Butterflies of
the Amazon and Andes
Demeter Longwing
Heliconius demeter
STAUDINGER,
1897
Family -
NYMPHALIDAE
subfamily -
HELICONIINAE
Tribe - HELICONIINI
Heliconius
demeter, Rio Shima, Satipo, Peru
Introduction
The tribe Heliconiini, colloquially known as Longwings, includes 71 species, all
confined exclusively to the neotropics.
The Heliconiini includes
the genera
Heliconius, Podotricha, Dryas, Agraulis, Dione, Dryadula, Eueides, Neruda, Laparus
and Philaethria.
The 39 Heliconius species are much
studied by geneticists and taxonomists. Many of them produce a
staggering variety of colour forms -
Heliconius erato e.g. produces no less than 29 geographical
forms, each of which corresponds almost exactly in colour and
pattern to a "sister" subspecies of
Heliconius melpomene flying in the same area.
All Heliconius species have elongated
black wings, marked with simple but striking patterns usually
featuring streaks or patches of red and cream, or blue and cream. A few,
such as
sara,
antiochus
and
wallacei have a metallic blue sheen over the basal area of both wings. All are
characterised by their delicate fluttering flight, long straight antennae, and
fondness for flowers.
Heliconius demeter is
found from Guyana to Peru and Bolivia. There are 15 described subspecies.
Habitats
This butterfly occurs commonly at elevations between about 200-1000m.
Lifecycle
The eggs are laid singly on the leaf buds of
Passiflora.
Adult behaviour
Heliconius butterflies are characterised by
having a very delicate fluttering flight, particularly when hovering
around flowers. They commonly nectar at
Hamelia, Lantana and
Palicourea.
Unlike other butterflies,
Heliconius females feed on pollen as well as
nectar.
Studies of ethilla have shown that
females deprived of pollen can only produce about 15% of the number of
eggs laid by females that have
access to it. This probably applies equally to other
Heliconius species including
melpomene. The pollen from
Psiguria,
Anguria and Gurania flowers provides amino
acids
that can't be obtained from nectar or other sources, and contributes
greatly to the longevity of the butterflies - some
Heliconius species are known to live for up to
9 months as adults.
Studies have shown that
Heliconius butterflies have home
ranges within which they can memorise the locations of nectar and
pollen sources, host plants and communal roosting sites. They are
able to plan the most efficient route by which to visit all nectar
/ pollen sources in the vicinity by using simple calculations akin
to what mathematicians call the "travelling salesman algorithm". Erlich & Gilbert demonstrated
that individual butterflies memorise the location of particular
Psiguria plants, which they visit daily, following a
predefined circuit through the forest.
In the genus Heliconius most species
rely entirely on airborne chemicals to locate mates. Males of
hecale,
ismenius and cydno are attracted by pheromones to the pupae of conspecific females.
The day before emergence a female pupa will usually have
several males in close attendance. A frantic battle
takes place the instant she hatches, as the males all struggle to copulate with her, not even
allowing her time to
expand and dry her wings. In some other
Heliconius species such as
hecalesia,
hewitsoni, erato,
charithonia and
sara the males don't even wait until the female emerges.
Instead they physically break open her pupa and copulate as soon
as her genitalia are accessible.
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