Describe the external characters of cockroach. What is the importance of the exoskeleton of this insect?
- Cockroaches are brown or black bodied animals with their size ranging from ¼ inches to 3 inches (0.6-7.6 cm) and having a long antenna, legs and flat extension of the upper body wall that conceals head.
- Their body is segmented and divisible into three distinct regions - head, thorax and abdomen.
- The entire body is covered by a hard chitinous exoskeleton (brown in colour).
- In each segment, exoskeleton has hardened plates called sclerites (tergites dorsally and sternites ventrally) that are joined to each other by a thin and flexible articular membrane (arthrodial membrane).
- Each thoracic segment bears a pair of walking legs.
- The first pair of wings arises from mesothorax and the second pair from metathorax.
Exoskeleton is of utmost importance to cockroach as it serves as a great defense against predators; it helps to support the body and keeps it from getting wet or drying out. It also protects it's soft, internal organs and muscles from injury.