Abstract:
Life history of insect herbivores is unclear after
feeding on mutant lines of many crops.
To shed light, demographic parameters of
Plutella xylostella
on three canola cultivars
(“Zar”, “RGS”, “Talaye”) and their physical mutatio
n-derived lines (“Zar 9-9”, “RGS 8-
1”, “RGS 10-2”, “RGS 8-13” and “Talaye 8-3”) were d
etermined under greenhouse
condition. Methods of life table including the fema
le age specific life table and the age-
stage, two-sex life table were applied. According t
o two-sex life table, there was no
significant difference between demographic paramete
rs of
P. xylostella
on “Talaye” and
“Zar” in comparison with their mutant lines, but si
gnificant differences were observed
between these parameters on mutant lines of “RGS”.
Having suitable cultural traits,
“RGS 8-1” was more susceptible than the other two m
utant lines and its control cultivar
“RGS” in terms of population growth of the pest. Ac
cording to the two-sex life table, the
net reproductive rate (
R
0
), intrinsic rate of increase (
r
), and finite rate of increase (
λ
) were
the highest on RGS 8-1 (98.63 offspring per individ
ual, 0.208 and 1.231 day
-1
,
respectively). Also, population projection showed t
he rapid growth of the pest on the
latter line. There was a little difference between
the same population parameters
estimated by two methods of life table. Investigati
ng some consequences of plant breeding
using radiation techniques on insect fitness not on
ly leads plant breeders to do more
unfailing selections but also provides some enlight
enment in pest management programs
effectively when plantation of such crops is priori
tized.
Keywords
: Age-stage two-sex life table, Diamondback moth, F
emale age-specific life table,
Gamma ray, Insect fitness.
