Reproductive System: Cockroach | Additional Study Material for NEET PDF Download

REPRODUCTIVE SYSTEM

Cockroach - "Unisexual"

Male reproduction system:-

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

(b) Vasa deferentia - A vasa deferense 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) A gland associated with seminal vesicles called mushroom gland or utricular gland having two types of tubules, small tubules on inner side- utriculi brevivores.

Large tubules outside - utriculi majors

Tips of long tubules called "Uricose gland"

These absorb excretory material from haemocoel.

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

(f) Chitinous structures associated with phallic aperture and male genital pore called "phellomeres" or gonapophysis."

(a) Phallic aperture present on left phellomeres

(b) Male genital pore situated on Ventral phellomeres.

(1) Left phellomeres :-

(1) made up of a flat chitinous plate

(2) four types of lobes attached with it

- lower most lobe titilator, with a hooks on tips

- "Pseudopenis" - long with bulbow apex

- aspirate lobe - lobe of spiny surface, phallic duct opens at the base of asperate lobe

Innermost lobe - "Acutolobe - with a hook

(2) "Right phellomeres" It is a chitinous structure.

Two large hooks present at apex and a hook present on base of right phellomeres.

"Ventral - phellomeres"

(a) simplest and formed of a flat chitinous plate hooks absent. Hooks help in opening of oothecapore of female.

Phellomeres :- "External genital organ"

(a) "Spermatogenesis" "Completely in testis"

(b) Seminal vesicle :- Stored the sperms

(c) All sperms glue together's to form a ball called "sperm ball"

(d) long tubules secrete a membrane around sperm ball called spermatophore

(e) small tubules :- secrete a nutritive fluid in spermatophore.

(f) at the time of copulation spermatophore enters in to ejaculatory duct.

(g) Ejaculaotry duct secrete another coat on spermatophore. spermatophore - "double layered."

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

Female reproductive system

(1) 1-pair of ovary situated in "2nd to 6th segment of abdomen".

(2) 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"

(3) Vagina - vagina opens inside body in a genital chamber.

(4) Genital chamber - formation of genital chamber by  the fusion of 3 abdominal sternum,

(5) 7th sternum - forms the floor of genital chamber.

(6) 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.

(7) A pair of "Spermatheca" associated with genital chamber. 

Spermatheca unequal in size

(8) both spermatheca open by a pore in genital chamber.

(9) A plateform in genital chamber just beneath spermathecapore called "spermatheca Papilla:

(10) 1-pair of collaterial glands associated with genital chamber. These are branched tubular gland"s. left collaterial gland = more branched

(11) Both glands open in genital chamber by a common pore

(12) Three pairs of chitinous processes hanging from the roof of genital chamber into its cavity are the external ganitalia of female cockroach . These are called ovipositor porcesses because these serve to arrange the ova in a newly formed ootheca, and possible help in giving proper shape to the oothecae.

Copulation

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

(2) male perceive the smell of this scent with the help of olfactory sensillae located upon their antennae.

(3) male cockroach opens the ootheca pore with the help of hooks.

(4) The male insert whole of its phallomeres into the females's genital pouch. then it inserts its pseudopenis into the female gonopore for firm anchorage.

(5) In this position male genital pore situated on spermathecal papilla

(6) discharge spermatophore by male genital pore upon the spermathecal papilla of female

(7) After that the secretion of its phallic gland upon the spermatophore

Copulation time 1 one hour

(1) The spermatophore remains plastered to the spermathecal papilla of female for about 20 hours. during this period all its sperms escape out and fill in the two spermathecae of the female, then the female drops out the case of empty spermatophore.

(2) Sixteen ova, one from each ovariole of the two ovaries, are dischagred at a time into the genital pouch where these are arranged by the gonapophyses into two parallel row.

(3) Simultaneously, sperms stored in the spermathecae are also discharged into the genital pouch to fertilize the ova.

Fertilization

(a) "Internal fertilization"

(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.

(d) formation time - 24 hours

(e) one end of ootheca like a saw and these close the mouth of ootheca

(f) the female deposit it in some dark and dry places.

Development :-
(a) 1 - female form 15-40 ootheca in life time.

(b) Development of egg inside ootheca

(c) Ootheca are adaptation of terrestrial life to prevent the "Water lose"

(d) Development time - "4 to 8" weeks

(e) juvenile stage inside ootheca is called "nymph"

Nymph appear like adult except for wings and reproductive organs

(f) Nymph changes into an adult in - 1 year

(g) During metamorphosis - 7 to 12 times moulting (average - 10 times moulting)

(h) time interval between two moulting called "stadium. 6-11 stadium.

(i) In between moulting nymph called "instar"

Adult insect are called imego"

Metamorphosis

"Incomplete or paurometabolus"

In insect, those have larva stage have complete or holometabolous metamorphosis.

- "Cleavage" = "superficial meroblastic".

- Gastrulation - "Poly invagination" or "Ingression"

- egg - "megalecithal" and "centrolecithal"