OBSEHVATlONS
1
Aul acophora fovei colis
SP ERMA1'0 GEN ESI S :
REPRJDJCTIVE ORGANS:
t
The insect Aulacophora foveicolis
possesses a single testis. It is dorselly placed
at the right side of the fifth abdominal segment.
The testis is round and orange coloured surrounded
by a thick fibrous tissue (F.I.g. 1) 'ld th a few
nuclei in i t (F.I.g. 2).
J!:ERMATOGONlAL C.FLLS :
The spermatogonial cells lie packed
together near the testt cular wall forming a
group or such cells. These cells are formed by
the ur;kno'Wtl repeated divisions of the primordial
germ cells. As they are packed together their
original shape can not be recognised. Ee.ch cell
measures about 15'
7
~
to 17 ..u, its nucleus
..u to 10.-U and a well stained nucleolus about
1.)1 in diameter (F.I.g. 1). '1hese cells multiply
by mitotic division. lhe chromosomal threads
appear 'tlithin the nucleus in prophase stage
(Fig. 1). The nuclear membrane disappears and
the chromosomes are seen at the equator
connected with spindle fibres in metaphase
stage. ln few cells
the centriole is also
visible at tw poles connected with the spindle
fibres ( Fi8. 3). J..t the onset of the anaphase
stage the chromosomes can be seen separating to
move towards their respective poles ( f1~. 3}.
At this stage the nuclear membrane is lost. ln
the following telophase stage the chromo somes
become clumped together and appear as deeply
stained bodies at tW'O poles (F.lg. 4). After the
nuclear division, the cytoplasmic division
follows with the result two cells are formed.
PRIMARY SP'ElMATOCYTE CJiLLS
~
'lhe primary spermatocyte cells are
formed by the repeated divisions of the
spermatogonial cells. These cells are larger
than the secondary spermatocyte cells present
in the testicular lumen, Primary spennatocyte cells
show a remarkable growth phase during which they
enlarge in size. Each cell measures about 11 -4 to
13 ..u, its nucleus about 8 .u to 9 .u and its
nucleolus 1 .u in diameter.
1he primary spermatocyte cell undergoes
meiotic division. 1he chromosomes are first
organised to form the leptotene stage in which
the chromosomal threads appear scattered in the
nucleoplasm. A deeply stained nucleolus can be
well recognised very close to the nuclear
membrane. A very small unstained vacuole is seen
w1 thin the nucleoJ.us in some of the cells (Fig. 5}.
In the following zygotene stage the -pairing of
homologous chromo somal threads takes place but 1 t
is difficult to follow the course of pairing. At
this stage the chromoscmal threads become thicker
and stain deeply. 'lhe nucleolus is still visible
in some of the ceJ.ls (Fig.6). After this in
pachytene the open ends of the threads get oriented
towards the nucleolus and the loOped condi t1on now
becomes visible. It is difficult to count the
number of loops due to their overlapping but they
are certainly not more then the haploid number
of chromosomes (lt'ig.7). Further in di,~).Q_~ne
the loops contract~ and became much shorter in
length. At this stage the loops loose their
orientation and are seen scattered in the
nucleus, the ring bivalants are absent, 1hc
homologous pair do not separate completely but
are attached together at certain points (fig.8).
'l'he paired chromosomes contract more and more and
stain deeply in diakinesis stage, At the end of
di!"kinesis the nuclear membrane disappears and
the dot like chromosomes are seen scattered in the
cytoplasm Ol.g.9). Later, these chromosomes get
arranged at the equator in metaphase (Fig. 10). At
anaphase stage the chromosomes move towards their
respective poles (F:lg.11). It is now followed by
the Telophase stage where the chromosomes
aggresate after they have reached to their
respective t>Oles ( Fig.12}, This nuclear divisi-on is
now followed by the cytoplaS!Ilic 'division and tw
secondary spermatocyte cells are formed (Fig, 13).
--
SECONDARY SP hBHATO CYTE Cl!LLS :
The secondary spermatocyte cells are
smaller in size than the primary spermatocyte cells.
They measure approximately 8 .A1 to 10 ..u, their
nucleus 6...1.1 to ?.At and nucleolus 1Al in diameter.
Airing the second meiotic division, in prophase
11
stage, the chromo somal threads appear v.1. thin
the nucleus 0'1g.14). ln metaphase stage the
chromosomes become short,condensed and clumped
together at the equatorial plate (li'1.g.15'). lhe
two sets of chromosomes separate to reach their
respective poles in anaphase (Fig.16}. At
telophase stage the chromosomes aggregate at the
poles for nuclear reorganisation (li'1.g.17). 'Ibis
is followed by cytokinesis With the result of
which two spennat1ds are fonned.
Sl:' mllOGENESLS :
The spermatid nuCleus is quickly
refonned and the chromatin material becomes
scattered in the form of delicate netwrk. During
early spermiogenesis gradual concentration of the
chromatin material takes place at the inner
surface of the nuclear membrane. 'lhis encloses
a central cavity. l'be nuclear vesicle remains
unstained, where as the con centra ted chromat1.n
material stains deeply (Fig.18). The chromatin
material appears as a horse shoe shaped structure.
1.
distinct, well stained granule, the acrosome
appears 1d thj_n the acroblast. 'Ihe acroblast has
12
been found in close contact 14th the nuclear
membrane of the spermatid (F!g,19). lhe centriole
could not be recognised until the axial filament
\/as formed, In some of the spei'I!latids the
centriole appears as a darll: granule at one end of
the fHament (Fig,2Q), Certain mDrphological
changes have been noticed in the spermatids
before changing in to mature spei'I!ls. In this con
the absence of vacuoles in the spermatid nuclei
is remarkable, .F'irst of all the spermatid becomes
fusiform, 'lhe nucleus changes into a pear shaped
structure 'vlith its anterior pointed acrosomal
end and a broad posterior end to which the sperm
tail is found attached. 'l'b.e middle portion of the
IS
nucleusAbroad so the whole structure looks like
a leaf (.Flg,21}, On further elongation of the nuclear
part of the spermatid the lateral margins of the
nat nucleus appear to roll up and fuse, (F1g.22 and
23). Thus the sperm nucleus assumes a new shape
and looks like a tube i, e, enclosing a space YJi thin
1 t (Fig, 23 and 2Y.). ln advanced stages the nucleus
becomes more condensed and stains deeply. lbe
elongated hollow space gradually disappears due to
the condensation of the chromatin material of the
nucleus {Fig,25). In
mature sperm the nucleus
stains deeply 14th a long faint tail attached to its
posterior broad end (F:I.g,26).
13
Aspidomorpha san t1 cru~
Rli' Will CTl V.l!;
ORGMS
In an adult specimen of Aspidomorpha
s!mticruca.e both the testes are situated side by
side at the posterior end of the abdominal
segments. 'lbese are orange coloured small baJ.llike
structures. Each testis is surrounded by a thin
fiprous sheath containing a few nuclei in it,
(Pig. 27). 'lbe fibrous sheath of the testis
bounds numerous groups of cells ( F.ig. 28). lbese
groups of cells are seen packed together VIi thin the
testicular lumen. All the c'ells contained in such a
group, are found at one stage of cell division.
SP EJ.i.{Al'OGONl AL
CliLLS
~
Arter repeated divisions, the primordial
germ cells develop into the spermatogonial cells.
These cells are spherical measuring apo roxima tely
13 ..u to 15' ..u, their nucleus 7 .AJ. to 9 ..u and. the
nucleolus is 1 ..u in diameter. These cells are
generally seen in resting stage. The cytoplasm of
these cells U agranular \,bile the nucleoplasm
appears to be granular (F.I.g. 29). lhe mitotic
stages of spennatogonial cells are not abundant.
In a cell, at the beginning of the nuclear
activity the chromosomal threa.ds become visible
in prophase stage (F.!.g. 30}. In metaphase, deeply
stained condensed chromosomes get arranged on the
equatorial plate (Fig. 30). In the anaphase stage
the chromosomes are dra'tJM towards their respective
-poles (Fig. 31} and. at telophase the chromosomes
become clumped together and appear as deeply stained
masses at each pole (Fig. 32}. lt is followed by
cytokinesis and t'IIO cells are foxmed (Ii~g. 33).
'l'he primary spexmatocyte cells are formed
due to the repeated divisions of the spermatogonial
cells. 1hese cells are abundant in the testes. At their
intellJhase such cells measure approximately 10 .JU to
11JJ 1 their nucleus 6 .u to 7 .ll and nucleolus 1.u in
diameter. 'lhese primary spexmatocyte cells are found
15
closely packed v.1. th each other therefore their cells
boundaries are not regular. 1 t has been found that
the cytoplasm of these cells is clear \Pile thP
nucleoplasm is granular in appearance, lt is due to
the chromatin material present in it,
1he nuclear contents are activated for
meiotic behaviour and in the subsequent leptotene
stage the nuclear threads become prominant and
fcund scattered in the nucleus. At this stage it is
di ffi cult to determine the number of loops and
the ends of threads. Ihe nucleolus remuns attached
to the nuclear membrane as a deeply stained body,
A small nuclear vacuole has been found within the
nucleo""lus (Fig, 34A), In the folloWing zygotene stage
~
the pairing of the homologous chromosomal threads
sets in but i t is difficult to trace the paired
threads. The nucleolus is still visible quite close
to the inner border of the
nuclear membrane (.fig, 35}.
Soon after the pairing of the homologous chromosomes,
the nucleolus shifts towards one side at the base
of the loops in pachytene)>tage. lt is difficult to
count the number of the loops as they overlap each
other (Fig, 36}, The diplotene stage could not be
traced, The chromosomes show further condensation and
16
stain deeply. 'I'his leads to diakinesis stage
where the nuclear membrane breaks down and deeply
stained rod like haploid number of chromosomes are
seen scattered in the cytoplasm (Fig. 37}.
:::I.Jbsequ ently in metaphase deeply stained
and highly condensed chromo somes arrange themselves
at the equator (Fig. 38}. Later in anaphase the
the chromosomes move towards their respective poles
( l'ig. 39}. In tbe following telophase the cell
becomes elongated and the chromosomes aggregate at
each pillle later the cytoplasmic division follows,
w1 th the result tw secondary spematocyte cells
are fonned (Fig. 34-B).
SECONDAI!Y
SPER-iATQQKTE
C1JLLS :
The secondary spennatocyte cells are much
smaller as compared to the primary spennatocyte cells.
These cells measure approximately 7 ...u to 8 ..u, their
nucleus 4..u to 6 ...u and nucleolus approximately 1..u in
diameter. As soon as the secondary spermatocyte cells
')'!.
So on
are .formed their nuclei undergo reoAganisation.
after the resting period a faint network of chromosomal
threads appear in the nucleus, ln prophase stage a well
stained nucleolus is also seen close to the nuclear
17
membrane (1'1(;. 4o). Lnter the chromosomes become
very much condensed, stain deeply and arrange
themselves on the equator in metaphase. 'lhe nuclear
membrane and the nucleolus disappear at this sLage
(Fig. 41). 'lhis stage is followed by anaphase "Where
the tw sets of the chromo somes separate from each
other (F'I.g. 41). Later on these sets of Chromosomes
are dravm towards their respective poles in
telophase. At this stage the cell becomes elongated
ahd the chromosomes fuse together to form a thick
mass of chromatin material at each pole Olg. 42-A}.
After the nuclear division of the secondazy
spermatocyte cells the cytoplasmic division occurs
with the result tw:> spermatids are formed (Fig.42-.ci}.
SP EFMlOGENESI S :
LUring the process of the spermiogenesis
of the spermatid, the chromatin material Shows
reorganise. tion. Soon the chromatin aggregates at the
inner surface of the nuclear membrane and a large
unstained nuclear vesicle appears within the nucleus
Olg. 42-B} • .A deeply stained acrosomal granula
becomes visible @i te close to the nuclear membrane
( 1-:t.g. 43). LUe to further condensation of the
18
spem11t1d nucleus a c1e"r unl!tained v"cuole ie seen
w1 thin it ( 1<'1~. 44). 'l'he condensation of the nucleus
containues. A deeply stained granule, the centriole
has been observed connected w1 th the projected
cytoplasmic tail (Fig. 45).
1~ow
the spermatid nucleus
becomes more elongated And nattened and contains one
or two vacuoles within it (F1g. 46). ln more elongated
--
nuclei 3 to 4 vacuoles appear w1 th in it. At this
I;
stage the anterior poined acrosomaJ. end and the
•
posterior broad nagellar end of the nucleus become
differentiated (l'lg. 47). In the successive stages of
elongation of the spennatids
en
the nuCleus becomes
more flatted
at 1 ts middle region and appears like a
A
trypanosome. The vacuoles are completely lost. ln more
advanced stages, the lateral margins o:f
nucleus roll u-p
~
e
the nattend
A
unite so that the nucleus encloses
a tubular space -within it {Fig. 48,49 & 5o). It ma7
be mentioned here that the posterior broad nagellar
end of the nucleus also rolls up, therefore the
nagellum becomes tubular. further elongation and
condensation of the nuclear portion results in the
foimation of a mature sperm which has darkly stained
nucleus and faintly stained tubular tail(.F'l..g. 51). 1'he
mature sperms remain in the form of a bundle in the
testicular lumen (Fig. 52).
19
Monolrota
SPEll-lATOGEl-IESIS ;
REP BOW CTl VE
ORGMS.. :
In the adult specimens of Monolyp ta there
is a single testis which is small and round in shape
and lie in the fifth abdominal segment. 'lhe testis
is si 'b..lated on the dorsal side and appears as a
bright reddish orange sac. lt is found surrounded
by a fibrous sheath -with a few nuclei in 1 t (Fig. 5'3}.
From the peripheral fibrous sheath a few incomplete
partitions extend w.1. thin the testicular cavity. lhe
testis contains many groups in which identical cells
are found packed together (F.!..g. 53) • .After a series of
divisions the primordial germ cells produce
Spermatogonial cells. 1hese cells are almost
identical to the primordial germ cells therefore it
is quite difficult to differentiate them.
20
.W E.RMTOGCitU.AL
C:CLLS •
'lhe spermatogonial cells are few in number
as compared to all other cells .Jlich are found. in
the testis. A
~~permatogonial
measuring approximately 18
.ll
cell
to 20
is oval in shape
.ll
and its nucleus
nearly 7 .,u in diameter, Jlt its interphase stage a
stained. nucleolus is present in the nucleus. 'I'he
spermatogonial cells mul t1ply mitotically and increase
in number, At the beginning of the nuclear activity
faintly stained. chromosomal threads become visible
at prophase stage (Fig, 54). IUring meatphase the
nuclear membrane disappears and deeply stained
condensed chromosomes aet aligned on the equator.
(F.!.g. 55), In the following anaphase stage the
chromosomes move towards their respective pole!! from
the equatorial
region (F.I..g,
55).
At
telophase deeply stained compact masses of chromatin
material are visible at two poles (F.!.g. 56).
Later on these masses form the
resting nuclei of the primary spermatocyte cells.
PRIMABY
&>EEMATOCYTE
C.bLLS '
Variations in the size of the primary
spermatocyte cells have been obsel"V'ed, 'lbe smallest
21
size of the primazy spennatocyte is neal'l.Y 12 ..u
'flhile fully develo-ped one measures 18 .,u in diameter.
lheir nuclei are 6.-u to 9.-u in diameter containing
a nucleolus in each of them at the resting stage,
The nuclear contents are activated for the meiotic
division. At first the chromosomal. threads are seen
scattered in whole of the nucleus during leptotene
stage, It is difficult to mark out the ends of the
threads at this stage (F.ig, 57). In the subsequent
zygotene stage the pairing of the homologous
chromosomal thread takes place but it is difficult to
follow the course of pairing, At this stage the
chromosomal threads are thicker and stain deeply
{Fig. 58). In the follolJing pachytene stage the
chromosomal. threads fo:rm loops. It is diffirul.t to
count the number of l.oOps as they overlap each other
( F'ig. 59). FUrther in diplotene stage the loOps
contract and become shorter in length, At this stage
the loOps loose their orientation and scatter
in
the nucleus. 'lhe homologous pairs do not separate
completelY but remain attached w1 th each other at
certain points therefore a few stages of chiasma and ring
bivalents have also been observed in the squash
preparations O'ig, 6o). 'lhe paired chromosomes
22
contract more and more and stain deeply 1n the
d1ak1nes1s stage. At the end of diakinesis the
nuclear membrane disappear and rod and dot shaped
chromosomes are seen scattered 1n the cytoplasm
(Fig. 61}. This is followed by metaphase where
deeply stained and condensed chromosomes are seen
at the equator. The spindle is also clearly
visible (Fig. 62). In anaphase stage the chromosomes
are drawn to,..ards their respective poles (Fig. 63).
In its telophase stage the chromosomes become
clumped at each pole (Fig. 63} which later
on form the nuclei of the seconde.zy spermatocyte
cells.
SE<XI.NDABY
&-' ERMATOCYTE
CELLS :
Arter the first meiotic division of the
primary spennatocytes, the resultants are called
secondary spermatocyte cells. lbese cells form groups
where they are found packed together. These cells
measure approximately 7 .u to 8 ...u the nucleus about
4.5 Jl to 5 ...u
w1 th the nucleolus about 1...u in diameter.
In prophase stage faint- chromosomal threads appear
in the nucleoplasm (Fig. 64). In the following
metaphase stage the chromosomes become condensed,
stain deeply and lie at the equator (.[!lg. 65}.
23
In anaphase the tw sets of chromosomes move apart
so as to reach their respective poles (big. 64},
.Finally, in telophase the chromo somes become
condensed at each pole. It is follo....ed by the
cytoplasmic division as a result of ..tllch t1o0
spermatids are fonned,
SPERMIOGENESIS :
'Ihe spennatids
~ich
are fonned undergo
the process of spermiohi stogene sis. ln ne'olil.y formed
spermatid the chromatin material gets aggregated on
the inner surface of the nuclear membrane and stains
deeply, 'Ihis encloses the nuclear vesicle 1Jllch
remain conspicuous for some period, A darkly stained
aero somal granule also appears quite close to the
nuclear membrane (F.i.g, 66}, 'Ihe elongating spennatid
has been marked t:Lth certain characteristic t'eatures.
The chromatin material of the
spe:rn~atid
becomes
more condensed and the nuclear vesicle reduces in
its aize at the early stages of morphogenesis. A
very small granule, the centriole, appears near the
nuclear membral'le (Fig. 67). Now the nucleus becomes
elongated and contains t...o to three very small
unstained vacuoles, At this stage the chromatin
material stains deeply. 'lhe sperm nucleus becomes
...
pointed at the anterior and broad at the posterior
ends (Fig, 68), lhe acrosome takes its position at
the anterior pointed end 1 while the tail of the
spenn remains connected 'Ill. th the posterior broad
end of the nucleus. D..! ring further elonga t1.on the
vacuoles become smaller in size but increase in
number, The chromatin material become more condensed
so that it appears granular and stains deeply(P.I.g.69).
lt is remarkable to note here that the posterior
~
portion of the nucleus stains deeply in comp ari s on to
~
its middle and the anterior regions. 'lhis indicates that
the condensation of the nuclear material star.ts from
posteri<rr to middle end then to anterior regions
successively (Fig. 70). On further condensation of
the nucleus the vacuoles are lost completely and at
last the sperm nucleus becowes f'ilementous wL th the
pointed acrosome at the apex and tail attached to the
posterior broad end. l'he sperm nucleus stains
deeply but the tail stains faintly (Fig, 71 and 72},
.
25
Laccop tera _quadr1maculc.ta
SP ~ATOG J!1J ESI s
lill' OOIJJ CTI VE
:
ORG.Il1~ S
ln an adult beetle or this species a pair
of testes are found at the posterior end or the
abdominal segment. 'lhese are round or oval in shape
and orange in colour. The testicular sheath is thin
and is formed of fibrous connective tiswe with a
few nuclei in it. The spermatogonial cells, the
primary and secondary spe:nna to oy te cells, the
spe:nnatids and the sperms are found in groups within
the testicular lumen. These groups are found separated
from each other by fibrous septas therefore various
groups of similar cells are seen clearly in the
section of the testes (Fig. 73 and 74).
S1? ERMATOGONI.Ak_ CFLLS :
lhe spennatogonial cells are fo.rmed by
the repeated division of primordial ge:nn cells and
lie near the testicular sheath. 'lhese are $herical
26
in shape. Each of these measure 12..u to 16.u, their
nuclei 8..u to 10..u and nucleolus 1.u in diameter.
Their cytoplasm is clear and agranular but the
nucleoplasm is granular and contains a well stained
nucleolus in it. 'l'hese cells ,undergo mitosis. In
prophase stage the fine chromosomal threads become
visible ld.thin the boundary of the nuclear membrane
(Fig. 75'). However nuclear membrane disappears and
deeply stained condensed chromosomes lie on the
equatorial plate in the cytoplaSIII in metaphase stage
<Fig. 76), ln the follold.ng anaphase the chromosomes
move apart to reach their respective poles (F.I.g.77).
ln telophase the chromosomes become clumped together
at both the. poles OJ!J} 78). lhe nuclear division
is now followed by the cytoplasmic division with the
result tlriO primary spennatocyte cells are fo:nned.
PBIMABY
Si?EHUTOCYTE
C:EL1S ;
lhe primary spermatocyte cells are abundant
as compared to the other cells found in the testicular
lumen, This indicates that the nuclear divisi.on of
these cells is in quick succession and later on
followed by a growth phase. The primary spermatocyte
cells measure about 10 .u, their nuclei about 6 .u to 8 ..u
27
end nucleolus 1.-U in diameter. l t has been found
that the position of the nucleous is very close to
the nuclear membrane. It is remarkable to note
here that a very small nuclear vacuole appears
within the nucleolus (Fig, 79). At the start of
the meiotic division the chromosomal threads appears
as a deeply stained body attached to the nuclear
memb:rane w1 th an unstained vacuole tJi thin it ( F'1?• 8o}.
In the subsquent zygotene stage the pairing of the
homologous chromosomal threads takes place. ln some
of the C6lls the existence of the nucleolus has
been noticed even at this stage \Fig, 81}. After the
pairing of the homologous chromosomes the loOps are
formed in pachytene stage \ltlere the nucleolus becomes
excentric and lies at the base of the 1oops. ln this
case also it is difficult to count the number of loOps
(Fi~. 82), FUrther, in diplotene stage the loops
contract more and become shorter in length (Fig. 8)},
During diakinesis the chromosomes become very thick
and short and stained deeply w1 th haema toxyline
( li'1g. 84), At the end of the diakinesis the nuclear
membrane disap-pears and the chromosomes become
scattered in the form of dots, rods
and ring bivalents
in the cytoplasm (Fig. 84), lhis is followed by
metaphase in which deeply stained and very much
28
condensed chromosomes arrange themselves at the
equatorial plate (Fig. 85'}. In the following
anaphase stage the chromosomes are drawn towards
their respective poles (Fig. 85). Later, in
telophase the chromosomal sets appear as deeply
stained clumped masses at two poles.O'ig. 86),
This is now followed by cytokinesis w1 th the
result tw secondary spennatocyte cells are
formed.
S.ECOliiD.Am
SPEEMATOCYTE
CErlLS :
lhe resultant secondary spennatocyte cells
are comparatively smaller in size than the primary
spermatocytes. ll6ch cell measures 7.». to 8..u, its
nucleus 4.5.». to 5.». and the nucleolus 1JU in
diameter. lhese cells are round in groups in the
testicular lumen. After a very short resting period
the chromosomal contents become activated for the
division and at prophase stage thread like chromosomes
appear and the nucleolus starts loosing its identity
(F.!.g. 87). At metaphase the nuclear membrane is lost
and vel1foruch condensed chromosomes lie on the equator
(Fig. 88). In the following anaphase stage the
chromosomes separate and are drawn towards their
respective poles (Fig.88), F.inaJ..lT at telaphase deeply
29
stained compact chromatin mass aggregates at two
poles (F1.g, 89), .Arter a short period these form
the resting nucl.ei of the spennatids,
In an early spermatid, during the
period of nuclear reorganisation the scattered
netwrk of chromatin material becomes condensed on
the inner surface of the nuclear membrane. As a
resu1 t of this condensation a clear nuclear vesicle
appears in the nucleoplasm (F.I..g, 90}, A deeply
stained body, the aero somal granule appears quite
close to the nucl.ear membrane <:Fig. 91}, <l:>ndensation
of the sperm nucleus starts w1 th the gradual elongation
of the nucleus. The acrosome shifts towards the
anterior end and remain attached to the nucl.ear
membrane. Initially the spermatid nucleus contains a
large unstained vacuole w.1. thin it (Fig, 92). On
further elognation and condensation of the chromatin
materiel one or tw vacuoles appear in the nucleus
(Fig, 93). ln the subsquen t stages of elongation of
the spermatid nucleus the acrosomal end becomes
pointed end indicates it santerior end while broad
flagellar end indicates posterior region (F.l..g, 94),
:w
At this stage the nucleus stains deeply but the
nagellum stains lightly (I1.g. 95). 'lhe condensation
of the chromosomal material continues. lt has been
noticed that as the number of vacuoles increases in
the nucleus, their si7e becomes smaller ( F'i.g. 96}.
'lhese vacuoles later on fuse together forming a
hollow space within the nucleus O!l.g. 97). l<'lnally
due to condensation of the nucleus the hollow
s~ace
disappears and a well stained nucleus of a
mature sperm is formed (Fig. 98). The sperm bundles
have been found in bundles ( 1'1 g. 99).
31
Oocassida
R.l!I'HOWCTIVE
bundicata
ORGANS
A pair of testes are situated on the
dorsolateral side of the 'Posterior abdominal segments
in male adult beetles. lhe 'WSll of the testis is
formed of a fibrous tissue (Fig. 100}. lhe prdimordial
germ cells are very few in number and due to overlapping could not be photographed. 'Ihe spermatogonial
cells, the primary and secondary spennatocyte cells,
the spennatid
and the sperms fDrm groups \11 thin the
testicular lumen.
~1ATOGONIAL
CELLS
'lhe spennatogonial cells are formed due to
repeated mitotic divisions of the primordial germ
cells. These cells are spherical in shape measuring
about 13 ..11 to 15' ..u, their nucleus 6 ..u and nucleolus
1 ..u in diameter. In few cases tWJ or fou>'< nucl.ei
have been found forming rosette pattern i.e. the
inner end of cells taper to meet at a -central. point.
v ..
In th6re cells the cytonlasm :1.6 clear and agranular
whereas the nucleoplasre is granu1ar0'1g. 101). lhe
spennatcgonial cells undergo mitosis after a short
resting -period, In prophase stage the chromo somal
threads become visible (Fig, 102). Later on the
nuclear membrane disapnears and chromosomes come to
lie in the cytoplasm at the equatortal region in
metaphase stage (Fig. 103), At anaphase the
chromosomes move apart from the equatorial plate to
reach their respective poles. And finally at
teloephase stage the chromosomes form compact masses
at both the poles {F'ig, 104), lhis is followed by
the cytoplasmic division with the result t...o
primary spermatocyte cells are formed,
'Xhe primary spermatocyte cells are abundant
as observed in squash and smear preparations. l'hese
cells undergo a growth phase. lhe size of the cell is
nearly 10 .-U to 11 ...u, their nucleus
5' .-U
to 6 ...u and
nucleolus 1.-U in diameter. As soon as the growth phase
is over the primary spennatccyte cell enter into the
first meiotic division. 'lbe chromatin material. of the
nucleus is activated for division, The nucleolus
shtftJ 2.nd cnmes closP to the rrucle<>r membrane, l•'ine,
fRintly stained chromosomal threads appeflr in
leptotene stage (Fiz. 105). lhis is followed by the
zygotene stage where homologous chromosomes pair and st<>in
deeply, At this sta.ge the chromosomal threads lie at
different directions showing no definite orientation
Uig, 106), 'lhe nueleolus :1.4 still visible in the
nucleus as a deeply stained granule, In pachytene
stage the loops of the chromosomal threads become
distinct and get oriented at the opposite end of the
nucleolus. It is difficult to count the number of
lOOJ;l s as they overlap each other Ol.g, 107}. In the
forthcoming diplotene stage the loOps contract and
bedome shorter • 'I'he bivalants form chiasma but the
rings are absent 01g. 108). ln diakinesis the
chromosomes become condensed and appear as dumbels
and stain deeply w.1. th haematoxyline Olg. 109). A.t
the end of the diaJcinosis the nuclear membrane
disanpears and subsequently in metapha.se stage the
chromosomes lie at the equatorial plate in the
cytoplasm (Fig, 106), At anaphase the chromosomal
halves separate and move towards their respective
poles this stage could not be photographed. The
chromosomes after reaching their respective poles
appear as deeply condensed masses at telophase stage
stat;e \l<lc. 110), lt b
now followed !Jy the
cytoplasmic division of the cell.
SJ:i..CONDJUlY
SP Jill<l.A'.lCJ CY Th CtLL S :
Un completion of first meiotic division the
primary spermatocyte cells, t'WO secondary spenEatocyte
cells are formed,
lhese measure approvirnateJy 7 ...u to 8...u
their nucleus 4_.u to
5 .ll
aJJd the nucleolus 1 _,u in
diameter. The chromosomal material of these newly
formed cells soon reorganises to undergo second meiotic
division. Well s taln ed chromo somal threads appear at
prophase stage Ulg, 111}. Later, in the metaphase
stage the nuclear membrane disappears and the
chromosomes come to lie in the cytoplasm at the equatorial
plate O'ig. 112}. In anaphase the chromosomes are
dra'tlrl towards their respective poles (Fig. 113}. In the
subsequent telephase stage compact chromatin masses
are seen at both the poles (l'lg. 112), This is followed
by the cytoplasmic division.
As a result of the second meiotic division of
the secondary speiTila tocy te cells two spermatids are fo:nrnecL
Iiefore forming a mature sperm the spermatid undergoes
through the process of spermiohi stogene sis. iol.rst of
3~
all the chroma tin mnteri a1 get dispersed in the
nucleus and later becomes condensed all around at
the inner margin of the nuclear membrane and an
unstained nuclear vesicle appears w1 thin the nucleus
( .F'i~l· 114), A deeply stained acrosoma1 gmule now
appears within the acroblast situated close to the
nuclear membrane. A small deeply stainee. granule,
the centriole also become visible on the nuclear
membrane (Fig. 114). 'lhe sperm nucleus now starts
elongating and the acrosome occupies its anterior
apical position. On further elongation of the
nucleus the chromatin material condenses more and
more, The centriole appears as a fine granule
connected w.l. th the projected cytoplasmic tail. On
further elongation of the spermatid, it is
remarkable to note that the midcUe pcrrtion of the
nucleus become broader. 1he vacuoles in the
nucleus do not appear at all. 1he chromatin granules
do not appear in the nucleus therefore 1 t stains
uniformly. However, in few cases one or tw small
vacuoles have been seen in 1 t (F.!. g. 115). In more
advanced stages of elongating nucleus the condensation
of the chromatin material continues (F.!.g. 116 and 117) •
.R.
and/finaly forms the nuclear part of the mature sperm
I
/\
which stains deeply 'o/1 th haematoxyline Olg. 118},
'l'he tail remains attached to the posterior part of
the nucleus and stains lightly,