Morphology, Anatomy and Functions Of Different Systems Of Cockroach

Introduction

Cockroaches are creatures with a brown or black body that belong to the phylum Arthropoda, class Insecta. In tropical areas, cockroaches with bright yellow, red and green colours have been seen. They feature a long antenna, legs and a flat extension of the upper body wall covering the head ranging from 0.25 inches to 3 inches (0.6-7.6 cm). They are nocturnal omnivores that dwell in moist environments all around the globe. They have become household pests and disease carriers.

Morphology of Cockroach

The common cockroach, Periplaneta americana, has wings that extend past the tip of the abdomen in males and is around 34-53 mm long as an adult. The cockroach’s body is divided into three separate regions: the head, the thorax, and the abdomen. A strong chitinous exoskeleton (brown in colour) covers the whole body. Hardened plates termed sclerites (tergites dorsally and sternites ventrally) are linked to each other by a thin and flexible articular membrane in each segment of the exoskeleton (arthrodial membrane).

Head

• The head is triangular in form and sits in front of the body at a right angle to the longitudinal axis of the body
• It is made up of the fusion of six segments and has a flexible neck that allows it to move freely in all directions
• A pair of complex eyes can be seen on the head capsule
• Membranous receptacles in front of the eyes sprout a pair of thread-like antennae, Sensory receptors in antennae aid in environmental monitoring
• Appendages on the anterior end of the skull produce biting and chewing mouthparts. A labrum (upper lip), a pair of mandibles, a pair of maxillae, and a labium make up the mouthparts (lower lip)
• A flexible middle lobe acts as a tongue (hypopharynx)

Thorax

• Prothorax, mesothorax, and metathorax are the three sections of the thorax
• The neck is a short extension of the prothorax that connects the head to the thorax
• A pair of walking legs are attached to each thoracic segment
• The mesothorax produces the first pair of wings, and the metathorax produces the second pair
• Tegmina (mesothoracic forewings) are opaque black and leathery forewings that cover the hind wings while at rest
• The hind wings are translucent and membranous, and they help the animal fly

Abdomen

• Both males and females have ten segments in their abdomen
• The 7th sternum is boat-shaped in females, and it creates a brood or genital pouch with the 8th and 9th sterna, which includes the female gonopore, spermathecal pores, and collateral glands in the front section
• The genital pouch or chamber is located at the back end of the abdomen in males and is bordered dorsally by the 9th and 10th terga and ventrally by the 9th sternum. Dorsal anus, ventral male genital hole, and gonapophysis are all found here
• Males have a pair of short, thread-like anal styles that females lack
• The tenth segment of both sexes has a pair of anal cerci

Anatomy and Functions of Different Systems of Cockroach

Anatomy

The cockroach anatomy includes digestive, circulatory, and reproductive structures and the structures that are present inside their skin.

Different Systems of Cockroach:

• Digestive system
• Circulatory system
• Respiratory system
• Nervous system
• Excretory system
• Reproductive system

The Digestive System of a Cockroach

The alimentary canal is separated into three sections in the body cavity: foregut or stomodeum, midgut or mesenteron, and hindgut or proctodaeum.

• The mouth opens into a small tubular pharynx, which leads to the oesophagus, a tiny tube conduit. This expands into a sac-like structure called a crop, which is used to store food
• The gizzard assists in the crushing of food particles. Gizzard or proventriculus possesses a thick outer layer of circular muscles and a thick inner cuticle that forms six teeth-like chitinous plates
• Cuticle covers the whole foregut. At the confluence of the foregut and midgut is a ring of 6-8 blind tubules termed the hepatic or gastric caeca, which release digestive juice
• Another ring of 100-150 yellow-coloured thin filamentous Malpighian tubules can be found at the midgut-hindgut junction. They aid in the elimination of excretory waste from the haemolymph
• The ileum, colon, and rectum make up the hindgut, which is larger than the midgut. Through the anus, the rectum opens up

The circulatory system of a cockroach

Cockroaches have an open blood circulatory system

• The blood vessels are underdeveloped and open into the air (haemocoel). The blood bathes the visceral organs in the haemocoel (haemolymph). Colourless plasma and haemocytes make up the haemolymph
• The cockroach’s heart is an extended muscular tube that runs along the mid-dorsal line of the thorax and abdomen. It is divided into funnel-shaped chambers into both sides by Ostia

• Through the Ostia, blood from the sinuses enters the heart and is pumped anteriorly to the sinuses

The Respiratory System of a Cockroach

The respiratory system is made up of a network of the trachea that open through ten pairs of tiny openings on the body’s lateral side called spiracles. Air is carried to all regions of the body by thin branching tubes as tracheal tubes split into tracheoles. Diffusion occurs at the tracheoles to exchange gases.

The Nervous System of a Cockroach

On the ventral side, the cockroach’s central, peripheral and sympathetic nervous systems are made up of a series of fused, segmentally organised ganglia connected by paired longitudinal connectives. The thorax has three ganglia, while the abdomen has six.

The Excretory System of a Cockroach

Malpighian tubules are responsible for excretion. Glandular and ciliated cells line each tubule. They take in nitrogenous waste and convert it to uric acid, which is then expelled through the hindgut.

The Reproductive System of a Cockroach

Cockroaches are dioecious, with reproductive organs in both sexes. Male: The male reproductive system is made up of two testes, one on each lateral side of the 4th and 6th abdominal segments. A narrow vas deferens emerges from each testis, and through the seminal vesicle, it connects to the ejaculatory duct. The male gonopore is located ventral to the anus and opens into the ejaculatory duct. The sperms are retained in the seminal vesicles and cemented together in spermatophores, which are expelled during copulation. Female: Two enormous ovaries lie laterally in the 2nd-6th abdominal segments, forming the female reproductive system. Each ovary is made up of eight ovarian tubules, also known as ovarioles, which contain a chain of growing ova. Each ovary’s oviducts join to form a single median oviduct (also known as a vagina), which opens into the genital chamber. Spermatophores are used to transport sperm. Their fertilised eggs are wrapped in oothecae capsules. They’re dropped or bonded to a suitable surface near a food supply in a crack or fissure with high relative humidity. Females produce 9-10 oothecae on average, each holding 14-16 eggs.

Conclusion

This article acts as the morphology, anatomy and functions of different systems of cockroach study material. To understand the basic concepts, we have to understand tissues and their connection to one another. The cockroach anatomy includes digestive, circulatory, and reproductive structures and the structures that are present inside their skin.