Class 11 Biology

Anatomy of Cockroach

Blood Vascular System

  • The heart consists of elongated muscular tubes which lie along mid-dorsal line of thorax and abdomen. The heart is differentiated into funnel-shaped chambers, with ostia on either side.
  • circulatory system of cockroach
  • The blood from sinuses enters the heart through ostia and is pumped anteriorly to the sinuses again.
  • Respiratory System

    The respiratory system consists of a network of tracheae. The tracheae open through 10 pairs of small holes, called spiracles. The spiracles are present on the lateral side of the body. There are 2 pairs of spiracles in thorax and 8 pairs in abdomen. Tracheal tubes are subdivided into tracheoles. They carry oxygen to all the parts. The opening of the spiracles is regulated by sphincters. Exchange of gases takes place by diffusion.

    Excretory System

    Malpighian tubules are the excretory organs. Each tubule is lined by glandular and ciliated cells. They absorb nitrogenous wastes and convert them into uric acid. Uric acid is excreted out through the hindgut. Additionally, fat body, nephrocytes and urecose glands also help in excretion.

    Nervous System

    The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia. The ganglia are joined by paired longitudinal connectives on the ventral side. Three ganglia lie in the thorax and six in the abdomen. The nervous system in cockroach is spread throughout the body. In the head region, the brain is represented by supra-oesophageal ganglion. It supplies nerves to antennae and compound eyes.

    Sense Organs: Antennae, eyes, maxillary palps, labial palps, anal cerci, etc. are the sense organs in cockroach. The compound eyes are situated at the dorsal surface of head. Each eye consists of about 2000 hexagonal ommatidia. Presence of several ommatidia gives mosaic vision to the cockroach. This gives more sensitivity but less resolution. This type of vision is common during night.

    Reproductive System:

    Cockroaches are dioecious, which means sexes are separate.

    Male Reproductive System

    male reproductive system of cockroach

    Female Reproductive System

    female reproductive system of cockroach


    Sperms are transferred through spermatophores. The fertilized eggs are encased in capsules, called ootheca.

    An ootheca is a dark reddish to blackish brown capsule. It is about 8 mm long. The oothecae are dropped or glued to a suitable surface, usually at a place with high relative humidity or near a food source.

    On an average, 9 – 10 ootehcae are produced by a female. Each ootheca contains 14 – 16 eggs.

    Indirect Development

    Development is indirect and is paurometabolous. Development through nymph stage is called paurometabolous. The nymph resembles the adults. The nymph grows by moulting about 13 times to reach the adult form. Wing pads are seen in the penultimate stage of development but wings are present only in adults.

    Significance for Human

    Most of the species are wild and have no economic importance. Some species live in and around human habitat. They destroy food and contaminate food with their excreta. Many bacterial diseases can be transmitted by food contamination by cockroaches.