The reproductive systems of insects are similar to those of vertebrates, with both male and female gametes being haploid and unicellular. Most insect species reproduce sexually through internal fertilization. The male reproductive system produces and stores sperm in the testes and seminal vesicles before delivering it to the female through the aedeagus. The female system produces eggs in the ovaries which develop and move into the common oviduct for fertilization and laying. Accessory glands support these processes by providing fluids and forming the eggshell. Fertilization occurs when sperm fuses with the egg nucleus, and the fertilized egg then undergoes embryonic development.

1. Reproductive System in Insects.
AEN 201 Fundamentals Of Entomology.
Course Mentor: Dr Pretheep Kumar
Expounded by:
Chandini S
2013-009-005
II B.Sc.(Sericulture)

2. &The reproductive organs of insects are similar in
structure and function to those of vertebrates.
&Both types of gametes are haploid and unicellular,
but eggs are usually much larger in volume than
sperm.
&Most insect species reproduce sexually by internal
fertilization.

3. Functions of the Reproductive
System:
Male:
&Production of sperm.
&Storage of sperm.
&Delivery of sperms to the
female.
Female:
&Production of eggs, including yolk
and chorion formation.
&Reception and storage of sperm
(may be for long times).
&Coordination of events that lead to
fertilization and oviposition.

4. Male Reproductive System:
&Testes - Usually near the back of the abdomen.
&Each testes is subdivide into functional units - Follicles - sperm
is produced.
&At the distal end of each follicle-group of germ cells -
Spermatogonia.
&Spermatogonia - divide by mitosis - Increase in size to form
Spermatocytes.

5. &Spermatocytes - migrate toward the basal end of the follicle.
&Spermatocytes – undergo meiosis – yields 4 haploid spermatids.
&Spermatids – develop into mature spermatozoa.
&One or more pair of accessory glands – usually associated with
male’s reproductive system.
&2 major functions of accessory glands:
Manufacture of seminal fluid.
Production of spermatophores.

6. &Mature sperm pass out of the testes through short
ducts – Vasa efferentia.
&Collected in storage chambers – Seminal vesicles.
&Similar ducts – Vasa deferentia – from the seminal
vesicles – join together near the body mid line –
form a single Ejaculatory duct – leads out of the
body through copulatory organ – Aedeagus.

8. Female Reproductive System:
&A pair of ovaries.
&Each ovary - subdivided into functional units – Ovarioles –
Eggs are produced.
&Near the distal end of each ovariole – group of germ cells –
Oogonia – divide by Mitosis.
&Oogonia – increase in size to form Oocytes.
&Each oocyte – undergoes Meiosis – yields 4 cells – 1 egg and 3
polar bodies.

9. &Polar bodies may disintegrate or they may accompany the egg as nurse
cells.
&Developing eggs move down the ovariole – grow in size by absorbing
yolk.
&Mature eggs leave the ovaries through short Lateral Oviducts.
&Near the body midline – lateral oviducts join to form a common oviduct
– opens into a genital chamber – Bursa Copultrix.
&Female accessory glands – supply lubricants for the reproductive system
and screte a protein-rich egg shell – Chorion.
&Accessory glands – usually connected by small ducts to the common
oviduct – Bursa Copultrix.

11. Processes:
&Copulation – The male deposits its spermatophore in the bursa
copultrix.
&Peristaltic contractions force the spermatophore into the female’s
spermatheca.
&Spermathecal gland – Produces enzymes and nutrients.
&Ovulation – Each egg passes across the opening to the
spermatheca – stimulates release of a few sperm onto the egg’s
surface.

12. &Fertilization – Occurs as soon as one sperm’s
nucleus fuses with the egg cell’s nucleus.
&Oviposition – Egg laying – usually follows closely
after fertilization.
&After the completion of all the processes – the egg
is ready to begin embryonic development.

13. Oviparity:
&Egg laid shortly after
fertilization.
&No retention
&No nutrients to embryo
after fertilization.
&Eggs retained.
&Embryo fed by mother.
&Immature may
complete development
before deposition.
Viviparity:

14. Types of Reproduction:
& Paedogenesis – Reproduction by larval insects.
& Parthenogenesis – Developments without fertilization –
Unfertilized eggs produce – Males, Female, Or Both.
& Polyembryony .
Mating:
& Females of some species – essentially Monogamous – mate only
once.
& Most female insects – Polygamous - mate several to many times.

15. CITATION:
“The Reproductive System of Insects”
Dr Arwa Elaagip,
Department of Parasitology and Medical
Entomology,
University of Kartoum.

16. Thankieyeww