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Caterpillar– The Eating Machine
Theivaprakasham Hari
theivaprakasham@gmail.com
Butterflies are very special and fascinating creatures that totally transform themselves from miniature sized egg to wingless
caterpillars and into colourful flying creatures. Every stage of butterfly is a rebirth to newly transformed form. In the lifecycle of
butterflies, the most of the time is spent on the caterpillar phase ranging from few days to several months. As the caterpillar
grows larger, they shed their outer skin by the process of moulting. Caterpillars usually moult four or five times as they grow.
Each different caterpillar stage after moulting is called an instar.
Caterpillar is an eating machine whose only purpose is to eat and grow. To achieve the purpose, caterpillars have to undergo
different scenarios which are answered here through some interesting questions.
How many legs does a caterpillar have?
A caterpillar has eight pairs of legs. The forward
three pairs of jointed legs with hooks are attached to
their thorax region and are called True Legs/ Thorac-
ic legs. These legs will become the legs of the adult
butterfly during metamorphosis. Behind true legs are
five pairs of Prolegs/False Legs attached to the abdo-
men. On the tip of each proleg is a ring of tiny, hook-
like structures called crochets. These facilitate the
caterpillar’s movement, allowing it to easily cling to
plant material, but they are discarded when the
butterfly develops. Four pairs of prolegs in abdomen
region is called as abdominal Proleg and the last pair
of prolegs near the end of the caterpillar is called
anal proleg.
How do caterpillars breathe?
Caterpillar breathes through nine pairs of pores or holes
(spiracles) on the sides of the body. The largest spiracles are locat-
ed on the thorax, where muscles from the legs and wings require
more oxygen. These holes connect to a network of long air tubes
(tracheae), and body movements pump the air through the tubes.
Caterpillars and even pupae breathe in a similar way, through
holes in their sides. The tracheae bring oxygen to the cells, and
carbon dioxide simply diffuses straight out of the tissues through
the exoskeleton.
What do caterpillars eat?
Caterpillars of most species are herbivorous feeding on
leaves, flower and stem and very few butterflies like
Apefly and Redspot are insectivorous. Some butterfl y
caterpillars like Crimson Rose, Common Hedge Blue,
Common Pierrot and Striped Pierrot are sometimes
found to be cannibalistic. Caterpillar feed on the leaves
of specific plants called as host plants. Each species of
Caterpillar can have one to many host plants belonging
to several families. Caterpillars can sometimes be found
on plants that are not their hosts, but this usually means
they are diseased, parasitized, or ready to pupate. Al-
most all caterpillars are voracious eaters, growing quickly
to as much as 1,000 times their birth weight.
Some caterpillars which are unable to find their pre-
ferred food plant will starve rather than switch to other
plants that are present in their habitat. Those that can-
not switch are called specialists. And some caterpillars
that can adopt new food plants and will accept more
than one host plant are called polyphagous.
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A TNBS MAGAZINE
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