REPRODUCTIVE SYSTEM ;STRUCTURE OF MALE AND FEMALE REPRODUCTIVE SYSTEM IN INSECTS SPERMATOGENESIS AND OOGENESIS

1. DR HARI SINGH GOUR UNIVERSITY
SAGAR M.P.
TOPIC : SPERMATOGENESIS AND OOGENESIS
DEPARTMENT OF ZOOLOGY
INESCT MORPHOLOGY AND PHYSIOLOGY :ZOO-DSM-321 B
SUBMITTED TO :
PROF. VERSHA SHARMA
SUBMITTEDBY :
JYOTI SINGH(Y22265011)
KM. KAUSHIKI(Y22265013)
M.SC.III SEM
(ENTOMOLOGY)

2. CONTENT
INTRODUCTION
1
FEMALE REPRODUCTIVE
SYSTEM
2
OOGENESIS
3
MALE REPRODUCTIVE
SYSTEM
4
SPERMATOGENESIS
5

3. SPERMATOGENESIS
AND
OOGENESIS

4. INTRODUCTION
 INSECTSVARYGREATLYINTHEIRREPRODUCTIVEANATOMY,
BEHAVIORANDPHYSIOLOGY.
 ININSECTSMALEANDFEMALESEXESAREMOSTLYSEPARATE.
SEXUALDIMORPHISMISCOMMONWHERETHEMALEDIFFER
FROMTHEFEMALEMORPHOLOGICALLY.E.G.BEE,MOSQUITO
ANDCOCKROACH.
 THEOTHERTYPESAREGYNANDROMORPH:(SEXUALMOSAIC)
ABNORMALINDIVIDUALWITHSECONDARYSEXUAL
CHARACTERSOFBOTHMALEANDFEMALE.E.G.MUTANT
DROSOPHILA
 HERMAPHRODITE:MALEANDFEMALEGONADSAREINONE
ORGANISM.E.G.COTTONYCUSHIONSCALE

6. FUNCTION OF THE REPRODUCTIVE SYSTEM
1.Continuation ofthespecies
2. Productionofgametes
3. Productionofeggs
4.Fertilization oftheeggs
5.Layingthe eggs
6.Development ofthe embryo
Z

7. FEMALEREPRODUCTIVESYSTEM
Themainfunctionof thefemale reproductive system areegg productionandstorage ofmale's
spermatozoa untiltheeggs arereadytobefertilized.
Thebasiccomponents ofthe femalesystem arepairedovaries, whichempty theirmature
oocytes (eggs) viathecalyces(Calyx) intothelateraloviduct whichunitetoform thecommon
(median)oviduct.
Thegonopore (opening)ofthe commonoviductisusuallyconcealedinaninflectionof the body
wallthattypicallyformsacavity, thegenitalchamber.
Thischamberserves asacapulatorypouchduringmatingandthus isoften knownas thebursa
copulatrix.Its external opening isthevulva.
Inmanyinsects thevulva isnarrowandthegenitalchamberbecomesanenclosed pouchor
tubereferred to asthe Vagina. 7

8. Two types of ectodermal glandsopen into
the genital chamber
. The first is the spermatheca which stores spermatoza until
they are needed for egg fertilization. The spermatheca is single
and sac-like with a slender duct, and often has a diverticulum
that forms a tubular spermathecal gland. The gland or
glandular cells within the storage part of the spermatheca
provide nourishment to the contained spermatozoa.
The second type of ectodermal gland, known collectively as
accessory glands, opens more posteriorly in the genital
chamber.
8

9. Each ovary is composed of a cluster of egg or ovarian
tubes, the ovarioles, each consisting of a terminal
filament, a germarium (in which mitosis gives rise to
primary oocytes), a vitellarium (in which oocytes grow by
deposition of yolk in a process known as vitellogenesis)
and a pedicel. An ovariole contains a series of
developing oocytes each surrounded by a layer of follicle
cells forming an epithelium (the oocyte with its epithelium
is termed a follicle), the youngest oocytes occur near the
apical germarium and the most mature near the pedicel.

10. Accessory glands of the female reproductive tract are often called as
colleterial or cement glands, because their secretions surround and protect
the eggs or cement them to the substrate. e.g. egg case production in
mantis, ootheca formation in cockroach, Venom production in bees.

11. OOGENESIS
OOGENESIS IS THE PROCESS OF THE PRODUCTION OF
EGG CELLS THAT TAKES PLACE IN THE OVARIES OF
FEMALES .
THE PRODUCTION OR DEVELOPMENT OF AN OVUM .
IT IS DEVELOPED FROM THE PRIMARY OOCYTE BY
MATURATION .
THE PRIMODIAL CELLS IN THE THE OVARIOLE PASS
THROUGH DIFFERENT STAGES OF DEVELOPMENT
BEFORE BECOMING MATURE OVA .

12. TYPES OF OVARIOLES
(I) PANIOSTIC OVARIOLE:LACKSSPECIALIZEDNUTRITIVECELLSSOTHATIT
CONTAINSONLYASTRINGOFFOLLICLES,WITHTHEOOCYTESOBTAINING
NUTRIENTSFROMTHEHAEMOLYMPHVIATHEFOLLICULAREPITHELIUM.E.G.
COCKROACH.OVARIOLESOFTHEOTHERTWOCONTAINSTROPHOCYTES(NURSE
CELLS)THATCONTRIBUTETOTHENUTRITIONOFTHEDEVELOPINGOOCYTES
. (II)TELOTROPHIC OVARIOLE: (ACROTROPHIC)THETROPHOCYTESARE
CONFINEDTOTHEGERMARIUMANDREMAINCONNECTEDTOTHEOOCYTESBY
CYTOPLASMICSTRANDSASTHEOOCYTESMOVEDOWNTHEOVARIOLE,E.G.BUGS.
(III) POLYTROPHIC OVARIOLE:ANUMBEROFTROPHOCYTESARECONNECTED
TOEACHOOCYTEANDMOVEDOWNTHEOVARIOLEWITHIT,PROVIDINGNUTRIENTSUNTIL
DEPLETED,THUSINDIVIDUALOOCYTESALTERNATEWITHGROUPSOFSMALLER
TROPHOCYTES.E.G.MOTHSANDFLIES..

13. Male reproductive system
 THE MAIN FUNCTIONS OF THE MALE REPRODUCTIVE SYSTEM ARE THE PRODUCTION AND STORAGE OF
SPERMATOZOAAND THEIR TRANSPORT IN A VIABLE STATE TO THE REPRODUCTIVE TRACT OF THE
FEMALE.
 MORPHOLOGICALLY, THE MALE TRACT CONSISTS OF PAIRED TESTES, EACH CONTAINING A SERIES OF
TESTICULAR TUBES OR FOLLICLES (IN WHICH SPERMATOZOAARE PRODUCED) WHICH OPEN SEPARATELY
INTO THE MESODERMALLY DERIVED SPERM DUCT OR VAS DEFERENS WHICH EXPANDS POSTERIORLY TO
FORM A SPERM STORAGE ORGAN OR SEMINAL VESICLE.
 TUBULAR PAIRED ACCESSORY GLANDS ARE FORMED AS DIVERTICULA OF THE VASA DEFERENTIA.
SOMETIMES THE VASA DEFERENTIA THEMSELVES ARE GLANDULAR AND FULFIL THE FUNCTIONS OF
ACCESSORY GLANDS.
 THE PAIRED VASA DEFERENTIA UNITE WHERE THEY LEAD INTO THE ECTODERMALLY DERIVED
EJACULATORY DUCT (THE TUBE THAT TRANSPORTS THE SEMEN OR THE SPERM TO THE GONOPORE).
 ACCESSORY GLANDS ARE 1-3 PAIR, EITHER MESODERMAL OF ECTODERMAL IN ORIGIN AND ASSOCIATED
WITH VASA DEFERENTIA OR EJACULATORY DUCT. ITS FUNCTION IS TO PRODUCE SEMINAL FLUID AND

15. 15

16. 1 Testis :
• lie above the gut and connected to the body wall through translucent ducts
• consists of number of oval shaped follicles covered by a peritoneal membrane
• testis is completely enveloped within a scrotum
Structure of follicle divided into a series of zones by the presence of the sperms in different stages of
development
(i) Germarium : contains spermatogonia which undergo multiplication
(ii) Zone of growth: spermatogonia increase in size with mitosis and form spermatocyte
(iii) Zone of division: spermatocytes undergo meiosis and give rise to spermatids
(iv) Zone of transformation : spermatids get transformed in to spermatozoa Spermatozoa enclosed
in testicular cyst cells from which they are released in to vasa efferens
16

17. 2. Vasa deferens :formedbytheunionofvasa
efferens receivesthespermsfromtestisandallow
theirtransporttotheejaculatoryduct
3. Seminal vesicles: vasadeferens enlarge
posteriorly intoasacforstorageofspermatozoa
4. Ejaculatory duct:formedbytheunionof
boththevasadeferens posteriorly terminalsection
ofejaculatoryductisenclosedinamalecopulatory
organoraedeagusorpenis
5. Accessory glands: 1-3pairsofglands
openintotheejaculatoryductTheirsecretion
facilitatesspermtransmission frommaletofemale
Mushroomglandsincockroachesandmantidsas
appearmushrooms
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18. SPERMATOGENESIS
At the distal end of each testis follicle is the germarium,
in which the germ cells divide to produce spermatogonia
(cells which divide mitotically to produce spermatocytes;
spermatocytes divide meiotically to produce spermatids)
(Fig. 12.5). In Orthoptera, Blattodea, Homoptera and
Lepidoptera, the spermatogonia probably obtain
nutriment from a large apical cell with which they have
cytoplasmic connections, while in Diptera and
Heteroptera an apical syncytium performs a similar
function .
18

19. Three zones of development are commonly recognized below the germarium
(1) a zone of growth, in which the primary spermatogonia, enclosed in cysts, divide and
increase in size to form spermatocytes;
(2) a zone of maturation and reduction, in which each spermatocyte undergoes the two
meiotic divisions to produce spermatids;
(3) a zone of transformation, in which the spermatids develop into spermatozoa, a process
known as spermiogenesis
The number of sperm ultimately produced by a cyst depends on the number of
spermatogonial divisions and this is fairly constant for a species. Normally four spermatozoa
are produced from each spermatocyte
19

20. Spermiogenesis
Thespermatidproducedatmeiosis istypicallyaroundedcellcontainingnormalcellorganelles.Itsubsequentlybecomes
modifiedtoformthespermandthisprocessof spermiogenesis .
Acrosome.Theacrosomeisderived,atleastinpart,fromGolgimaterial,whichinspermatocytesisscatteredthroughthe
cytoplasmintheformof dictyosomes.
Nucleus.Intheearlyspermatidof grasshoppersthenucleusappearstohaveatypicalinterphasestructurewiththefibrils,
whichconstitutethebasicmorphologicalunitsofthechromosomes
Mitochondria.Inthespermatid,themitochondriafusetoformasinglelargebody,thenebenkern,consistingofanouter
limitingmembraneandacentralpool ofmitochondrialcomponents.Thenebenkern separatesintotwomitochondrial
derivativesassociatedwiththedevelopingaxialfilamentimmediatelybehindthenucleus.
Centrioleandaxialfilament.Youngspermatidscontaintwocentriolesorientedatrightanglestoeachotherandeach
composed,asinmostcells,ofninetripletsoftubules.Onegivesrisetotheaxialfilament,butultimatelybothcentrioles
disappear.Thetubulesoftheaxialfilamentgrowoutfromthecentrioleandfinallyextendthelengthofthesperm’
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21. thank you