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Intl. J. of Molecular Zoology, 2012, Vol.2, No.2, 13
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22
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Thus, life depends on a continuous in put of energy.
This energy flows in one way direction through every
cell and organism, and through the ecosphere.
Accordingly, an organism is considered as open
system with respect to energy. While, the insects are a
major component of almost terrestrial or fresh water
communities; very little appreciation has been paid for
studying their energetic (Shaurub et al., 2001).
Finally, it could be concluded that the SIT depending
on inherited sterility is usually not a “stand alone”
technology, but also, a complementary component of
an area wide and sustainable long-term strategy in
Integrated Pest Management (IPM) (El-shall and
Mohamed, 2005). Compatible control methods, such
as plant extracts, that possess a source for naturally
occurring substances acting, as feeding and insect
growth deterrents may be synergistic when integrated
with the SIT. Since, the present data indicated that the
combination treatment of irradiation and Barnoof
extracts resulted in less consumed food and more food
utilization efficiency compare to the use of irradiation
alone. In addition the reduction of growth index due to
combined treatments would lead to the emerging of
undersized female moths. These females may lay
fewer eggs than female resulting from irradiation
treatments only (Mohamed, 2004). Furthermore, the
fertility is a fundamental parameter in the assessment
of any control measure. The combination treatments
of Barnoof extracts and gamma irradiation on
A.
ipsilon
decreased the fertility of moths less than that
resulted from the irradiation treatments alone. Further
critical evaluations need to be conduct; both in the
laboratory and in the field, on the effect of gamma
irradiation and/or plant extract for assessment the use
of plant extracts in suppress the pest population before
introducing the SIT.
2 Materials and Methods
The laboratory strain of
A. ipsilon
reared on castor
leaves,
Ricinus communis
at 26
℃-
28
℃
and 60±5%
R.H. The source of gamma radiation used during the
present study was from a Cobalt 60(
60
Co) irradiator;
the dose rate of irradiation source was 145 rad/min.
The full-grown male pupae of
A. ipsilon
were
irradiated 24-48 hours before adult emergence (male
line) with low doses of gamma radiation (100 Gy; 150
Gy) in a 100cc carton cups. After adult emergence,
fifteen groups of each dose (1 treated male
×
1 normal
female) were made in each treatment. A group of
fifteen untreated pupae were also kept as a control
(N♂
×
N♀). Each pair (male and female) was kept in
750cc cylindrical glass cage supplied with 10% sugar
solution. The daily-deposited eggs of non-irradiated
females were collected, counted, recorded and kept for
calculating the % of egg hatch. The sterility from
control and control of reproduction were computed (as
follow) in response to the reproductive performance of
the treated parental insects and also in their F
1
progeny involved in different treatments. Control of
reproduction given by (V
c
-V
t
) / V
c
*100 where:
V
c
=viable number of eggs in the control
V
t
=the viable number of eggs in the treated insects
(Seth and Shegal, 1992).
To continue the F
1
generation for male line, newly
hatched larvae resulting from irradiated P
1
males were
kept in groups in glass jars provided with castor bean
leaves. Each four hundred larvae of the second instar
of each treatment were transferred to a glass jar
(500cc), furnished with a thin layer of saw dust to
absorb excess humidity and covered with muslin fixed
with a rubber band. Rearing was continued in the
same way until the larvae reached the last larval instar,
then were transferred individually to small plastic
vials (each, 10cc) containing moistened saw dust for
pupation. Newly formed pupae were collected, sexed
and each sex was kept separately in a plastic container
with moistened sawdust and covered as usual with
muslin cloth. At each treatment, the newly emerged
males of the first generation (F
1
) descendant of
irradiated parental males were paired with newly
emerged untreated females using all possible crosses
between them in order to obtain F
1
generation. The
crossing scheme for this study is illustrated as follows:
P
1
Crosses: (Normal male
×
Normal female) serve as a
control [Treated male
×
Normal female (male line)]
F
1
Crosses: (Normal male
×
Normal female) serve as a
control
F
1
Male (male line)
×
Normal female
[Normal male
×
F
1
Female (male line)]