amphinome
is distributed from Mexico to Peru.
Hamadryas amphinome, Yarinacocha,
Ucayali, Peru
Habitats
The Red Cracker is found in secondary or disturbed primary rainforest habitats at altitudes
between sea level and about 1200 metres. It also occurs in dry or humid
deciduous forests where it can often be abundant. In Guanacaste for example I
found several basking on mango trees in a small orchard in the rainy season (
July ), together with februa,
feronia and glauconome.
Hamadryas amphinome, Yarinacocha,
Ucayali, Peru
Lifecycle
The eggs are white, and
laid in chains of up to a dozen, hanging from the underside of leaves. The
caterpillars when fully grown are black, with yellow marbling along the back,
and have multi-branched spines that are black except for those on the middle
section which are orange. They feed gregariously on
Dalechampia scandens ( Euphorbiaceae ). The chrysalis strongly resembles
a small withered leaf. It varies in colour from green to dark brown, and has a
pair of flattened wavy head horns that are about half as long as the body. It is
suspended by the cremaster from leaves or stems.
Hamadryas amphinome, Rio Madre de
Dios, Peru
Adult behaviour
Like all
Hamadryas species
amphinome habitually basks on
tree trunks in a head-downward position and with the wings
flattened against the bark. They will bask in this position for
long periods to await potential mates. They commonly settle at a
height of about 2 metres but if disturbed by humans they fly up
and resettle higher up, either on the same tree or on another
nearby. They remain high in the trees until the intruder leaves,
and then descend the tree trunk in a series of short flights,
dropping a short distance each time until after several minutes
they resume their original position.
The butterflies
are active from sunrise to sunset, and are rarely seen away from
tree trunks. They feed mainly on decomposing fruit.
Hamadryas amphinome, Yarinacocha,
Ucayali, Peru
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