Insects Mr. Jeff Peterson Fulbright Teacher from Indiana, USA
Insects • Myriapoda
Insects Difference between centipede and millipede
Insects • Insecta • Cockroach • The body is divided into head, thorax and abdomen. • The head bears a pair of antennae and a pair of compound eyes. • The antennae serves as a sensory organ. • The thorax is divided into 3 segments.
Insects • Insecta • Cockroach • Each segment has a pair of jointed legs. • Two pairs of wings are present in the thorax region. • The abdomen consist of 11 segments out of which the last segment is underdeveloped.
Insects • Complete Fig 5.9 Cockroach, page 37
Insects • Digestive System – Alimentary Canal • The mouth leads to buccal cavity (which has pair of salivary glands) • Complete Fig 5.10 page 38
Insects • Circulatory System • Cockroach has an open circulatory system. • Blood of cockroach is white in color because the red pigment is dissolved in the plasma. • A simple tube consisting of thirteen chambers present on the dorsal surface as a heart.
Insects • Respiratory System • It consist of a network of fine tubes called trachea. • Trachea branches into minute tracheoles which reach all parts of the body. • Air reaches the trachea through the minute hole found along the sides of the body of the insect.
Insects • Respiratory System
Insects • Respiratory System • These are called spiracles on stigma. • In the cockroach there are 10 pairs of stigmata, 2 on the thorax and 8 on the abdomen.
Insects • Excretory System • Excretory organs are represented by a number of finely coiled tubes called malpighian tubules. • They remove the waste material from blood and discharge into the gut.
Insects • Reproductive System • Sexes are separate. • Female has pair of ovaries called the female reproductive organ. • Male has a pair of testes which produce sperm, called the male reproductive organ.
Insects • Reproductive System • Fertilization occurs in the oviduct. • Embryo formed releases nymph. Which after several molting, forms adult.
Insects • Ootheca • The egg case of the cockroach is called ootheca. • It has 16 eggs arranged in 2 rows.
Insects • Nymph • The young one of the cockroach is called nymph. • It resembles an adult except in size and color. • It is pale in color with large eyes, molts several times to become an adult.