Morphology of Cockroach

COCKROACH

  • Cockroaches are insects belonging to the class Insecta within the Phylum Arthropoda.
  • They typically have brown or black bodies, although bright yellow, red, and green-colored cockroaches have been reported in tropical regions.
  • Their size can range from ¼ inches to 3 inches (0.6-7.6 cm), and they are characterized by long antennae, legs, and a flat extension of the upper body wall that conceals their head.
  • Cockroaches are nocturnal omnivores, meaning they are active at night and consume a wide variety of food types. They are found in damp places and are distributed worldwide.
  • In human habitats, they have become residents, and as a result, they are considered serious pests and can act as vectors for several diseases.
  • While many species of cockroaches are wild and of little economic significance, a few species have adapted to living in and around human habitats.
  • These specific cockroach species are considered pests due to their ability to cause problems in human living spaces.
  • One of the key issues with cockroaches is their tendency to damage and contaminate food sources. They can destroy food and introduce contamination through their smelly excreta.
  • Additionally, cockroaches pose a health risk as they can transmit various bacterial diseases by contaminating food materials with pathogens, making them a potential source of foodborne illnesses. 

Morphology of Cockroach

  • Adult common cockroaches, like Periplaneta americana, have a size ranging from 34 to 53 mm. Male cockroaches of this species possess wings that extend beyond the tip of their abdomen.
  • The body of a cockroach is segmented into three main regions: head, thorax, and abdomen. The entire body is covered by a hard chitinous exoskeleton, typically brown in color.
  • Each body segment features hardened plates known as sclerites, with tergites dorsally and sternites ventrally, connected by thin and flexible articular membranes, known as arthrodial membranes.
  • The head is triangular and located anteriorly at right angles to the body's longitudinal axis. It is formed by the fusion of six segments and exhibits great mobility in all directions due to its flexible neck.
  • The head capsule contains a pair of compound eyes, and a pair of thread-like antennae arises from membranous sockets in front of the eyes. These antennae have sensory receptors that help in monitoring the environment.
  • The mouthparts are adapted for biting and chewing and consist of a labrum (upper lip), a pair of mandibles, a pair of maxillae, and a labium (lower lip). A median flexible lobe, acting as a tongue (hypopharynx), is present within the cavity enclosed by the mouthparts.

 

  • The thorax is divided into three parts: prothorax, mesothorax, and metathorax. The head connects to the thorax via a short extension of the prothorax, known as the neck. Each thoracic segment bears a pair of walking legs.
  • The cockroach has two pairs of wings, with the first pair (tegmina) arising from the mesothorax and serving as opaque dark and leathery coverings for the hind wings. The hind wings are transparent and membranous and are used for flight.
  • The abdomen of both males and females is composed of ten segments. In females, the 7th sternum, together with the 8th and 9th sterna, forms a brood or genital pouch that contains the female gonopore, spermathecal pores, and collateral glands.
  • In males, the genital pouch or chamber is located at the hind end of the abdomen and is bounded dorsally by the 9th and 10th terga and ventrally by the 9th sternum. It contains the dorsal anus, ventral male genital pore, and gonapophysis.
  • Males are equipped with a pair of short, thread-like anal styles, which are absent in females. In both sexes, the 10th segment bears a pair of jointed filamentous structures known as anal cerci.