Characteristics of varieties of caterpillars

16/03/2010

Maneka Gandhi

(Bihar Times)During a particularly horrible day in Parliament, I came home to answer the 779 ( true!) “ red coded emails ( all my animal emails are coded . Red is emergency, blue is half-done , green is article ideas and the rest of the 8500 of this year have been dealt with ). I found a green from a staffer on the 20 most poisonous caterpillars. Wondrous pictures , reinforcing my belief that God employs a huge army of artists, enough to make you forget about the ugliness of man and his creations.

All of us love butterflies. But how many of you have noticed ,or thought about, helping caterpillars. Do you plant the flowers that act as food for them ?

A caterpillar is the baby form of a butterfly or a moth. But few people let the caterpillar live: treating it as a nasty garden insect that eats their leaves. They use pesticide or squash it. But if you don’t let the baby live, how will you get the butterfly or the plant pollinated by the butterfly?

In any case , caterpillars are so interesting in themselves. Here are a few little known facts:
Butterflies and moths start out as eggs. These hatch into caterpillars, go through a pupa stage and then evolve into the winged version. The cycle can take as little as 3 weeks in the tropics and many months in colder climes. The Woolly Bear Caterpillar in the Arctic takes 14 years to reach adulthood as a moth !
A caterpillar has a head and 13 body segments. Three pairs of real legs and five pairs of sucker-like false legs at the back, with hooks for grabbing. It breathes through small holes on its back. It has 12 eyes but relies on its antennae for navigation. Human beings have 629 muscles. Caterpillars have 4,000 with 248 muscles in the head alone. As the caterpillar grows , it periodically sheds the skin as it becomes too tight. Caterpillars have very sensitive hair on their bodies that notice the change in the air if a flying insect comes near, detecting a wasp half a meter away.

Some caterpillars eat as much as 27,000 times their body weight. The caterpillar of the Polyphemus Moth, eats 86,000 times its weight at birth in two months. If a human baby weighed 9 pounds at birth and grew at the same rate as a caterpillar, it would weigh 243,000 pounds when fully grown ( I think I am nearly there!).

Like all beings on this planet, the purpose of a caterpillar’s life is to eat and not be eaten and to defend its life and property. How do they do these things ?

Eastern Tent Caterpillars climb up a tree to a crotch of branches and build a silk tent for protection. They leave the tent during the day to feed , returning at night. As the caterpillars grow larger, the tent grows. It can get to be about two feet long.

The female common hook-tip moth lays dense groups of eggs on trees. Each caterpillar builds a small, silky tent on a separate leaf to protect itself while it feeds. These tent are worth defending, and stealing. As the intruder moves onto the leaf, the resident caterpillar scrapes its oar-like hindmost legs over the leaf. If the intruder come closer, it adds mouthpart-drumming . The ferocity of a caterpillar's drumming may advertise its size and strength. Most disputes lasted a few minutes but can go on for hours. When caterpillar confronts caterpillar the leaf shakes !

Leafwing butterfly caterpillars form chains at the ends of leaves. They bind particles of their droppings together with silk into walls which provide protection from ants as the caterpillars rest.
Some caterpillars, specially those that live on croton leaves, “sing” generating a vibration that is transmitted through the plant. Ants hear these songs and are attracted to these insect sirens. The Croton plant feeds ants and caterpillars. The ants protect the plant from all insects except the singing caterpillars. The caterpillars develop "nectar organs “ which the ants drink from and they protect the caterpillar from predatory wasps.

Amazingly, the ants protect the singing caterpillars long before they develop nectar glands. And that is because the caterpillars use magic : they spray the ants with a mesmerizing substance from special "tentacle organs" near their heads !! In some species, ants carry the caterpillar into their nest, feeding it and being fed by its nectar glands.

How do caterpillars protect themselves ? Some do it through colour.Black, yellow and red are toxic and these warn off potential predators. In fact the brighter the colour, the more they are avoided.
Some do it with growing prickly hair or sharp spines. The io moth caterpillar has sharp spines with glands that secrete an irritating substance.

Some flex and rub their segments together to produce scary sounds.
A Swallowtail Caterpillar, if disturbed, will suddenly sprout bright orange “stinkhorns” from behind its head and give off a foul odor.
Some evade predators by using a silk line and dropping off from branches when disturbed.
The Puss moth caterpillar spits acid on predators.
Some leaf-rolling caterpillars fire faecal pellets from their anuses taking careful aim at their predators!
Tortricid Moth caterpillars protect themselves by rolling leaves which they then sealed with silk.
The ones that hide through mimicry are fascinating. Geometrid Moth caterpillars , when disturbed, mimic a branching twig by holding on with their prolegs and stretching themselves erect and holding perfectly still. They even have bumps on them that look like buds. The Berry caterpillars group around the top of a stem imitating the appearance of a poisonous berry.

Many caterpillars resemble the plants on which they feed and even have parts that look like Biological mimicry occurs when a group of organisms, the mimics, have evolved to share common perceived characteristics with another group, the models, through the selective action of a signal-receiver or dupe. Collectively this is known as a mimicry complex. The model is usually another species...

thorns. Some look like objects in the environment such as bird droppings.
Leaf miner is a term used to describe the larvae of many different species of insect which live in and eat the leaf tissue of plants. The vast majority of leaf-mining insects are moths and flies , though some beetles and wasps also exhibit this behavior.Like Woodboring beetles, leaf miners are...

Caterpillars of Nemoria arizonaria that grow in spring feed on oak buds and appear green. The summer caterpillars change to appear like oak twigs.
One carnivorous caterpillar species in Hawaii, hooks itself onto a leaf where it stands very straight and swats passing bugs ! Others make silken traps to catch snails.
Looper moth caterpillars move with curving their bodies into loops. They are also known as Inch Worms because they measure off exactly one inch at a time as they move !
Dermatitis is a blanket term meaning any "inflammation of the skin" . There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may be used to refer to eczema, which is also known as dermatitis eczema or...
Instead of just attracting passing butterflies to your garden with bright flowers, grow plants for caterpillars as well to encourage them to breed in your garden. Caterpillar food plants are leafy green plants with wide leaves, nasturtium leaves, dill, verbena, zininia, marigold, asters, chickweed, clover, hollyhock, lupines, mallows, milkweed, parsley, plumbago. Nectar plants are flowers which adult butterflies collect their food from. Host plants provide food for larvae after they hatch out of their eggs. Butterflies will lay their eggs only on host plants. Grow both.