IRRADIATION OF EGGS AND LARVAE OF Ceratitis capitata (DIPTERA: TEPHRITIDAE) WITH X-RAY TO IMPROVE THE MASS REARING OF THE FRUIT FLY PARASITOID,
Diachasmimorpha longicaudata (HYMENOPTERA: BRACONIDAE)
Aline T. Macedo1, Maylen Gómez1, Gessyca A.G. Araujo1, Beatriz J. Paranhos2, Jair F. Virginio1
1Biofábrica Moscamed Brasil (BMB), Distrito Industrial São Francisco 992, 48.908-000, Juazeiro-BA, Brasil, e-mail: [email protected]. 2Embrapa Semiárido, BR 428, km 152, CP 23, 56.302-970, Petrolina-PE
Introduction
Biological Control using the exotic parasitoid Diachasmimorpha
longicaudata (Ashmead) is an efficient tool for population control of the
Ceratitis capitata (Wiedemann). The success of this control tool depends on
the technologies used in mass rearing process, which ensure proper insect
quality, efficiency, and low costs. The host irradiation application before the
exposure to the parasitism, allows a “clean rearing”, without the emergence
of the pest.
Materials and Methods
The studies were conducted at the Laboratory of Entomology of the
Biofábrica Moscamed Brasil (BMB), Juazeiro, Bahia, Brazil.
The experiment was carried out in three steps:
• First step: was evaluated the effect of X-rays on the viability of C. capitata
eggs of different ages: 12, 24 and 36h-old. Eggs were exposed to the
doses: 0 (control); 2.5; 5; 7.5; 10; 12.5; 15; 17.5; 20, 22.5 and 25 Gy.
• Second step: was evaluated the irradiation effect on egg-pupal yield,
pupal weight, and the emergence of flies using 36h-old eggs and 3rd-
instar larvae with different doses. Doses applied for eggs were the same
as previous, and for larvae were: 0, 5,10, 15, 20, 25, 30, 35, 40, 45, 50, 55
and 60 Gy.
• Third step: larvae that hatched from irradiated eggs with 36h-old and
larvae irradiated at the end of the 3rd-instar were exposure to the
parasitoid.
Results and Discussion
A B
C
Figure 1. Irradiation of eggs and larvae of C.capitata (A, B). Parasitism of
D.longicaudata on irradiated host.
ab
c
d d d d d d d d
a a
b
c
de
e e e e e
a a a a a a a a a a a
0
10
20
30
40
50
60
70
80
90
100
0 2,5 5 7,5 10 12,5 15 17,5 20 22,5 25
Egg
hat
chin
g ra
te
Doses (Gy)12h 24h 36h
Figure 2. Hatching rate in 12, 24 and 36h-old C. capitata eggs exposed to different doses of
X rays. The columns represent the means ± SE. Columns of the same color followed by different letters are
statistically different (Tukey test, p <0.0001).
Figure 3. Emergence of C. capitata adults exposed to X-rays at different stages of
development. Embryonic phase (A) and larval phase (B). The columns represent the means ± SE.
Columns with different letters are statistically different (Tukey test, p <0.0001).
Table 1. Quality parameters of D. longicaudata adults reared on C. capitata larvae, non-
irradiated and irradiated.
Conclusions
The columns represent the means of each parameter evaluated ± standard error
The results show that either 36h-old eggs and 3rd-instar larvae at doses of
10 and 50Gy using X-rays, respectively, constitute a suitable substrate for
the parasitoid development. Further studies should be carried out to evaluate
the fecundity and fertility of D. longicaudata reared on irradiated hosts.
Acknowledgments: We wold like to thank to CNPq for
fellowships
0,0
10,0
20,0
30,0
40,0
50,0
60,0
70,0
80,0
90,0
100,0
0 2,5 5 7,5 10 12,5 15 17,5 20 22,5 25
Fly
Emer
gen
ce (
%)
Dose (GY)
a a
b
c
d d d d d d d 0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60
Fly
em
erg
en
ce
Dose GY
a a
b
c d d d
AB
Non-irradiated
larvae10 Gy 12,5 Gy 15 Gy
Non-irradiated
larvae 40 Gy 50 Gy
Formation of puparia
after 24h (%)99,6 ± 0,40 88,4 ± 5,65 83,0 ± 3,42 79,6 ± 7,12 96,9 ± 1,27 99,8 ± 0,00 99,2 ± 0,00
Pupa weight 8,3 ± 0,08 5,8 ± 0,16 4,6 ± 0,06 3,8 ± 0,15 7,8 ± 0,50 6,6 ± 0,40 6,3 ± 0,29
Emergence of the
parasitoid (%)30,7 ± 3,70 35,4 ± 2,70 47,1 ± 6,70 42,1 ± 7,70 54,6 ± 3,98 56,1 ± 3,96 56,7 ± 3,94
sex ratio 0,32 ± 0,05 0,34 ± 0,04 0,33 ± 0,03 0,33 ± 0,06 0,75 ± 0,02 0,76 ± 0,02 0,77 ± 0,01
Irradiation in the larval stage
Quality Parameters
Irradiation at the embryonic stage