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Strange, but true !
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Weirdest caterpillar on Earth ?
Caterpillars come in some strange
shapes, but there can be few creatures more weird-looking than this moth
caterpillar ( family Limacodidae ) from French Guiana. Note that this photo does
not depict a group of caterpillars - it is a single caterpillar which has
enormous hairy limb-like lateral extensions to each segment !
Click
here
for more amazing caterpillars !
Plants that trick
butterflies !
Caterpillars of Cattle
Heart butterflies (
Parides
) from South America feed on
Aristolochia
vines, but some vines can defend themselves by only "permitting" the butterflies
to lay a small number of eggs. If extra eggs are laid, the leaf around the egg
dies, and the dead tissue drops to the ground, carrying the egg with it !
A
similar trick is played by
Passiflora vines,
which produce stipules ( small false leaves ) at the base of leaf stems, that induce egg laying
by some species of Heliconiine
butterflies. A day or two later the stipules drop off, carrying the eggs with
them. Some other Passiflora
vines produce tiny tubercles on the stipules that mimic Heliconiine
eggs. Any butterfly visiting the plant sees the false eggs and is misled into
thinking that the plant is already overladen with eggs, so is
inhibited from adding more.
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Heliconius
erato luscombei, Rio Madre de Dios, Peru |
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Wings that can hear !
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Some butterflies
can detect sound, using "ears" on the underside of their wings.
These microscopic funnel-shaped ears are covered with a very thin
membrane that vibrates in response to high frequency sound. The
ear is only present in certain butterfly families.
Some scientists
believe that all early butterflies were nocturnal, and that
the ears evolved to enable them to detect and avoid predatory bats.
Other butterfly families which do not possess ears are thought to
have evolved daytime flight as an alternative anti-bat strategy. |
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Killer caterpillars !
Caterpillars of the Scarce
Swallowtail Iphiclides
podalirius are
territorial. The silk trails which they lay as they walk along twigs have a
slight odour. This enables each larva to recognise it's own silk trail, and use it as a route map to
find it's way back to particularly succulent leaves. If two larvae meet, the
larger one spins a silk web around the smaller one to kill it, or bites it to
death.
Epiphile
caterpillars in South America are equipped with long sharp poisonous "antlers"
which they use to defend themselves against other insects. If disturbed they
swish their heads violently, using the antlers to puncture the skin of attacking insects. The
lepidopterist A. Muyshondt observed
Epiphile
caterpillars attacking each other, locking antlers until death.
Run and jump in Ghana !
In 2001, at Boabeng-Fiema
rainforest in Ghana, I observed the strange antics of a leaping caterpillar.
Crawling towards the tip of a leaf, it came to a "dead end", whereupon it
rapidly shuffled backwards a couple of inches, before taking a run and jump to
leap across to another leaf about 9 inches away. Fascinated by this
extraordinary behaviour I continued to watch as the larva repeated the process
several times to migrate across the bush.
Intelligent butterflies !
The seemingly complex courtship
rituals of many butterflies implies that they have some degree of intelligence,
but careful analysis shows that the rituals are merely a series of instinctive
responses to specific stimuli. A female for example might settle and open her
wings if showered with pheromones, but the male then has to respond in a
particular way which signals the female to initiate the next stage in the
ritual, and so on.
There is some evidence however
that certain butterflies do demonstrate intelligence. The Heliconius
butterflies of South America live for several months, but never stray beyond
their local patch of forest, although other perfectly suitable habitats may be
nearby. The reason is because they learn the precise locations of scarce Psiguria
plants in their home range, and systematically visit them each day to gather
pollen, which provides them with amino acids that are essential for egg
production and longevity.
The butterflies live solitarily,
but roost communally, and are able to learn the locations of regular roosting
sites. They are thought to roost together as a defensive strategy - when a bird
eats one Heliconius
butterfly and finds that it tastes bad, it is likely to leave the other
butterflies alone.
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