The World Outside My Window Read online

  Nymphs grow by shedding their skin. They may have as many as seven new coats. When they mature, they crawl up water plants, shed their skin and emerge as flying adults.

  dragonflies are harmless to man. They are, in fact, of real value, because the nymphs eat mosquito wrigglers in the water and the adults catch the mosquitoes they find hovering over the water.

  The Firefly

  There was a time when many people in different parts of the world worked or studied by the fitful glow of a luminous insect—the firefly, or ‘jugnu’ as we call it in India. In China and Japan, for example, needy students often used to read right through the night by firefly light. It must have been a great strain on their eyes, for although the firefly’s glow appears brilliant to the human eye, its candlepower (the unit of light measurement) is extremely low. In fact, one scientist has estimated that it would take nearly forty fireflies to equal the illumination given off by a single candle. And yet, this little insect’s light-producing mechanism is more efficient than anything we have invented for the purpose, for the simple reason that practically no heat is generated, whereas in our artificial lighting methods there is always some wastage.

  But how does the firefly make its light?

  In the insect’s body there is a substance called luciferin upon which an enzyme (an organic catalyst) reacts, releasing energy in the form of light. There is nothing very strange about this. A rather similar thing happens when we eat: our enzymes react with the food, but in our case they release energy in the form of bodily heat and movement.

  Why do these insects need to give off light at all? The answer seems to be that in the darkness of tropical forests where most fireflies live, male and female fireflies are able to signal to each other from considerable distances, the two sexes each having well-defined flash sequences.

  In Japan, even today there are insect-dealers who breed and sell fireflies. Kept in large numbers in little gauze-covered cages, they form quaint and beautiful illuminations at parties and festivals. In many parts of Central and South America too, these little insects found use as primitive lanterns and ornaments. Early travellers to the West Indies relate how they saw black people working in their huts by the light of fireflies in perforated gourd lanterns.

  But perhaps the strangest story of all man’s uses of fireflies as natural lights comes from Java. It is in a kind of pocket light, consisting of a shallow wooden dish with a lid pivoted at one end. At the bottom of the dish is a layer of wax in which the fireflies are stuck. Extra ‘bulbs’—fireflies, of course—are kept in a cane tube. But the really unusual thing about this torch is that it is said to have been used by a burglar. It would probably have been very useful in such a profession, because the moveable lid could be closed over the fireflies when the light was not needed.

  It is perhaps worth mentioning that fireflies are not really flies at all; they are beetles. The glow-worm is also a beetle—though the female is more like a worm than her mate. In comparison with fireflies, glow-worms give off a very feeble glimmer.

  Like all beetles, and insects generally, fireflies and glow-worms pass through several distinct stages in their lives. First we have the eggs or ova; next, these hatch as larvae or grubs; then these turn into pupae, which is the final resting stage before the adult firefly emerges to find a mate and begin the whole sequence again.

  Most of the firefly’s feeding is done by the larvae, as by the larvae (or caterpillars) of butterflies and moths. Some firefly larvae feed on animal matter, others on vegetable. The glow-worm larva, for example, likes nothing better than a meal of slugs and snails; so it deserves all the protection it can get, especially from gardeners.

  Firefly in My Room

  Last night, as I lay sleepless

  In the summer dark

  With window open to invite a breeze,

  Softly a firefly flew in

  And circled round the room

  Twinkling at me from floor or wall

  Or ceiling, never long in one place

  But lighting up little spaces…

  A friendly presence, dispelling

  The settled gloom of an unhappy day.

  And after it had gone, I left

  The window open, just in case

  It should return.

  The Ladybird Beetle

  The ladybird beetle is familiar to almost everyone. Like a tiny, brightly coloured minicar, the little insect moves busily over leaves and grass blades, searching for food. Sometimes it turns up in surprising places; on the counterpane of one’s bed, or on the curtains or the inside of a windowpane.

  Ladybirds, like pills, come in assorted shapes, sizes and colours. Some are oval and some are round. Some are black with red spots and some red with black spots. All of them, however, have six short legs that carry them about with surprising speed, and a pair of dark wings. The wings are kept hidden beneath the two spotted wing-covers and are not usually visible when the ladybird is not using them.

  During spring the female ladybird beetle lays her eggs. They are not laid in a group like the eggs of many other insects, but each one is placed on the leaf of a plant. When the egg hatches, out crawls an insect that does not have any resemblance to the adult beetle. It is long and soft, and its legs look almost useless. However, these legs serve the larva, or young grub, in hanging on to a stem or twig. As soon as the larva hatches, it goes in search of food, eating mostly aphids and scale-insects that are very injurious to our plants. Like many other immature insects, the larva outgrows its skin and has to shed it. After several moults, it is ready to change into a pupa. In some secluded spot, it hangs upside down by its tail and sheds its skin for the last time; then the pupa appears with the old skin draped around the top. After a few days, the pupa skin splits and the full-grown ladybird emerges.

  The ladybird beetle is an insect that is very helpful to man, for both adult and larva eat some of the most harmful insects. Several years ago, the orange and lemon trees in Californian orchards were being ruined by a species of scale-insect. A new species of Australian ladybird beetle was introduced into California, and within a few years these ladybirds had destroyed the insect pests.

  Although the ladybird does not have many enemies, it protects itself quite successfully. If you touch one as it is running along the stem of a plant, it will probably fold its legs underneath its body, drop to the ground and lie as if dead for several minutes. Then, when it thinks the danger has passed, it will suddenly begin waving its legs frantically in an effort to right itself.

  Some will remember the nursery rhyme:

  ‘Ladybird, ladybird, fly away home,

  Your house is on fire, your children will burn.’

  There is not much truth to this, because the ladybird has no house and absolutely no interest in its children. The rhyme originated about a hundred years ago in England, when children used to spend much of their time watching ladybirds run about on the hop vines, searching for food. The children thought that the beetles lived there and so, when the farmers burned the hop vines, as they did every year, the children believed that the young ladybirds and their homes were being destroyed.

  The Honeybee

  Nearly everyone, from the ancient Egyptians to present-day engineers, has been impressed by the activities of the honeybee. The organization of the hive and the terrific energy of the bees themselves have been a source of wonder and amazement to man for hundreds of years.

  The dark interior of a beehive is the centre of many different activities. Although one hive may contain as many as 50,000 inhabitants, there is no confusion. Each bee performs tasks that are necessary for the survival of the whole colony. Most of the honeybees in a hive are worker bees. As their name suggests, these bees gather the nectar and pollen, make the wax honeycombs and care for the young bees. Although the worker bees are constantly busy at these many tasks, they alone could not keep the colony going for very long because they cannot lay eggs that will hatch into workers. In every productive hive there is one bee ca
lled the queen. She does nothing but lay eggs.

  The queen lays more than 3,000 eggs per day—unfertilized eggs for males (drones) and fertilized for females (workers and future queens). Her welfare is the constant care of the workers, and she is fed a ‘royal jelly’. Honey is stored in special cells for the support of the colony throughout the winter, when the drones or male bees are driven out of the hive to die.

  For many years men have provided artificial homes for honeybees and in return have taken honey and beeswax. Beeswax is used in many articles, from gramophone records to candles. The sticky golden liquid known as honey was probably the first sugar used by man. When you buy a pound of pure honey, it is hard to realize all the effort that goes into its production, but if you watch one of the worker bees for several hours, you might discover some of the facts about honey-making.

  When one of the worker bees leaves the hive to search for the nectar from which honey is made, it will probably cover several miles before it returns. Upon finding a flower from which nectar can be obtained, the worker hovers for a second and then alights, and moves across the petal of the flower until it finds the source of the sweet nectar. Using its tongue, which acts as a sucking tube, the bee draws the nectar into its honey-bag or crop. When it has exhausted the nectar supply of one flower, it flies on to another until its crop is full.

  On the flight back to the hive, many different substances in the bee’s body are already at work, changing the nectar into honey.

  Upon its return to the hive, the worker bee is met by several young workers, and the nectar, which now resembles very watery honey, is transferred to them. These bees then seem to mix the honey by forcing it in and out of their bodies several times. After this, the honey is ready to be stored in a wax cell and left until the excess water has evaporated. When the honey is thick and golden, the bees place a cap of wax over the cell, sealing it until the honey is to be used for food during the winter.

  Why do bees buzz, and why do they sting?

  The bee’s buzz is made by the movement of its wings. The wings vibrate very rapidly, as they move to and fro, and these vibrations set up waves in the air that carry the sound to our ears.

  A bee stings to protect itself or a hive from danger. It is the worker bee which has this duty of protecting the community. The stinger, a long, hollow tube with a barb at the tip, grows out from the rear of the insect’s body. When the bee needs to protect itself, a drop of poison is forced down the tube, the barb is driven into the enemy and the poison is discharged.

  A bee can sting only once, as a general rule, for when it tries to withdraw its stinger, the barb usually breaks off. Sometimes the stinger is so roughly torn from the bee’s body that it dies. But the queen bee’s stinger does not have a barb, and she can use it again and again to sting rival queens. The drone has no stinger. There are several sting-less bees, but some have a sharp bite.

  Miniature Insects

  Insects are among the smallest animals we notice around us. Yet the small body of an insect contains a brain, heart, muscles and other organs that function like those in the complicated body of an animal with a bony skeleton. Each kind of insect is equipped for living in a specific type of environment, and yet all this special equipment is packed in such a small body that we must use a microscope to examine the structure of most insects. It is not that insects cannot be bigger—the stick insect, found in India and other tropical countries, can be as much as a foot long, and millions of years ago there were dragonflies with bodies two feet long. The wonder is that there can be complex creatures so very small, yet perfect in every detail.

  There are even pygmy species in insect families too. Grasshoppers are generally quite big insects, just as man is one of the larger kinds of mammal. And, just as the pygmies are a group much smaller than the human average, so pygmy locusts are very small members of the grasshopper family—only half-an-inch long.

  A half-inch is about medium size for an insect. Most of the thousands of species that have been discovered so far are less than a half-inch long, and many are so tiny that they look like bits of moving dust to the human eye. Most flies, for instance, are rather small insects, and the tiny biting gnat is about as small as anyone can imagine. Its fiery bite is certainly out of all proportion to its size, which is no larger than a pencil dot.

  What is probably the smallest insect in the world is a European wasp, only one-tenth as big as a gnat. This is so very small that even the sharpest human eyes need the aid of a microscope to see it. However, living unnoticed all around us are many of its important cousins which, though twice as big, can barely be seen. These are named the egg-parasites.

  Naturally, all members of this family of wasps have to be extremely small, since they lay their eggs in the eggs of other insects—in this way, they make sure of a food supply for their young, and also prove themselves good friends of the farmers.

  This minute species is valuable to us because it so often selects the eggs of butterflies and moths whose caterpillars destroy our farm crops. The wasp larvae are parasites, hatching and growing inside the moth egg at the expense of the caterpillar, which dies before it can hatch and start damaging plants. In seven weeks, three female wasps of one species can have about 300,000 descendants, and so, uncountable thousands may be living on a single farm.

  Since there are egg-parasite wasps in all parts of the world where crops of grain, cotton and fruit grow, we are very fortunate to have them on our side in our struggle for more food.

  Some Insect Giants

  While insects do not compete in size with the higher animals, there are many species—giants of their class—which grow to impressive proportions. The largest insects that ever lived were the huge ancestors of our dragonflies, which in prehistoric times darted over the streams and pools of primeval forests. The impression of their wings and bodies preserved in the limestone rocks of the Carboniferous period have provided us with a record of their appearance. The largest of these insects measured two feet across its expanded wings. Our present-day dragonflies have a wing expanse of about six inches. They are small compared to their ancestors, and are harmless, except to the insects they prey on.

  Of all the curious and weirdly constructed creatures which are to be found in the world perhaps the strangest are the Phasmids, commonly known as stick and leaf insects. Their variety of form can hardly be surpassed. Some are like walking blades of grass, their bodies and limbs reduced to mere lines. Others are heavier in build, and imitate withered twigs. Others again have their bodies flattened out in the form of a leaf and impressed with veins and a midrib. So complete is the resemblance to a leaf that it is impossible to recognize the creatures except when they move.

  The largest of the stick insects in India is a giant, measuring eighteen inches in length from its head to the top of its abdomen. Its body looks and is coloured like a withered twig, while its sprawling ungainly legs help to heighten the resemblance. It is found in Assam and in the rainswept forests of southern India.

  Quite as remarkable as the stick insects are the mantis or praying insects. They are often uninvited guests at the dining table. The most familiar and perhaps the largest of the tribe is a robust green fellow about six inches long. His soft leaf-shaped abdomen is concealed under overlapping gauzy wings. His strong spiny forelegs, held over his head like two arms outstretched in prayer, are his most striking features. Hence the name praying mantis.

  A mantis will rest motionless on its perch for several hours, waiting for some small insect to come its way. Squatting on two pairs of legs, its foreparts held erect, the mantis watches and waits. It turns its head a little from side to side, attentively. An insect settles nearby. The mantis stiffens its body. Its head is held rigid, while its arms gradually reach out. Slowly and deliberately it advances within striking distance, and strikes quickly and vigorously. The victim is seized and held by the spiny arms, carried to the mouth and eaten.

  There are several giant grasshoppers, among them the ‘Bherwa�
�, common in Bihar, a bulky, wingless and rather unpleasant-looking creature, with an alarming mouth, long waving horns and sturdy legs. It lives in loose sandy soil, generally in the banks of rivers where it digs itself into a deep burrow.

  The beetle tribe has produced a few monsters, including the elephant beetle, the rhinoceros beetle, the stag beetle and the bamboo beetle. Other giants are the ‘Goliath’ from West Africa, and the West Indian ‘Hercules’. The largest butterflies are the swallowtails. The largest moth in India is the atlas moth, which has a wing expanse of ten–twelve inches. It lives in our hill forests and is a most beautiful and vividly coloured insect.

  In spite of their limitations in size, insects are dominant creatures which have increased and multiplied and almost possessed the earth. Their smallness in relation to other animals has been a distinct advantage to them.

  They are fast to develop, and faster to reproduce. The descendants of a single pair of flies produced within the space of a year runs into many thousands. Then again, thousands of insects can concentrate upon one point where food is aplenty, and in times of stress can scatter over wide areas, while large animals like sheep and cows, when faced with scarcity, die of starvation.

  This is why insects are able to make such a success of the business of living. Mere bulk does not protect a species: rapid increase will. Thousands may perish in adversity, but some will survive to carry on the race.

  Music in the Trees

  In India, the monsoon is the season when our insect orchestra is at its best. It is true that the shrill music of the cicada is heard throughout the hot weather; but theirs is a prelude to the great concert that comes into full play once the rainy season begins. When the monsoon with its magic touch brings life and greenness to rock and earth and tree, the whole air seems to come alive with the music of insects. Grasshoppers shrill in the bushes, crickets chirp from under stones, and in the water-laden fields there are hundreds of minor artists providing a medley of sounds.