THE WORLD OF THE BUTTERFLIES
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INTRODUCTION TO THE WORLD OF BUTTERFLIES Their colours are produced chemically by pigments, and physically by diffraction and refraction of light. Both butterflies and moths display a surprising variety of colours, sizes and shapes. Their immense diversity and capacity to adapt to whichever climate places them amongst the most evolutionarily successful animals on earth. Their habitats vary from the Antarctic tundra to the tropical rainforest. The tropics contain the greatest variety of species because the most favorable conditions are to be found there: a hot climate and plenty of food. Being insects, butterflies have the basic characteristics of this group. The body is divided into three clearly different parts: head, thorax and abdomen. The head carries the antennae, coiled proboscis, the palpi and compound eyes. The thorax, divided into three segments carries three pairs of legs and two pairs of wings. The abdomen is made up of ten segments, although only eight are clearly visible. Basic Anatomy of the Butterfly: |
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| BUTTERFLIES OR MOTHS?
............................................................................................................................................ BUTTERFLY MOTH BIOLOGICAL CYCLE THE EGG: Following fertilization, the female deposits her eggs on, or near the plant where the larvae will subsequently feed. The plant she lays her eggs on depends on the species. They are laid either in groups or singularly, on or under the leaves. The eggs vary greatly in shape and appearance. Females lay from several dozen to some hundreds of eggs. In temperate and cold regions the ova either hibernate, (the caterpillars hatching in the spring), or they hatch a few days or weeks after the eggs have been laid. THE CATERPILLAR: The egg darkens in colour and it is possible to see the tiny caterpillar moving inside before eclosion. It cuts a flap in the hard egg casing and, once it has hatched, it usually eats the remaining shell which contains useful nutrients. This voracity is characteristic throughout the larval stage. The caterpillar stage is the only one in the butterfly life-cycle in which there is growth, and this is great: from the moment the caterpillar hatches, to its transformation into a chrysalis, it can increase its body size 20 times, the width of its head 6 times and multiply its weight up to 10,000 times! All this growth can take place in just a few weeks, or less. But even the most elastic of skins cannot cope with this increase. The caterpillar solves the problem by shedding its old skin four or five times, producing a larger replacement skin. THE CHRYSALIS: Once it has reached its maximum size, the caterpillar looks for a safe place where it will hang by a firm base made of silk, or attach itself to a leaf or twig with a silk girdle round its middle. Now it moults for the last time and reappears as a chrysalis. It is totally inert, and does not feed. Nevertheless, this external activity contrasts strongly with what is going on inside. The fastest transformation of the butterfly cycle occurs in this stage of the metamorphosis. Within the pupal shell, the tissues of the caterpillar are broken down and reconstructed into an adult butterfly. The majority of chrysalises take a few weeks to develop. Shortly before the adult emerges, the chrysalis “colours up” and the new butterfly within, is visible. THE ADULT: After emerging, the butterfly hangs upside down with its wings wet and limp. It then starts to inflate its wings, pumping them with blood. Once they have reached full size and are dry, the butterfly can fly and feed. Most importantly, it will look for a partner with which to reproduce. Butterflies have an alliance with flowers in order to obtain nectar or pollen. In exchange for food, they pollenise the flowers. Some species feed on rotting fruit, and others on dead animals or the sap from trees.
SURVIVAL AND PREDATORS Birds, lizards, mice and other insectivorous mammals, predator insects such as wasps and ants etc. PREDATORS OF ADULT BUTTERFLIES Birds, frogs, bats, spiders, other insects. Caterpillar Defense Systems • Unpleasant taste Chrysalis Defense Systems • Imitation of a leaf or branch Butterfly Defense System • Strategies for surprising or frightening: escaping by flying away is primordial but displaying false eyes on the wings can also put an aggressor off. The contrast between the ventral and dorsal wings is used as a surprise strategy (the Morpho butterfly).
CONSERVATION The tropical rainforests, with their enormous variety of plants and animals is the richest habitat for butterflies. But the incessant destruction of these forests for agriculture, and tropical wood supplies has put many species in danger of extinction. The apparition of butterfly parks is one initiative which could substitute the needs of collectors in the same way that photography has substituted safari hunting. In these centers, where multitudes of species, mostly tropical, are bred, people can contemplate, and photograph the most beautiful butterflies flying in their natural habitat. |
