Cockroach(1)

Question 1

give the taxonomy of a cockroach

Answer 1

Phylum- Arthropoda (jointed appendages and and chitinous skeleton)
Class - Insecta (3 pairs of jointed legs)
Order- Dictyoptera
Genus- Periplaneta
Species- americana

Question 2

explain some features about cockroach

Answer 2

Cockroach is omnivorous, cursorial (fast runner) and
nocturnal animal. It also exhibits Cannabalism.

Parental Care does not found in Cockroach.

Cockroach chromosome no. = 34.

Question 3

how are the three segments of coackroach divided

Answer 3

Body of cockroach is divided in to 3 parts called →Tegmata. They are-
HEAD, THORAX AND ABDOMEN.

In Embryo stage head (6) + thorax (3) + abdomen(11) = 20 segments
In Adult stage head (1) + thorax (3) + abdomen(10) =14 segments

Sclerites of head fused fully to form head capsule (formed by the
fusion 6 segments).

Question 4

name of different chitinous plates

Answer 4

Exoskeleton of chitin plates occurred in each segment. Chitin plates called
“sclerites”.

Sclerites of dorsal side - tergum or tergite.
Sclerites of ventral side - sternum or sternite.
Sclerites of lateral side - pleurons or pleurites.

Sclerites joined each other by “membrane” called “articular or arthrodial
membrane.”

Question 5

explain the mouth parts of the cockroach

Answer 5

A cavity formed due to presence of mouth parts called pre-oral
cavity. 5 types of mouth parts-

Labrum or Upper Lip - Dorsally overhangs the mouth. Holds the
food for feeding & has gustato-receptor (tasting).

2. Mandibles or Jaw (1-pair) - They form the lateral wall of pre-oral
   cavity. Grinding of food.
3. First maxillae (1-pair) - Putting the food in oral cavity. Also used
   as brush to clean antenna and wings.
4. Second Maxillae or Labium or lower lip - It forms the floor of
   pre-oral cavity and covers ventral side.
5. Hypopharynx or lingua or tongue - Non-chitinous flexible
   structure. Common salivary duct opens at the base.

Question 6

where are the legs present and what are their parts?

Answer 6

5 segments are present in legs known as Podomeres

(i) coxa
(ii) trochanter
(iii) femur
(iv)tibia
(v) tarsus
(vi) pretarsus
(vii) claw

Question 7

what are th 2 types of wings

Answer 7

Forewing or Mesothoracic
wing or Elytra or Tegmina-
long, narrow, thick, leathery,
dark, opaque, covers body.

Hindwing or Metathoracic
wings- small, broad, thin,
membranous, transparent,
helpful in flight

Question 8

what are the abdomen

Answer 8

10 segments are present in male and female.

10th tergum bowl shaped and bifurcated and has 1 pair
”Anal cerci - Sound receptor” bear in both male and
female.

7th tergum is largest in male and female and covers 8th
and 9th tergites.

Stink gland present in between 5th and 6th tergum its
smell repels enemies.

Sternum : In male- 9 sternum and in female- 7 sternum.

Anal or caudal style – 1 pair from 9th sternum only in male,
non segmented structures → Help in copulation.

Question 9

what is haemocoel

Answer 9

Also known as Haemocoel

Haemocoel is not true coelom

All arthopodes are true coelomates but coelom is highly
reduced and found only in the form of the cavity of gonads
called Gonocoel.

Lagre fat bodies (corpora adiposa) present in haemocoel

Fat bodies are analogous to liver of higher animals

Question 10

what are the salivary glands

Answer 10

Consists of salivary glands and alimentary canal
Salivary glands secretes → Saliva
which contain amylase, cellulase,
chitinase.

It is attached to crop

Question 11

3 parts of the alimentary canal

Answer 11

A) FOREGUT-Ectodermal in origin- cuticle layer present
B) MIDGUT-Endodermal in origin- cuticle layer absent
C) HINDGUT-Ectodermal in origin- cuticle layer present

Question 12

foregut parts:

Answer 12

(i)- gizzard: helps in grinding of food with cuticular teeth/ cavity is called armarium

(ii) sieve platE: filtering of food due to cuticular hair

(iii)stomodeal valve: prevent backflow of blood/ junction of fore and midgut

foregut is formed by invagination of body wall. the cuticle is present in the inner wall/

Question 13

midgut or mesenteron parts:

Answer 13

(i) Anterior top part: cardia- secrete peritropic memebrane m/o glyocgen and protein beacsue midgut do not have cuticle layer

stomodeoal valve opens onto cardia into the midgut

bacetria and symbiotic protozoa present whichhelp in the digestion

mesenteron is muscular

Hepatic caeca is derives from mesenteron

Question 14

hind gut parts

Answer 14

(a) 100-150 yellow colored thin tubules attached at the junction of
hind gut and mid gut called “Malpighian tubules” → Removal
of excretory products from haemolymph)

(b) Hind gut has three parts :
(i) Ileum - Its wall is thin and internally folded. Its cuticle bears
minute spines, which serve to break the peritrophic
membrane.
(ii) Colon - Longest and broader part
(iii) Rectum - Last part, oval shaped. Its wall has 6 folds - called
Rectal papillae which absorb water.

Anus - At the end of 10th abdominal segment.

Question 15

wat are some other excretory structure except malphigiain tubules

Answer 15

Urate cell : Storage excretion

Nephrocytes and fat bodies: Storage excretion

Body wall : Absorbs excretory materials from Haemocoel and store in
cuticle. Then at the time of moulting excretory substances and cuticle
separate out from body

Uricose glands : These help in excretion in male cockroach.

Question 16

whereare the spiracles are present

Answer 16

(d) 10- pair spiracles, 2-pairs on thorax and 8-pairs on
abdomen.
(e) 1st thoracic and 1st abdominal spiracle - Always open
f) All spiracles :- on “Pleurone” (Lateral side of body)

Question 17

what does blood do

Answer 17

Open type or Lacunar type
(i) Colourless plasma
(ii) WBC (Haematocytes)
BLOOD VASCULAR SYSTEM
Blood vessel are poorly developed and open into
space called – HAEMOCOEL
Phagocytosis of bacteria
Related with blood clotting
In BLOOD → RBC, Haemoglobin ABSENT
BLOOD works as HYDRAULIC SKELETON

BLOOD is not related with respiration because respiratory pigment
absent
BLOOD helps in the transportation of nutrients, hormones and
excretory wastes

Blood contains trehalose sugar disaccaride.

Question 18

what are the 2 diaphragms in cockroach

Answer 18

Two horizontal septa/diaphragm divides haemocoel in to
3 chambers. These septa are -
1-Dorsal diaphragm2-Ventral diaphragm
These have pores called “fenestrae”

Diaphragms divides the HAEMOCOEL in to three chambers :
Peri cardial sinus (DORSAL) : has heart chambers
Perivisceral sinus (MIDDLE) : has alimentary canal and fat body.
Perineural sinus (VENTRAL) :has nerve cord.

Question 19

how is the flow of blood between the sinuses

Answer 19

first the blood is pumped from the anterior aorta into the head sinus from where it goes to the perineural sinus(ventral) then it moves to perivisceral sinus and then it moves to pericardial sinus where it goes into the heart through ostia.

Question 20

explain heart of cockroac

Answer 20

(a) Heart is divided into 13 inverted funnel like chambers
.
(b) First chamber of heart in the form of long tubule called “anterior
aorta” It opens into head sinus

(c) Each chamber connected with Pericardial sinus by 1-pair of pores,
called “Ostia”. These pores act as valve.
(d) Blood enters from Pericadial Sinus to heart through Ostia.
(e) Each posterior chamber of heart connected/related with anterior
chamber by a valve like pore.
(f) These pore help in flow of blood from posterior to anterior part.

the heart is neurogenic( under nervous control)

theheart chambers are connected by 12 fan shaped alary muscles. when they contract, the diaphragms flatten, bp dicreases casuing blood to enter heart

Question 21

what are nephrocytes

Answer 21

Special type of cells attached with heart wall called “Nephrocytes-
Storage excretion in the form of “Uric acid”.

Question 22

what are the 3 types of galglion

Answer 22

supraoesophageal ganglion amd sub oseophageal ganglion RE CONNECTED BY CIRCUM OESEOPHAGEal connectives to form nerve ring.

there 3 ganglion in thorax and 6 ganglion in the tb

Question 23

wha are the sense organs

Answer 23

Antennae → Tactile receptors, Olfactory receptors, detect
vibrations.

*Compound eyes → Each compound eye is made up of 2000
units called Ommatidia.
*Mosaic Vision or Apposition vision has more sensitivity but less
resolution.

*Simple eye or Ocelli → Photoreceptor (to detect light), No image
formation.

Maxillary and Labial Palps → Tactile receptors and Gustato
receptors
*Anal Cerci → Sound receptors( antennae also detect sound)
*Legs → Gustato-receptors

Question 24

male repro system

Answer 24

(
(a) 1-pair of testis in “4-6” abdominal segment. Each testis formed
of “3 or 4 lobes” each lobe divided into many lobules

(b) Vasa deferentia - A vasa deferens arises from each testis these
open in an ejaculatory duct.

c) Ejaculatory duct opens outside by male genital pore. Seminal
vesicle in form of vesicles located upon ejaculatory duct.

(d) Spermatogenesis→ Completely in testis.

(e) Seminal vesicle :- Stored the sperms. All sperms glue together’s
to form a ball called “sperm ball”.
(f) A gland associated with seminal vesicles called Mushroom gland
or Utricular gland is present in the 6th - 7th abdominal segment
as an accessory reproductive gland.
Having two types of tubules-
Small tubules on inner side - Utriculi brevivores → Nutritive fluid in
spermatophore.
Long tubules outside - Utriculi majores → Secrete a membrane
around sperm ball. Tips of long tubules called “Uricose gland” →
These absorb excretory material from haemocoel.

(g) Ejaculatory duct secrete another coat on spermatophore.
spermatophore - ”Double layered.”

(h) A gland located on mushroom gland called phallic gland or
congloblate gland. It opens out side by a long duct “Phallic
aperture”.

When they go out side from male genital pore then phallic gland
secretes another layer, so spermatophore becomes three layered.

(j) Chitinous structures associated with phallic aperture and male
genital pore called “Phallomeres” or “Gonapophysis”.
Phallomeres
(1) Left phallomere
(2) Right phallomere
(3) Ventral phallomere

Question 25

function fo diff parts of female repro system

Answer 25

→ Function of Ovary & Ovarioles- Formation of Ova
→ Function of Oviduct -Transport of Ova
→ Function of Spermatheca- Storage of sperms after Copulation
→ Function of Right & Left Collaterial Gland - Formation of Ootheca

Function of Ovipositor processes– Arrange ova in rows

Question 26

female reproductive system

Answer 26

(a) 1-pair of ovary situated in “2nd to 6th segment of abdomen”.
**(b) Each ovary is made up of 8-long tubules called “Ovarioles.” Only
one egg from in each ovariole. It means 16 ova are matured at a
time in cockroach. Both oviduct of ovaries fuse and form
“vagina”. **
(c) Vagina - Vagina opens inside body in a genital chamber.
(d) Genital chamber- formation of genital chamber by the fusion of 3
abdominal sternum
(e) 7th sternum - Forms the floor of genital chamber.
(f) 8th and 9th sternum - become telescoped inwards to form the roof
and sides of this pouch, the pouch itself is divisible into a genital
chamber in front and oothecal chamber behind.
(g) A pair of “Spermatheca” present in 6th segment associated with
genital chamber. Spermatheca unequal in size.
(h) Both spermatheca open by a pore in genital chamber.
(i) 1-pair of collaterial glands associated with genital chamber. These
are branched tubular glands.
Left collaterial gland = more branched

Question 27

explation the copulation process

Answer 27

COPULATION
(a) “Breeding season:- from march to september.
The females secrete a highly odorous and volatile “sex attracting
scent from their scent glands called pheromones or ectohormones.

(b) Male perceive the smell of this scent with the help of olfactory
sensillae located upon their antennae.
(c) Copulation time = One hour

Question 28

explain the formation of ootheca

Answer 28

(b) After fertilization the left collaterial gland secretes a
soluble “milky protein” while the right one secrete
dihydroxyphenol. Both secretions mix to form a brownish
scleroprotein.

(c) Sclero protein forms a common egg case, called ootheca.
Ootheca is a dark reddish to blackish brown capsule, about
3/8” (8 mm) long.

(d) Development is Paurometabolous (through Nymphal
stages)
(c) Development time - “4 to 8” weeks.
(e) Juvenile stage inside ootheca is called “nymph“.
Nymph appears like adult.
Development :-
(f) The Nymphs look very much like adults, the nymphs grows
by moulting about 13 – times to reach the adult form.
(g) it is smaller than adults and also lacks mature reproductive organs

Question 29

What are gonapophyses in female cockroaches

Answer 29

They are structures present outside near the female gonopore. They help hold the male during copulation. They help in laying eggs

Question 30

What is vestibulum and genital chamber

Answer 30

Vestibulum is the entry part of the genital pouch it serves as the area where the sperms are deposited.

Genital chamber is present further into the genital pouch. it is the place where fertilization happens. the Collateral gland, spermatheca and oviduct open into this place.

Vestibulum and the genital chamber form the genital pouch

Question 31

2 most common Indian cockroaches

Answer 31

Periplaneta americana
Blatta orientalis

Question 32

What is the function of wings

Answer 32

Protecting against predator
Blatta orientalis has less developed wings

Question 33

Apposition vision is formed in

Answer 33

Bright light