BIOLOGY OF THE HONEY BEE

THERE are many kinds of wild bees, some of which are solitary in habit, while others, such as the Humble Bee and Honey Bee, are social and form populous communities. A hive of bees is a highly organized society of insects all working for the common good, and in this society there are three kinds of individuals. In each hive there are many thousands of worker bees and two or three hundred drones, but only one queen bee, making a total of from fifty to eighty thousand bees in all. The drone or male bee is larger than the worker and about the same size as the queen, but is more stoutly built. The queen is the egg-laying female and can be distinguished from the drone by her long pointed abdomen, which extends beyond the wings when these are folded over the back. In this position the wings of the drone are longer than the abdomen. At the end of the abdomen of the queen there is a pointed process called the ovipositor, which is used for depositing the eggs. The ovipositor is also connected with a poison bag and may be used as a sting. The worker is a sterile female and is smaller than the drone or queen.

THE LIFE HISTORY OF A FIIVE OF BEES

The Swarm

It is convenient to start the life history of a hive of bees with the swarming that takes place in May or June when there is more than one queen in the colony. On a warm day a swarm of bees consisting of an old queen and several thousand workers leaves the hive after gorging honey, and eventually settles in a dense cluster on the branch of a tree or bush. While swarming the bees are less likely to sting, and the hanging swarm is easily ’taken ’in a flat basket by the bee-keeper. A sheet is placed leading up to the entrance of the hive and the bees are shaken out of the basket on to this. Following the queen they soon crawl up the sheet and disappear into the hive. If the hanging swarm is not ’taken, ’ ’scouts ’look for a suitable 52 place and when they ’report ’their sucoess the bees fly off and make their home in a hollow tree or some other suitable place.

Comb Construction

Once inside the hive the workers clean it out, and if there is any animal within it which they cannot remove, they embalm it by injecting it with poison from their stings, and then cover the carcase with a gummy substance termed propolis or tree-gum. The workers then commence to secrete wax, which is made from the honey that they have eaten by glands situated on the underside of the abdomen, and appears as thin plates which are pushed out between the segments. The plates are removed from the abdomen by wax nippers on the hind legs, and the wax is passed forward to the mouth where it is moulded by the jaws. The workers then build combs constructed of many thousands of small, six-sided boxes called cells. Each comb is built vertically and has two layers of cells fitted back to back and arranged in rows so that each cell slopes slightly upwards. The queen lays an egg in each cell, and during May and June may lay as many as 3,500 in twenty-four hours, while in the course of her life of four or five years she lays hundreds of thousands of eggs.

The combs in which the workers are reared are termed brood combs, and occupy the lower parts of the hive. The central parts of a brood comb are usually occupied by developing larva? and pupa?, and are surrounded by a number of cells containing pollen, while the rest of the comb is used as a honey store. The upper combs in a hive are filled entirely with honey, for the queen is prevented from laying eggs in the cells of these combs by a thin sheet of metal called a ’queen excluder, ’ which lies horizontally below them. This sheet is perforated by numerous holes which are large enough to allow a worker to pass through but too small to permit the passage of the queen.

The Life of the Worker Bee

In about three days each egg hatches into a tiny white grub or larva which is fed by the workers with a secretion from their ’salivary glands. ’ This food, or royal jelly as it is called, is rich in protein and is poured into the cell so that the larva is actually floating in it. After the third day the larva is fed with bee-bread—a mixture of pollen and honey. At the end of six days the larva stops feeding and the workers cover the cell with a lid of wax and pollen. The larva then spins a sheet of silk which forms an imperfect cocoon and remains unchanged for two days, when it changes externally into a pupa. During the next week it becomes reorganized internally and emerges as an imago which gains its freedom by biting through the lid of the cell. The development from egg to perfect insect takes about three weeks in all. In summer the worker lives for about five weeks more before dying of overwork, for when her wings are worn out and her body has become bald through activity, she is no longer of any use to the hive and usually flies away to die.

During the first ten days of her existence outside the cell the worker remains inside the hive, and her first duty is to clean out the cells and lick the walls with her saliva. When about three days old she feeds the older grubs with honey and pollen from the store cells. As mentioned previously, the younger larva? are fed with a secretion called royal jelly secreted by the workers ’ salivary glands. These develop and commence to secrete when the worker is about six days old, and then she acts as nurse to the younger grubs. The glands shrink after the tenth day, and then the worker ceases her nursing duties and receives nectar from the bees which have visited flowers. She stores the nectar in the honey cells and also helps to pack the pollen into the pollen cells. About this time the wax glands of the worker have become active and commence to secrete wax with which she builds new cells. After constructing cells for several days the worker takes up a new duty as guard inside the entrance to the hive. Several guards are always present at the entrance and they inspect with their feelers each bee that enters. They also prevent bees from other hives from entering the hive and will sting any animal which attempts to interfere with it. During their period of guard duty the workers take short exploratory flights, but not until the twentieth day do they commence to collect pollen and nectar.

After the worker has handed over the nectar which she has collected to one of the younger workers, she performs a peculiar little dance on the comb. Taking rapid steps, she runs in small circles, first in one direction and then in another. This dance causes the surrounding bees to crowd round, and they run after her trying to touch her with their feelers. The worker may dance for a few seconds or for a minute, and may repeat the dance in another part of the hive before flying off to fetch more nectar. The dance is performed each time she returns with a full load of nectar. At first sight it looks as if the worker during the dance is somehow telling the others the position of the nectar-bearing flowers which she has just visited. It has been shown that this may be the case ; the dance signifies that nectar has been found, and indicates to the bees where the nectar is to be found.

The Cells of the Drone and Queen

The cells in which the drones are raised are similar in shape to the worker cells but slightly larger. The drone develops from an unfertilized egg and the drone larva is fed on royal jelly for three or four days, and afterwards is reared on a mixture of pollen and honey called bee-bread. The development of the drone from egg to perfect insect takes a little longer than that of the worker. In summer the workers alter several worker cells containing young larva? of varying ages, changing them into queen cells, which are hollow, oval structures opening downwards and usually placed on the lower edge of the comb. The queen larva is fed entirely on royal jelly and its development takes sixteen days.

While the young queens are developing, a swarm generally leaves the hive with the old queen, so that for a short time the hive is without a mature queen. The first young queen to crawl from the cell is helped by the workers to kill the other queens which have not emerged, and then leaves the hive for the nuptial flight, during which she receives sperm from a drone. On returning to the hive the new queen commences egg-laying. At the end of the summer the drones are killed or driven out by the workers, and the bees pass the winter clustered in the hive and feeding on the stores of honey and pollen. There is a constant circulation of bees in the cluster, for those inside it come out to get food and those outside push in for warmth. If the winter is cold and long it frequently happens that many of the bees die. With the return of spring the workers first clean out the hive, and then commence to collect pollen and nectar from the spring flowers. Old combs are repaired, new cells are built, and the queen starts to lay eggs again, so that the population rapidly increases.

The Mouth-parts

The mouth-parts of the bee are adapted for sucking up nectar from flowers. Projecting from the fused second maxilla; is a long tongue-like process called the ligula, which has a spoon-shaped depression at its tip. On each side of the ligula lies a jointed labial palp which helps to make a tube or proboscis up which the nectar is sucked. The first maxilla? are blade-shaped and lie one on each side of the proboscis, thus forming a protective case. When not in use, these mouth-parts lie in a groove on the under side of the head. The mandibles have a blunt toothless edge, and are used for kneading the wax into suitable shapes and for manipulating masses of pollen grains before they are made into the paste called bee-bread on which larvas and young workers feed. They are also used for softening vegetable resins and gums obtained from trees so that they can be used to stop up and make waterproof all holes in the hive. This material when set is termed tree-gum or propolis.

Honey

The weak sugary solution called nectar is quite different from the honey which is made from it, which is thicker and has a smaller proportion of water.

The nectar sucked UP by the bee is passed down the oesophagus to the honey stomach which acts as a storage chamber. In the honey stomach the nectar loses a certain amount of water and becomes altered in chemical composition, the salivary glands producing an enzyme converting the complex sugar of the nectar into simple sugars before it is regurgitated from the mouth into the cells as honey. This honey is still too watery, and to help the evaporation of water the workers stand in lines near the entrance to the hive and by the fanning of their wings cause a current of air to enter and leave the hive.. Also it has recently been discovered that the queen bee ’s ’salivary glands ’produce a substance which is distributed over the surface of her body. This is eaten by the workers when they comb and ’dress ’the queen and prevents the development and functioning of their ovaries.

The Collection of Pollen

Besides obtaining nectar from flowers the worker also takes pollen, and her hind legs are specially modified for collecting and carrying the pollen. When visiting a flower for pollen the bee scrapes the pollen from the stamens with her jaws and front legs, so that the body becomes dusted over with pollen. The pollen sticks to the hairs which cover the body of the bee, and collects in the greatest quantity on the under side. The fifth joint of the hind leg has on its inner side nine rows of short, stiff hairs forming a pollen brush with which the bee scrapes off the pollen from the underside of her body.

On the outside of the fourth joint of this leg is a hollow fringed by long hairs called the pollen basket, which forms a receptacle in which the pollen is carried. When the pollen brushes are full the hind legs are crossed and the pollen is scraped from the brushes into the pollen baskets, into which it is well pressed down by the second legs. If the bee is fully loaded large pollen masses can be seen projecting from the pollen baskets on the hind legs. On returning to the hive the bee prises the pollen out of the baskets into the cell by means of a spine or pollen prong on the second leg. A bee which is collecting pollen does not often collect nectar at the same time, and during an excursion the pollen baskets are loaded with pollen from one kind of flower only.

The hind legs of the queen and drone are not modified for collecting pollen.

Practical Work on the Honey Bee

Examine a larva, pupa and imago.

Examine and compare a queen, a worker and a drone.

Examine the legs of a worker bee with die low power of the microscope and make out the structural adaptations for collecting pollen and dealing with wax.

Examine under the microscope a prepared slide of the mouth-parts of a worker bee.

Examine the inside of a hive, and also the structure of honeycomb, brood comb and queen cells.

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