Abstract:
Worldwide distribution of the Date Palm Hopper (DPH)
,
Ommatissus lybicus
de
Bergevin along with intensive regional chemical and
cultural practices to control this pest
provide a basis for development of high genetic div
ergence. This genetic divergence can
result in demographically distinct populations. In
this study, the demographic parameters
of three genetically diverged Iranian populations o
f DPH (Bam, Jiroft, and Tezerj) were
determined on two date palm cultivars (Berhi and Kh
unizi). The age-stage, two-sex life
table theory was used to unveil biological differen
ces among these populations. All
experiments were carried out in a laboratory at 27±
2 ̊C, 65±5% RH, and a photoperiod of
14:10 (L: D) hour. The results revealed significant
differences in life history traits and
growth parameters of different populations. The sho
rtest development time was observed
in the Bam population (75.86 and 85.03 days on Berh
i and Khunizi, respectively). The
highest values of the intrinsic rate of increase (
r
) and finite rate of increase (
λ
) were
detected in Bam population (0.0377 and 1.0433 per d
ay on Berhi as well as 0.0284 and
1.0288 per day on Khunizi, respectively). Based on
these results, we can consider Bam as
an aggressive population with higher infestation ra
te compared with the other
populations due to its higher
r
and
λ
values as well as shorter mean generation time on
both host cultivars. The significant differences in
life history traits and variation in
population growth parameters may suggest the presen
ce of cryptic species among these
populations. It can stem from the high genetic dive
rgence among DPH populations which
may be orchestrated by mismanagement of the pest.
Keywords
: Berhi date, Demographic parameters, Dubas bug, Kh
unizi date, Insect population
growth.
