REPRODUCTIVE SYSTEM IN INSECTS Sexual dimorphism is noticed in cockroach In male cockroach, at the posterior end of the abdomen there is a pair of short segmented anal cerci and unsegmented anal styli. In female cerci alone are present and styli are absent.

Male Reproductive System It is located in the posterior part of the abdomen. A pair of testes is embedded in the fat bodies below the terga of fifth and sixth abdominal segments. Each testis is composed of three globular follicles lying one behind the other.

From each testis, a lateral duct called vas deferens arises which leads to the seminal vesicles. The two seminal vesicles lie side by side and bear at their anterior ends many finger- shaped diverticula. The presence of these diverticula gives the appearance of a mushroom.

So the seminal vesicles and the diverticula are together called mushroom shaped gland. It secretes the seminal fluid. It also stores the sperms after degeneration of testicular follicles. Both the vasa deferentia unite to form the ejaculatory duct which opens out through the male gonopore.

Male gonopore is surrounded by chitinous plates called gonapophyses which aid in copulation. Lying below the mushroom shaped gland is conglobate gland of uncertain function.

Female Reproductive System It is located in the posterior part of the abdomen, There is a pair of ovaries. They are laterally located. Each ovary consists of eight ovarioles or egg tubes. Each ovariole consists of vitellarium (posterior part), germarium (anterior part), and terminal filament (tapering distal end).

All the eight terminal filaments on one side unite to form a suspensory ligament which is attached to the dorsal diaphragm. From the base of each ovary arises a short duct called lateral oviduct. The two lateral oviducts unite to form a common oviduct, which opens out, through the female gonopore vulva through vagina.

A pair of spermathe­cae opens by a median aperture into the genital pouch above the vulva. Of the two one is sac like and the other is filamentous. Sperms received during copulation are stored in spermatheca.

Opening into the genital pouch are a pair of extensively branched, fibrous glands called colleteral glands. Of the two glands, left is much larger than right and lies above it. They produce the materials required for the formation of oothecae and of cementing the oothecae to substratum.

Between the vulva and the anus are chitinous processes called gonapophyses for laying of the eggs.