Strange but true !
Odd postures !
There can be few butterflies or moths
as weird as this creature which I discovered in the rainforests of
While walking along a trail my attention was caught by what appeared
to be a dead leaf that seemed to have fallen and landed on a broad
green leaf. A spider appeared to be squatting in the middle of the
dead leaf, but somehow it all looked a bit too symmetrical.
Siculodes aurorula, Arima valley,
Closer examination revealed that the "dead leaf" was in fact the wings
of a moth, and the "spider" was it's body and legs. It
had adopted an extremely odd posture, with
it's body upright, and its legs and outstretched wings held in a
vertical plane. The wings are a marvellous example of camouflage -
perfectly disguised as a dead leaf, complete with windows to simulate
the nibblings of insects, and spotted with dark areas that could
easily be mistaken for leaf mould.
proved extremely difficult as there is hardly any published material
about neotropical moths available for reference. For many years I
was completely mystified by the insect, but it was finally
identified 10 years later by Mike Shaffer of the British Natural
History Museum, as
a member of the Thyrididae. My specimen was the first ever recorded
My photograph of the living moth finally revealed the purpose of its
incredibly long legs. These had long puzzled entomologists who had
studied the museum specimen. The moth needed them so that it could
prop itself up in this very odd upright posture. The pose is almost
threatening. Why would a moth evolve such a strange posture ?
Perhaps when viewed from the front it might appear so scary that it
would frighten off a small avian or reptilian predator ? Perhaps it
simply needs to raise itself clear of the substrate to avoid getting
stuck to it when the leaves are wet with rain ?
which look identical !
theory postulated by Henry Walter Bates states that by a process of
natural selection, many edible butterfly species have evolved wing
patterns which mimic those of distasteful species. The mimics
benefit because any bird which has suffered the unpleasant
experience of tasting an unpalatable species remembers the pattern
and is fooled into leaving the edible mimics alone.
By way of example, the
Heliconiine genus Eueides comprises of
12 medium sized butterflies which share almost identical anatomical
and morphological features, but which differ greatly in colouration
and patterning. Some, like isabella
appear to be mimics of orange / black banded Ithomiines, while
others including aliphera and
lineata are very similar to
Dryas iulia in appearance. Yet others,
such as vibilia, closely resemble
Eueides heliconioides falls into yet another group that
strongly resemble Laparus species. In
all these cases the "models" are considered to be distasteful to
avian predators, while all the "mimics" are believed to be edible.
This is called Batesian Mimicry.
Müller later theorised that unrelated and unpalatable butterflies
also mimic each other to increase each individual species' chance of
avoiding attack. Many orange / black banded species from the
subfamilies Danainae, Ithomiinae, Riodinidae, Nymphalinae,
Heliconiinae, Papilioninae, Pierinae, Dismorphiinae and Acraeini are
so similar that they are considered to be involved in a "mimicry
ring" known as the tiger complex, in which convergent evolution has
caused once dissimilar taxa to become almost identical. It is often
the case that males mimic one unpalatable species, while the females
mimic another entirely different one!
are a pair of
Müllerian mimics which were flying together in cloudforest habitat
at Shima in the Peruvian Andes.
Eresia eunice ( Nymphalinae ) ©
isabella dissoluta ( Heliconiinae ) ©
from humans !
Butterflies do some strange things to elude attention. The Zebra
Hairstreak Arawacus separata has a
pattern of stripes which creates the illusion that it is facing back
to front. It enhances the illusion by immediately turning to face
the opposite direction as soon as it lands on a leaf. There it
remains totally motionless until approached, at which point it
slowly but deliberately rotates to present the observer with a view
of it's posterior !
The pattern of striped directs
the eye towards the "false antennae" which are actually small tails on
the hindwings. It reinforces the illusion that it's tail is it's head,
by turning to face the opposite direction as soon as it lands on a
leaf. It even jiggles it's wings slightly to make the false antennae
move ! It's all part of a trick to divert bird attacks away from the
head, and allow the butterfly to escape. Clever eh ?
South American species, the Mosaic Colobura
dirce, spends long periods perching motionless on tree trunks.
It is normally a very tame insect, allowing humans to approach
closely, but if deliberately disturbed, instead of flying, it scuttles
around to the opposite side of the tree trunk to hide. If the observer
follows it, the butterfly runs back again, and repeated disturbance
causes it to literally run around in circles in a chase around the
tree trunk !
Strange feeding habits !
In temperate countries most adult butterflies feed
on flower nectar, although some will visit sap runs, or imbibe
dissolved mineral salts from dung, damp earth or carrion.
In the tropics many Nymphalids feed at rotting
fruit, while Swallowtails and Sulphurs prefer to drink from
urine-soaked ground, and many Hesperiine skippers are noted for
feeding at bird droppings. Rotting fish are a popular food source for
Agrias and certain other species in South
America, where I've also seen Ithomiine Glasswings feeding on the
corpses of flies.
In Malaysia, I've observed an
Allotinus species feeding directly from the honey glands of
aphids. In Ecuador I've watched the beautiful
Junea doraete gorging itself on the corpse of a snake, and
found the stunning metalmark Necyria bellona
feeding on the corpse of a toad.
Venezuela produced something even
more interesting - the gorgeous long-tailed metalmark known as the
Blue Doctor Rhetus periander, which was
seen feeding on the corpse of a giant tarantula.
Rhetus periander ©
One of the strangest habits however
is that of the brilliant orange Julia Dryas
iulia, which is quite content to feed at nectar in Costa
Rica, or to imbibe dissolved minerals from mud in Ecuador, but in
parts of Brazil groups of these butterflies are regularly seen
sipping the liquid in the corner of the eye of the yellow-throated