Question

Position of testis in Periplaneta americana

Answer 1

Hint: The male reproductive system of a cockroach consists of two testes. These testes lie on both the lateral sides of the abdomen. Spermatophores are the glued bundles of the sperms present in a cockroach. These spermatophores are released during copulation.

Complete answer:
Cockroaches are dioecious animals with both sexes and well developed reproductive organs.
-On the lateral sides in the 4th - 6th segment of the abdomen, the male reproductive system consists of a pair of testes. A thin vas deferens arise from each testis which opens into the ejaculatory duct through the seminal vesicle.
-The male reproductive system of cockroach includes a pair of testes, vasa deferentia, and ejaculatory duct, utricular gland, phallic gland, and the external genitalia.
-The pair of three-lobed testes are present dorsolaterally in the 4th and 5th abdominal segments embedded in the body. The testes in a young cockroach are well developed and elaborate structures and are full of sperms.
-These testes become non-functional and are reduced in old adults, but a little number of sperms can be found in them. Therefore, the position of testis in Periplaneta americana is 4th, 5th, 6th abdominal segments.

So, the correct answer is option B.

Additional Information:
A thin thread-like, white vasa deferens arises from each testis. A broad and elongated median duct known as the ejaculatory duct runs backward in the abdomen and opens out by male gonopore situated ventral to the anus.

Note: The female reproductive system of a cockroach comprises a pair of ovaries, vagina, genital pouch, colleterial glands, spermatheca, and the external genitalia. The two large, light yellow-coloured ovaries are present laterally in the segment 4th, 5th, 6th, of the abdomen embedded in the body.