COCKROACH 2

Question 1

What are the three regions of the alimentary canal?

Answer 1

Foregut, midgut, and hindgut.

Question 2

What does the mouth open into?

Answer 2

A short tubular pharynx.

Question 3

What is the function of the oesophagus?

Answer 3

It serves as a narrow tubular passage leading to the crop.

Question 4

What is the function of the crop?

Answer 4

It stores food.

Question 5

What follows the crop in the alimentary canal?

Answer 5

The gizzard or proventriculus.

Question 6

What is the structure of the gizzard?

Answer 6

It has an outer layer of thick circular muscles and a thick inner cuticle with six highly chitinous plates called teeth.

Question 7

What is the function of the gizzard?

Answer 7

It helps in grinding food particles.

Question 8

What lines the entire foregut?

Answer 8

Cuticle.

Question 9

What are hepatic or gastric caecae?

Answer 9

A ring of 6-8 blind tubules present at the junction of the foregut and midgut that secrete digestive juice.

Question 10

What is present at the junction of the midgut and hindgut?

Answer 10

A ring of 100-150 yellow-colored thin filamentous Malpighian tubules.

Question 11

What is the function of Malpighian tubules?

Answer 11

They help in removing excretory products from haemolymph.

Question 12

How does the hindgut compare to the midgut?

Answer 12

The hindgut is broader than the midgut.

Question 13

What are the three parts of the hindgut?

Answer 13

Ileum, colon, and rectum.

Question 14

Where does the rectum open out?

Answer 14

Through the anus.

Question 15

What type of blood vascular system does a cockroach have?

Answer 15

Open type.

Question 16

How are the blood vessels in a cockroach?

Answer 16

Poorly developed and open into space (haemocoel).

Question 17

Where are the visceral organs of a cockroach located?

Answer 17

In the haemocoel, bathed in blood (haemolymph).

Question 18

What is the composition of haemolymph in a cockroach?

Answer 18

Colourless plasma and haemocytes.

Question 19

What is the structure of the cockroach’s heart?

Answer 19

An elongated muscular tube lying along the mid-dorsal line of the thorax and abdomen.

Question 20

How is the heart of a cockroach differentiated?

Answer 20

Into funnel-shaped chambers with ostia on either side.

Question 21

How does blood circulate in the cockroach’s body?

Answer 21

Blood enters the heart through ostia from the sinuses and is pumped anteriorly to sinuses again.

Question 22

What does the respiratory system of a cockroach consist of?

Answer 22

A network of trachea that open through 10 pairs of spiracles on the lateral side of the body.

Question 23

What is the function of tracheal tubes and tracheoles?

Answer 23

They carry oxygen from the air to all parts of the body.

Question 24

How is the opening of spiracles regulated?

Answer 24

By sphincters.

Question 25

Where does gas exchange take place in the cockroach?

Answer 25

At the tracheoles by diffusion.

Question 26

What is the primary excretory organ in a cockroach?

Answer 26

Malpighian tubules.

Question 27

What type of cells line the Malpighian tubules?

Answer 27

Glandular and ciliated cells.

Question 28

How do Malpighian tubules function in excretion?

Answer 28

They absorb nitrogenous waste and convert it into uric acid, which is excreted through the hindgut.

Question 29

Why is a cockroach called uricotelic?

Answer 29

Because it excretes nitrogenous waste in the form of uric acid.

Question 30

What other structures help in excretion besides Malpighian tubules?

Answer 30

Fat body, nephrocytes, and urecose glands.

Question 31

What does the nervous system of a cockroach consist of?

Answer 31

A series of fused, segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side.

Question 32

How many ganglia are present in the thorax and abdomen of a cockroach?

Answer 32

Three ganglia lie in the thorax, and six in the abdomen.

Question 33

Where is the majority of the cockroach’s nervous system located?

Answer 33

It is spread throughout the body, with most of it situated along the ventral (belly-side) part.

Question 34

What happens if the head of a cockroach is cut off?

Answer 34

It can still live for up to one week.

Question 35

What is the brain of a cockroach represented by?

Answer 35

The supra-oesophageal ganglion, which supplies nerves to the antennae and compound eyes.

Question 36

Name some sense organs of a cockroach.

Answer 36

Antennae, eyes, maxillary palps, labial palps, anal cerci, etc.

Question 37

Where are the compound eyes of a cockroach located?

Answer 37

On the dorsal surface of the head.

Question 38

How many ommatidia are present in each compound eye of a cockroach?

Answer 38

About 2000 hexagonal ommatidia.

Question 39

What kind of vision does a cockroach have?

Answer 39

Mosaic vision, which provides more sensitivity but less resolution.

Question 40

Why is cockroach vision called nocturnal vision?

Answer 40

Because it is more sensitive in low light and helps in night vision.

Question 41

Are cockroaches dioecious or monoecious?

Answer 41

Cockroaches are dioecious, meaning they have separate sexes with well-developed reproductive organs.

Question 42

Where are the testes located in male cockroaches?

Answer 42

A pair of testes is located on each lateral side in the 4th-6th abdominal segments.

Question 43

What is the function of the vas deferens in male cockroaches?

Answer 43

The vas deferens carries sperm from the testes and opens into the ejaculatory duct through the seminal vesicle.

Question 44

Where does the ejaculatory duct open in male cockroaches?

Answer 44

It opens into the male gonopore, which is situated ventral to the anus.

Question 45

What is the function of the mushroom-shaped gland in male cockroaches?

Answer 45

It acts as an accessory reproductive gland and is present in the 6th-7th abdominal segments.

Question 46

What are male gonapophysis (phallomeres) in cockroaches?

Answer 46

They are chitinous asymmetrical structures that surround the male gonopore and serve as external genitalia.

Question 47

What are spermatophores in cockroaches?

Answer 47

Sperms stored in the seminal vesicles are glued together into bundles called spermatophores, which are discharged during copulation.

Question 48

Where are the ovaries located in female cockroaches?

Answer 48

Two large ovaries are present laterally in the 2nd-6th abdominal segments.

Question 49

What are ovarioles in female cockroaches?

Answer 49

Each ovary consists of eight ovarian tubules (ovarioles), which contain a chain of developing ova.

Question 50

How do the oviducts function in female cockroaches?

Answer 50

The oviducts from each ovary unite into a single median oviduct (vagina), which opens into the genital chamber.

Question 51

What is the function of the spermatheca in female cockroaches?

Answer 51

A pair of spermatheca is present in the 6th abdominal segment and opens into the genital chamber, storing sperm for fertilization.

Question 52

How are sperms transferred in cockroaches?

Answer 52

Sperms are transferred through spermatophores.

Question 53

What are fertilized cockroach eggs encased in?

Answer 53

They are encased in capsules called oothecae.

Question 54

What is the appearance and size of an ootheca?

Answer 54

It is a dark reddish to blackish-brown capsule, about 8 mm (3/8 inch) long.

Question 55

Where do female cockroaches place their oothecae?

Answer 55

They are dropped or glued to a suitable surface, usually in a crack or crevice with high humidity near a food source.

Question 56

How many oothecae does a female cockroach produce on average?

Answer 56

Around 9-10 oothecae.

Question 57

How many eggs are present in each ootheca?

Answer 57

Each ootheca contains 14-16 eggs.

Question 58

What type of development does Periplaneta americana (American cockroach) undergo?

Answer 58

Paurometabolous development (incomplete metamorphosis through a nymphal stage).

Question 59

How do cockroach nymphs compare to adults?

Answer 59

Nymphs look very much like adults but lack fully developed wings.

Question 60

How do cockroach nymphs grow into adults?

Answer 60

By moulting about 13 times.

Question 61

What is a key difference between the last nymphal stage and adult cockroaches?

Answer 61

The last nymphal stage has wing pads, but only adult cockroaches have fully developed wings.