Essay on Honey-Bee

In this essay we will discuss about honey-bee. After reading this essay you will learn about:- 1. External Structures of Honey-Bee 2. Digestive System of Honey-Bee 3. Respiratory System 4. Excretory System 5. Circulatory System 6. Nervous System 7. Reproductive System 8. Development and Life History 9. Economic Importance.

Essay Contents :

1. Essay on the External Structures of Honey-Bee
2. Essay on the Digestive System of Honey-Bee
3. Essay on the Respiratory System of Honey-Bee
4. Essay on the Excretory System of Honey-Bee
5. Essay on the Circulatory System of Honey-Bee
6. Essay on the Nervous System of Honey-Bee
7. Essay on the Reproductive System of Honey-Bee
8. Essay on the Development and Life History of Honey-Bee
9. Essay on the Economic Importance of Honey-Bee

1. Essay on the External Structures of Honey-Bee:

Three tagmata of the body, namely, head, thorax and abdomen are provided with cer­tain specialised structures to help it in its peculiar habit.

A. Head:

The triangular head (Fig. 18.76) contains:

(1) Three ocelli in the middle,

(2) Two well-marked compound eyes, and

(3) Two short, many-jointed antennae and several append­ages around the mouth which are of rasping and lapping type.

These mouth parts in­clude:

(a) Mandible:

These paired spoon-shaped structures are very strongly built in worker bees and are used at the time of making of combs.

(b) First maxilla:

Each of the paired max­illae includes a lamina or galea on a basal piece which is composed of two elements— stipes and cardo. The maxillary palps are poorly developed.

(c) Second maxilla:

These paired append­ages form the lower lip. It is well developed in the workers. The proximal parts of the two maxillae are united. From the outer side of each second maxilla hangs a long labial palp. The inner side may be splitted into two parts—glossa and paraglossa. Two glossae, one from each second maxilla, are united to form the tongue or ligula.

The distal spoon­-like tip of the tongue is called labellum and it has a ventro-median groove. The paraglossa is firmly united with the base of the ligula. Three parts—labial palps, ligula and paraglossae form an airtight tube for sucking nectar. The elongated mouth parts, while not in use, are kept folded.

B. Thorax:

The thorax, as in other insects, consists of three segments—prothorax, mesothorax and metathorax. Each thoracic segment bears a pair of appendages in the form of legs. Two pairs of wings occur as non-appendicular structures. There are two pairs of spiracles—one pair in the mesothorax and the other on the metathorax.

Legs:

The legs have the same pattern as that of cockroach but are largely modified for their particular way of life (Fig. 18.77).

(1) Prothoracic legs:

Here the tibia of each leg is provided with soft hairs, called eye brushes, which are used for cleaning the pollens and debris from the eye. The stiff bristles, known as pollen brushes, are present on the first tarsal segment to work as an­tenna cleaner.

(2) Mesothoracic legs:

In addition to pollen brushes of the first tarsal segment, the tibia bears a wax spine stick for removing wax from the wax glands.

(3) Metathoracic legs:

The first tarsal seg­ment bears at its inner part pollen combs, which are responsible for collecting pollens from the pollen brushes of other legs. A structure, called pollen packer, is present near the junction to tibia and first tarsal segment.

This pollen packer is formed by a spiny pecten on tibia and a notched plate, called auricle, on the first tarsal segment. It cleans the pollen combs and deposits the pollens within pollen basket which is placed on the outer side of the tibia.

Wings:

Two pairs of wings are placed on the dorsal side of the thorax. The wings are largest in drones and smallest in queens. The wings are structurally same as that of cock­roach, but the mechanism of wing action during flight is peculiar and completely dif­ferent from most other flying animals.

The wings instead of mere flapping perform a speedy rotatory motion. Such action helps the bee to do various movements during flight, e.g., ascending, descending, remain­ing fixed and also backward movement. Aerodynamically speaking, the flight of honey bee resembles more with the helicopter than aeroplane.

C. Abdomen:

The number of segments in the abdomen is seven in drones but six in workers and queens. In drones, the abdomen is broad but smaller than the wings. In queens the abdomen is elongated and taper­ing. The abdomen bears several apertures, called stigmata, which are six pairs in drones and five pairs in queens and workers.

The workers bear on the ventral side four pairs of wax glands to produce wax. The wax is liberated through minute pores which form scales. In queens and workers the posterior-most end of the abdomen is provided with a sting which is connected to the inter­nal poison gland. The sting is formed by a dorsal stylet sheath and a pair of ventral lancelets.

These three pieces enclose an inner poison canal. At its proximal end the sting has a swollen bulb and a pair of bifid arms, one on each side of it. The distal tip is beset with spines, called barbs (Fig. 18.78). Three pairs of plates—oblong, fulcral and quad­rate, remain associated with the sting to act as lever.

From each oblong plate arises an elongated palp to enclose the sting. The poison gland is short and slender. Its secre­tion remains stored in a large poison sac, which opens to the proximal end of the sting near the bulb. In the queen, the sting also acts as an ovipositor.

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2. Essay on the Digestive System of Honey-Bee:

In addition to the mouth and pharynx, the alimentary canal consists of following parts—oesophagus, honey-sac, chyle stom­ach, small intestine, large intestine and anus (Fig. 18.79).

Straight and tube-like oesophagus passes through the thoracic re­gion. Within the abdomen the last part of the oesophagus dilates to become a honey-sac. The honey-sac opens to the chyle stomach. The opening is guarded by a complex stop­per.

The chyle stomach is broad, half-bent and leads to the small intestine. The opening is separated by a pylorus. The inner wall of the coiled intestine is lined by longitudinal rows of chitinous teeth. The sac-like large intestine is the posterior continuation of the small intestine.

The opening between small intestine and large intestine is guarded by valves of six plates. According to some workers the stopper and the chyle stomach are equivalents of proventriculus and ventriculus respectively.

The digestive glands are represented by three pairs of salivary glands. The saliva from these glands mixes with pollens and nectar. The enzymatic action converts the nectar into honey. It is either digested or regurgi­tated into the comb for future use. Another pair of coiled glands is present in the head of worker bees which produce a nitrogenous food, called ‘Royal jelly’.

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3. Essay on the Respiratory System of Honey-Bee:

The respiratory organs are tracheae. The arrangement of tracheae is same as in cock­roach and consists of stigmata, longitudinal trunks and segmental branches. In certain regions the tracheae are dilated to become air sacs.

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4. Essay on the Excretory System of Honey-Bee:

Numerous filiform tubules, called Mal­pighian tubules, serve as excretory organs. These tubules open into the lumen of the intestine through their proximal end and their distal blind end remains suspended within the haemocoelomic spaces. The excre­tory products pass out through the alimen­tary canal.

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5. Essay on the Circulatory System of Honey-Bee:

Tubular heart is present along the mid- dorsal region of the thorax and abdomen. The blood which is pumped by the heart flows through the haemocoelomic spaces. The blood is known as haemolymph and it possesses a few amoeboid cells with promi­nent nuclei.

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6. Essay on the Nervous System of Honey-Bee:

The nervous system is well developed in honey-bee. These insects possess extremely powerful sense organs and are well known for their power of communication which serves as the basis of their social life.

The gentral nervous system in honey-bee in­cludes:

(a) Prominent supra-oesophageal ganglion on the dorsal side of the head which is formed by the fusion of several ganglia,

(b) Sub-oesophageal ganglion on the ventral side of the oesophagus is formed by the union of three pairs of ganglia and

(c) A double ventral nerve cord, which begins from the sub-oesophageal ganglia and runs along the mid-ventral line up to the posterior end of the abdomen.

On each side the supra- oesophageal ganglion is connected with the sub-oesophageal ganglion by a connective. The ventral nerve cord along its path bears three pairs of thoracic ganglia and four (in drones and females) or five (in workers) pairs of abdominal ganglia. The peripheral nerves are given from these different gan­glia. From brain, the paired optic nerves arise as broad projections.

The important sense organs are antennae and eyes. The an­tennae bear special receptor cells for detect­ing smell and measuring distances. Both the simple and compound eyes are present.

The simple eyes are meant for detecting the in­tensity of light while the compound eyes are responsible for vision. It has been shown experimentally that honey-bees have special power for selection of colours. It can detect a few more colours in the infra-red and ultra­violet zone of the spectrum, which are invis­ible to the human eye.

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7. Essay on the Reproductive System of Honey-Bee:

The functional females are known as queens while the males are called drones. The workers are sterile females.

Male reproductive system:

In drones, a pair of testes is connected with a pair of narrow tubes, each of which is called vas deferens. The outer end of the vas deferens dilates into a seminal vesicle through which it opens within the ejaculatory duct. The copulatory apparatus is connected with the termi­nal end of ejaculatory duct.

A pair of promi­nent mucous glands opens at the point of union. When matured, the sperms come out of each testis and crowd near the end of the ejacu­latory duct. The sperms are transferred to the females in packets, called spermatophores.

Female reproductive system:

In the queen, the paired, tubular ovaries are present. In the matured state the ovaries are large and conspicuous. Each ovary contains several tubes and each tube contains eggs at differ­ent stages of maturity.

Each ovary communi­cates to an oviduct and the two oviducts unite to form a common oviduct. The inner end of the common oviduct is connected to a round vesicle, called spermatheca. The oviduct fi­nally opens to the exterior through a copulatory pouch.

Mechanism of reproduction:

Each hive contains one matured queen, several drones and innumerable workers. During reproduc­tion, the queen performs a nuptial flight with several drones. The drone which copu­lates with the female loses its copulatory apparatus and ultimately dies. The sperm cells remain stored in the spermatheca of the female.

The queen after returning to the hive starts laying eggs. The fertilization occurs only at this stage. The queen lays both unfertilized and fertilized eggs. The entire process is believed to be either under the voluntary control of the female or by the size of the cell of the hive, where the egg is laid.

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8. Essay on the Development and Life History of Honey-Bee:

The larvae hatch out of the eggs three days after laying (Fig. 18.80). The unfertilized eggs become drones and the fertilized eggs become either females or workers. The popu­lation of male, female and workers in a hive are controlled by differential feeding of the larvae. The controlling function is done by workers.

The future workers are feed with only honey. The would-be drones are given a mixture of honey and pollen grains (called the bee-bread) and the future queen is given the special food, ‘Royal jelly’. It is fed con­tinuously for five consecutive days with royal jelly. It results into the enormous increase in size. The larva at this stage produces a co­coon around its body and enters into pupa stage.

Inside the cocoon, rapid transforma­tion takes place and finally the adult gets out of the cocoon by cutting it. If several queens are produced, only one survives and others are eliminated.

The queen comes out at the end of fifteenth day, the workers after twenty-one days and the drones after twenty-four days. The worker bees after coming out of the pupal case start working and their duties are changed with the advancement of age.

The different works done by a worker bee is given below:

From 1st to 3rd days—it cleans the com­partment of the hive where it was born for using them again.

From 4th to 9th days—it works as a nurse and feeds the larvae with its own secretion or by honey produced by others.

From 10th to 11th days—it acts as a builder and constructs new cells in the hive by the wax produced by the wax glands.

From 17th to 19th days—it collects the nectars from the bees which bring it from the outside and converts it into honey. At this time, it also helps to cool the hive by fanning the wing. It also removes debris from the hive to clean it.

From 21st to 25th day—it works as a soldier and protects the hive from the inva­sion of enemies including the bees from the other hives.

From 25th day onwards—it starts to go out of the hive for collecting nectar and pollen from flowers. It is then known as forager. Life of a worker bee is about six weeks in European countries.

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9. Essay on the Economic Importance of Honey-Bee:

The use of honey and wax is known to man for a long time. As these two products come from bee-hive, the honey-bees are con­sidered by many as economically important. Bees are very economically important in connection with pollination to agriculturists. The abdominal body hairs and hairs distrib­uted all over the surfaces of their legs are mainly responsible for collecting the pollen grains.

The pollen grains are transferred from one flower to other during their honey col­lection and thus cause pollination. The bees while foraging, collect nectar and pollen from flowers. Within the hive, the worker bees drink the nectar. Inside their honey-sac, by the action of special enzyme, the cane sugar part of the nectar is converted into glucose (dextrose) and fructose (leevulose).

Constitution of honey:

454 g of honey contain 165 g fructose (fruit sugar), 142 g glucose, 9 g sucrose, 85 g moisture, 7 g dextrine and gums, 1 g of Fe, Ca, Na and about 4% undetermined substances. The honey thus formed is regurgitated and stored in the hive for future use. The honey is regarded as antiseptic and is believed to have profound medical importance.

Food value of honey:

454 g of honey is equal to 1.6 kg of potato or 2.0 kg of grapes or 1.4 kg of bananas or 6.0 kg of cauliflower or 2.3 kg of apples. It is also a very powerful tonic and compared to 365 u.g.—Vit. B (Thia­min), 268 u.g.—Vit. C (Riboflavin), 18 mg— Vit. C (Ascorbic acid) or 0.60 mg—Nicotinic acid.

The wax is produced by the wax gland of worker bees and is used to construct the hive. Two other products, propolis and balm, are also collected from various parts of the plants and are used in the construction of hive. The propolis is used as cement to bind broken parts and the balm is taken for pol­ishing inner walls.