Bactrocera Zonata Male Reproductive System

Journal of Applied Sciences Research, 6(9): 1346-1351, 2010
© 2010, INSInet Publication
Anatomical and Histological Studies on the Peach Fruit Fly, Bactrocera Zonata (Saund.)
Male Reproductive System
1
1
N.F. Shehata, 2M.W.F. Younes and 1Y.A. Mahmoud
Department of plant protection, National Research Centre, Dokki, Cairo, Egypt.
2
Department of Zoology, Faculty of Science, Menoufia University.
Abstract: The present study included studies on the external morphology of male Bactrocera zonata
(Saund.) abdomen. Also, this study involved detailed description of the internal anatomy of male
reproductive system and the histology of its gonads. This study indicated that the male B. zonata
reproductive organs reached its maturity at the end of the first week (6th or 7th day) of male life. Also,
histological studies showed that spermatogenesis process extended to the 12th week (about 84 days) of
male life.
Key words: Bactrocera zonata, Reproductive system, Anatomy, Histology, Gonads.
INTRODUCTION
The peach fruit fly, Bactrocera zonata (Saund.)
considered one of the most destructive fruit pests in
several parts of the world. It is of fundamental
importance to understand the external and internal
structures of the reproductive system in the target
insect for solving any scientific problem related to this
system. Studies on the external morphology of the male
B.zonata (Saund.) abdomen was previously recorded.[3]
The present study involved more informations about the
external morphology of the male B.zonata abdomen in
addition to the detailed description of the internal
anatomy of the reproductive system besides the
histology of its gonads during the twelve weeks of
male life.
MATERIALS AND METHODS
The tested flies of B.Zonata were obtained from a
permanent colony reared at the NRC laboratory under
controlled temperature of about 25± 2 c and relative
humidity of 60-65%. Larvae were reared on wheat-bran
meduim and adult food was consisted of sugar and
protein hydrolyzate enzymatic at a ratio of 3:1,
respectively[8]. Rearing technique was performed in
cages (30× 15 × 15cm) covered with muslin, offered
with adult food and water[5].
Anatomical preparations of the male reproductive
system, were conducted microscopically in Ringer’s
invertebrate solution [8].
Histological preparations were performed by
cutting of the male abdomens, dissected in Ringer’s
Invertabrate solution, fixed in alcoholic Bouin’s
solution, washed and dehydrated through graded series
of isopropyl alcohol and filtered with and embeded in
paraffin wax.
Results:
A- External Anatomy of B. zonata Male Abdomen:
The abdomen of male B.zonata (Figs.1,2) consists of
nine segments, its view from side indicates the
overlapping sclerites. On each side of tergite three, a
raw of setae (the pecten) was observed and the 5th
tergite with a pair of lightly depressed areas
(ceromata). [from data sheet on quarantine pest (Dacus
zonatus) prepared by CABI and EPPO for the EU
under contact 90/399003]. Each pecten consists of
about twenty black setae (not appear in the figure).
Segments from 6 to 9 are modified to produce the
copulatory apparatus (ca.). The unfunctional apparatus
showed externally coiled on itself and covered the
lower portion of the 7th segment besides segments 8
and 9 (ventral view). Detailed morphological studies on
the peach fruit fly developmental stages were
previously recorded.[3]
B- Internal Anatomy of B.zonata Male Reproductive
System: The male reproductive organs (Fig.3) consists
of pear-shaped (undivided sacs) yellow testes (TES.).
Their long axis placed longitudinally in the body
cavity.The apical distal portion (ADP) of each testis
curved outwards. From each testis, a fine vas deferens
(VSD) running backwards and connects with a common
median seminal vesicle (VSS). The vas efferens (VSE)
is a long and narrow tube leading out from the
posterior end of the vesicula seminalis (VSS) and
running into the reservoir. The ductus ejaculatorious
Corresponding Author: N.F. Shehata, Department of plant protection, National Research Centre, Dokki, Cairo, Egypt.
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Fig. 3: The reproductive system of male B.zonata
adult.
glands (ACG) are four pairs of tubular structure; differ
in their length; open in the vesicula seminalis. Three
pairs are short and the fourth pair are very long and
convoluted on themselves. Each accessory gland of the
fourth long pair branched to two branches from about
the half distal end.
Fig. 1: Dorsal view of male B.zonata adult.
Fig. 2: Ventral view of male B.zonata adult. (st.)
sternite, (c.a) copulatory apparatus.
(DEJ) is a comparatively short tube which comes out
from the top of the reservoir, and runs backwards to
led into and run through the aedeagus (AED) which
ended with four claspers (CL). The male accessory
C- Histology of B.zonata Male Testes: The testis of
mature B.zonata is about 0.9 mm long excluded the
apical distal portion (ADP). The longitudinal section
(Fig.5) indicated that the spermatogonial (s.g.) and
spermatocyte (s.c.) cells at different stages of the
development occupy the whole (ADP). At the base of
ADP and the apical portion of the testis body, each
spermatocyte undergoes the meiotic division to produce
spermatids (st.).Thus the ADP and the apical portion of
the testis' body represent the growth and maturation
zone. Extending down, spermatogenesis process was
perfomed where spermatid cells in cysts (in each cyst,
cells are in a stage of the process of synchronous
transformation) developed into spermatozoa, the zone
of transformation which occupy about the 2/3 length of
the testis’ body. The rest terminal portion occupied by
the seminal vesicle (s.v.) (vesicula seminalis). The wall
of the testis consists of an apical layer [follicular
epithelium (f.e.)] standing on a basement membrane.
Generally, spormatogenesis in the peach fruit fly,
B.zonata follows the general pattern for other Diptera[1]
In the three days old male testis (Fig. 4), the
spermatogonial cells occupied the (ADP) while the
basal portion of the (ADP) and about the ¼ apical part
of the testis body were full of sprematocyte cells in
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Fig. 4: L.S. in testis from a 3- day - old male
B.zonata adult. X 1000
Fig. 5: L.S. in testis from a 1- week - old male
B.zonata adult. X 1000
different stages of division. At about the terminal ¼
length of the testis the seminal vesicle was clearly
detected. The rest middle portion of the testis body
occupied by sperm bundles (s.b).
The testis of one week old male (fig.5 ) indicated
that about ¾ length of the (ADP) occupied by
spermatogonial cells while its basal portion and the
apical part of the testis' body full of spermatocyte
cysts. About the 1/3 terminal part of the tesits’ body
occupied by the seminal vesicle. The rest middle part
of the testis body full of sperm bundles, spermatids
still attached with sperm bundles and some free sperms
(f.s.).
Progression of spermatogenesis process clearly
observed in two weeks old male testis. The whole
testis’ body (involved the seminal vesicle) was crowded
with sperm bundles, spermatids attached with sperm
bundles and free sperm. The sprmatids appeared large
and posses nuclei nearly in the size of that of
spermatocytes. Spermatocyte cells in cysts clearly
observed in the apical portion of the testis’ body.
Testes of three and four weeks old males are
largely similar, (Figs.7, 8 ) showed that the lower ¾
length of the testis’ body involved seminal vesicle
(s.v.)occupied by sperm bundles (s.b.), spermatids
(st.)attached with sperm bundles and free sperms(f.s.).
The (ADP) was disappeared in these figures (during
histological preparations) and the apical portion of the
testis were occupied by spermatogonia (s.g.) and
spermatocyte (s.c.) cells in various stages of
development.
It is worthy to mention that more sperm bundles
clearly appeared in the four weeks (Fig. 8) than in the
three weeks (Fig.7) old male testis.
In the testis of five weeks old male (Fig. 9), the apical
¼ part of the testis’ body was occupied by
spermatogonia and spermatocyte cells. Approximately,
the rest part of the testis’ size was full of sperm
bundles, spermatids attached with sperm bundles and
released sperms.
At seven weeks old males, about half the size of
the testis’ body (apical portion) occupied by
spermatocyte cells in different stages of division. The
seminal vesicle appeared in the terminal portion of the
testis. In the rest size of the testis more free sperms
(f.s) than spermatids (st.) attached with sperm bundles
(s.b.) besides the sperm bundles, could be observed
(Fig.10).
In ten weeks old testis (Fig.11), more sperm
bundles, spermatids attached with sperm bundles and
free sperms at the half upper portion of the tesis were
clearly detected while the rest half occupied by the
seminal vesicle. The (ADP) and apical portion of the
testis’ body were full of spermatogonia and
spermatocyte cells at various stages of development.
Figure (12) clearly indicated the continuation of
spermatogenesis process till the twelfth week of male
life. This figure showed an increase in the
spermatogonial and spermatocyte cells till occupied the
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Fig. 6: L.S. in testis from a 2- week - old male
B.zonata adult. X 1000
Fig. 7: L.S. in testis from a 3- week - old male
B.zonata adult. X 1000
Fig. 8: L.S. in testis from a 4- week - old male
B.zonata adult. X 1000
Fig. 9: L.S. in testis from a 5- week - old male
B.zonata adult. X 1000
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Fig. 10: L.S. in testis from a 7- week - old male
B.zonata adult. X 1000
Fig. 12: L.S. in testis from a 12- week - old male
B.zonata adult. X 500
of free sperms (f.s.), spermatids (st.) attached with
sperm bundles and few sperm bundles (sb.) were also
observed.
Fig. 11: L.S. in testis from a 10- week - old male
B.zonata adult. X 500
long ADP and about the half apical size of the testis’
body. The seminal vesicle appeared at the terminal
portion of the testis’ body while the rest area was full
Discussion and Conclusion: Histological studies
indicated that the male Bactrocera zonata (Saund.) is
immature reproductively. Its reproductive organs
reached maturity at the end of the first week (6th or 7th
day) of male life where all spermatogenesis stages
clearly observed till the appearance of some free sperm
in the testis’ body (Fig.4).
Several researches assured the previous information
in some tephrited flies, they found that attraction of;
Dacus (Bactrocera) dorsalis (Hendel) male to methyl
eugenol and Dacus (Bactrocera) tryoni to cue-lure
commenced some days after emergence[4,6,10]. Another
researcher recorded that responding of Dacus
(Bactorcera) cucurbitae (Coq.) male to cue-lure
increased with age and corresponded with sexual
maturity[2].
At the end of the 20th century, some authors
reported that B.zonata (Saund.) males of 1-5 days old
did not respond to methyl-eugenol lures; only about
20% responded at 6 days old and about 98% responded
at 13-days old. They also stated that this level of
response to the lure did not alter significantly after 13
days old males but remained at about 90%. They again
recorded that once males had achieved reproductive
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maturity ageing factor did not influence the behavioural
capacity to respond to methyl eugenol at least up to
the age of 80 days.[7]
Present histological studies indicated that the
effeciency of B.zonata testes extended to twelve weeks
(about 84 days) of male life.
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