Honeybee Life Cycle and Anatomy

life-cycle-bee

Honeybee life cycle is a complete metamorphosis; they go through four life stages namely; egg, larva, pupa and adult. The castes have different development times as shown:

                                Days after laying egg
StageWorkerQueenDrone
Egg333
Larvae657
Pupa12814
Adult211624

The Larva

After the embryo develops, a larva hatches from the egg. Larva goes through five stages of growth (instars), modulating after each instar. Since the bee larva lack eggs, they eat food given by the nurse bees. They feed on royal jelly for the first three days after hatching.

Later on, the drone to be and the worker to be larvae are fed on nectar and pollen, while the queen continues feeding on royal jelly only.

Pupa

Antennae, legs and wings of the pupa form at this stage. Compound eyes and the adult mouth parts are also present. The fully formed pupa sheds its cuticle and does not change further externally.

Adult

Once the adult is complete within the pupa, it will split the pupal shell for the adult honey bee to emerge.

From the time eggs are laid, queens emerge after sixteen days, workers after twenty one days and drones after twenty four days (table above).

Honeybee Anatomy

The honey bee has segments in nearly all their body parts with an exoskeleton, mainly composed of chitin. They have an open circulatory system; all their internal organs bathe in a liquid called hemolymph.

They breathe through a network of tracheae and air sacs. Oxygen enters the body through spiracles by a compression mechanism.

The Head

Carries two compound eyes, three simple eyes (ocelli), which provide information about light intensity, two antennae and the feeding organs. The feeding organs are adapted to the ingestion of pollen (by mandibles) and liquids (by proboscis). The head joins the thorax by a flexible slender neck.

Compound Eyes

They form because of repeated units called ommatidia, each of which functions as a separate visual receptor. Worker bees have 4,000-6,000 ommatidia but drones have more since they require better visual ability during mating.

The Thorax

It has four segments, namely; prothorax, mesothorax, metathorax and propodeum. The prothorax carries the first pair of legs. the mesothorax and metathorax in addition to carrying each pair of legs support the two pairs of wings.

The legs

Honeybee legs have claws on the last tarsomere allowing them to move on rough surfaces like tree trunks, and have a soft pad (arolium) to walk on smooth surfaces like leaves.

The worker bees legs are modified to enable them collect pollen. Their hind tibia have long, curved hairs and the space is enclosed called pollen basket or corbicula.

On the tarsus are the pollen brushes and pollen rakes which are used for dislodging pollen from pollen baskets to the comb cells.

Abdomen

This contains the main viscera of the insect such as the stomach, intestine and reproductive organs. It also bears the external mating and egg laying organs.

It has nine segments. Each segment has a large back plate (tergum) and a smaller ventral plate, the sternum.

On the abdomen are wax glands, the scent glands and the sting. The sting of a queen bee is curved and is used to sting other rival queens in the colony.

At the tip of the abdomen there are nasanov glands which produce a material made of several compounds. This material helps bees to easily find the entrance of the hive and is useful in swarm site selection, and in reorientation of the bees when they lose the way to the hive.

Biological Systems of Honey Bees:

Alimentary canal

A bees digestive system plays the crucial role in nectar collection and transfer, honey maturation and in hive hygiene. The mouth opens into a cavity of the sucking pump which stands vertically in the head. The pump narrows to the slender, tubular oesophagus which turns through the neck and thorax, and the anterior end of the abdomen enlarges into a thin walled sac called honey stomach which is used by the bees to carry nectar or honey. Next is a narrow part called proventriculus which controls entrance of food into the ventriculus, a long, thick, cylindrical sac (true stomach), which is responsible for digestion and absorption of food.

After the stomach is the intestine. The intestine has two parts: anterior which is looped or coiled and posterior intestine (rectum) which is large and pear shaped. It is responsible for absorption of water and storage of waste matter and opens through the anus into the cavity that contains the sting. Malphigian tubules collect nitrogenous compound (uric acid) from the body cavity and excrete them into the digestive system.

Circulatory system

Bees have one blood vessel from the abdomen to the head. It transports nutrients from the abdomen to all parts of the body. The abdomen will constrict to force blood into the head region. The blood stream will carry Carbon (IV) oxide and disperse it through the membranes between the abdominal segment.

Respiratory system

Air enters the body of the bee through the spiracles. The spiracles have hair which prevent dust particles and other microorganisms from entering the respiratory system. Air is directed to the trachea from there.

Nervous system

Bees have loops of nervous cells. They have interconnecting membranes called ganglia. The ganglia at the head serve the head region. There are nerves all over the body and the antennae monitor the environmental changes and sensory hairs to detect sound. Honey Bees use pheromones to communicate.

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