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Caterpillar– The Eating Machine
Why do ants get attracted to caterpillars?
Although ants are among the leading invertebrate predators,
many butterfly species interact with ants in a relationship that is
mutually beneficial (myrmecophily). More than half of the spe-
cies of lycaenid butterfly larvae live peacefully with ants, usually
excreting sugary, carbohydrate-rich droplets from a gland on
their backs that the ants consume. The ants, in return, patrol
the surrounding plants and attack predators and parasitic wasps
that approach the caterpillars. Some larvae release chemical
signals that warn the ants of impending danger and some make
warning sounds. Caterpillars of some other species eat the im-
mature ants (eggs, grubs, and pupae).
Glands that help in the Symbiotic relationship between butterfly
caterpillar and Ant
* Pore cupolas glands are small, single-celled glands scattered
over the surface of all lycaenid caterpillars. The chemical secre-
tions produced by the glands can help in attracting, alerting or
deterring ants.
* Dorsal nectary organ (DNO)/ Honey Gland is a large special-
ized gland that secretes the nectar-like nutritious droplets con-
taining sugars and amino acids. This secretion attracts ants to a
caterpillar and in return, Ants offers protection to larvae from
predators.
* Tentacular organs (TOs) are two eversible structures which secrete volatile substances that both attract and alert ants when
the larva is alarmed or the DNO is depleted. They seem to function in ant-caterpillar communications.
How do caterpillars protect themselves from predators?
Caterpillars use different strategies and techniques to protect themselves from evading predators.
• Some caterpillars are poisonous to predators. These caterpillars get their toxicity from the
plants they eat. Generally, the brightly coloured larva are poisonous; their colour is a reminder
to predators about their toxicity. Some poisonous caterpillars include the Plain Tiger and Com-
mon Crow.
• Some caterpillar like Common Baron blends into their surroundings extraordinarily well. Many
caterpillars are a shade of green that matches their host plant. Caterpillars of Common Mor-
mon, Common Lime look like bird droppings (inedible objects).
• Some caterpillars have eyespots that make them look like the face of a much larger animal
(snake) and may scare away some predators. An eye spot is a circular, eye-like marking found
on the body of some caterpillars.
• Some caterpillars mostly Hesperiidae, encase themselves in a folded leaf or other hiding place.
This strategy protects them from the predator. Caterpillars of Red Pierrot bores inside the
leaves of the Host plant to escape from predator attack.
• Some caterpillars can emit very bad smells to ward off predators. They have an osmeterium,
an orange, y-shaped gland on their neck which gives off a strong, unpleasant odour when the
caterpillar is threatened. This keeps away dangerous wasps and flies that try to lay eggs on the
caterpillar.
PATTAMPOOCHI
A TNBS MAGAZINE
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