Reproductive System of Cockroach - Male

i. In cockroach, sexes are separate, so dioecious.

ii. Testes of cockroach are located in the abdominal segments 4, 5 and 6.

iii. Mushroom gland consists of two types of tubules, (a) the long slender tubules the utriculi

majores of peripheral tubules and (b) short tubules, the utriculi breviores, making up of

the major part of the gland.

iv. Small seminal vesicles are also found associated with mushroom gland.

v. All sperms of a seminal vesicle are glued together into a large bundle called spermatophore.

vi. Spermatophore has three layered wall : inner layer secreted by utriculi majores; middle layer

secreted by ejaculatory duct and outer layer secreted by phallic gland or conglobate

gland.

vii. There are three asymmetrical chitinous structures called male ganopophytes or phallomeres.

Right phellomere, left phallomere (largest) and ventral phellomere (smallest)

i. Female organ consist of ovaries, oviduct, vagina, genital chamber, spermathecae, colleterial glands and female ganopophysis (ovipositor processes).

ii. Ovaries of cockroach are located in the abdominal segments 2 to 6. Each ovary consists of eight ovarioles.

iii. Two oviducts from each side open into a common oviduct or vagina which open into genutal chamber.

iv. A pair of collaterial glands also open in genital chamber.

v. Genital pouch or gynatrium is divisible into a genital chamber in front and oothecal chamber behind.

vi. Female genitalia consists of 3 pairs of chitinous processes hanging from the roof of oothecal chamber into its cavity.

vii. Ootheca of cockroach contains sixteen fertilized eggs. Ootheca of cockroach is formed of a protein secreted by colleterial glands.

viii. Nymph of cockroach emerge out from ootheca. A nymph resembles to adult in general structure but lacks the wings and mature reproductive organs.

ix. Instar a large stage in the development of insects (larval instar, nymphal instar). Period between two moults in insects is termed stadium.

x. In periplaneta americana the nymph grows by moulting about 13 times to reach the adult from blatta orientalis moults 6 times

xi. Metamorphosis is regulated by two hormones, ecdysone secreted by prothoracic

glands and juvenile hormone secreted by corpora allata.

Comparison of Periplaneta and Blatta

Pariplaneta americana Blatta orientalis

1. Size - larger 

2. Colour - shiny brown

3. Wings - well developed

4. Pronotum - narrower

5. Saliva without invertase

1. Size - Smaller

2. Colour - Dark brown

3. Wings - In female, the tegmina are very short:

hind wings absent

4. Pronotum - broader

6. Chromosome number:

Male 2n = 33

Female 2n = 34

5. Saliva with invertase

6. Chromosome number:

Male 2n = 47

Female 2n = 48