considered as an optimal temperature in which development time is independent of
host quality. Total protein content could properly explain variations (Nozad-Bonab
and Iranipour 2013).
Host Size It is considered as an effective factor in host quality. Often larger hosts
are preferable although this statement is not always true. In gregarious parasitoids
such as Ooencyrtus spp. the size of the wasp depends on number of broods within a
single host egg (Iranipour et al. 2013b; Ahmadpour et al. 2013). In Solitary parasitoids, however, it depends on other factors. BenaMolaei et al. (2018a) showed that
between two populations of E. integriceps, Varamin population has slightly heavier
eggs than Tabriz population (0.81 vs. 0.75 μg), although the diameter of eggs was
very close (1.07 vs. 1.06 mm). Such a small difference led to slightly larger
parasitoids with corresponding detectable although often insignificant advantages.
Females affected slightly more than males but the size difference was significant in
both. Allahyari et al. (2002) obtained 7 and 11% smaller T. vassilievi and T. grandis
respectively on Podissus maculiventris compared to E. integriceps eggs. In contrast,
Asgari et al. (2001) observed no significant difference in T. semistriatus obtained
from either E. integriceps or G. lineatum eggs.
Host Age In some cases, parasitoid size is a function of other factors like host age.
Host age determines embryogenesis level and it determines in turn host quality. In an
experiment, 0–5 day old eggs of E. integriceps were offered to two populations of
T. vassilievi (BenaMolaei et al. 2015a). No parasitoid, but six males developed
within 5-day old eggs. Number of the parasitized eggs, emergence rate, sex ratio,
total fecundity and wasp size was similar in 0–2 day old eggs but declined in older
eggs. This allows harvesting done every third day that may decrease costs in mass
cultures. Tabriz population was smaller and therefore suffered more seriously from
host age than Varamin population. For example, the sex ratio was 44–47% in
3–4 day old eggs in the former population vs. 61–68% in the latter one. However,
the difference was only in females and males were of the same size. This suggests
that more vigor parasitoids should be selected for mass culture initiation. Development time differed as small as 0.6 days or less, although such minor differences were
significant. Fecundity also was affected by host age. Fecundity was 40–60% higher
at commence in control compared to wasps emerged from 2–4 d old eggs. However,
a partial compensation in subsequent days occurred. Nasiri et al. (2020) studied
functional response and host preference of O. fecundus among three kinds of hosts.
Fresh host eggs, 6 d old developed host eggs and 8 d old paerasitized eggs by
T. grandis. Effect of development of host embryo was very worse than previous
parasitism. Females of O. fecundus preferred parasitized eggs to developed ones and
fresh eggs to both. No swithing was observed in lower rates of preferred hosts. It was
concluded that O. fecundus can play a minor negative role on host/parasitoid ratio,
because it often parasitizes late season eggs that often are parasitized or developed
and therefore kill more Trissolcus than E. integriceps offspring. Similar results by
different Platygastroid egg parasitoids and different host species was obtained. For
example T.semistriatus on E. integriceps, G. lineatum, Dolycoris baccarum,
Eurydema ornata (L.), and Holcostethus vernalis (Wolff) (Kivan and Kiliç 2004),
8 Superfamily Platygastroidea: Natural Enemies of True Bugs, Moths, Other. . .
319
host quality. Total protein content could properly explain variations (Nozad-Bonab
and Iranipour 2013).
Host Size It is considered as an effective factor in host quality. Often larger hosts
are preferable although this statement is not always true. In gregarious parasitoids
such as Ooencyrtus spp. the size of the wasp depends on number of broods within a
single host egg (Iranipour et al. 2013b; Ahmadpour et al. 2013). In Solitary parasitoids, however, it depends on other factors. BenaMolaei et al. (2018a) showed that
between two populations of E. integriceps, Varamin population has slightly heavier
eggs than Tabriz population (0.81 vs. 0.75 μg), although the diameter of eggs was
very close (1.07 vs. 1.06 mm). Such a small difference led to slightly larger
parasitoids with corresponding detectable although often insignificant advantages.
Females affected slightly more than males but the size difference was significant in
both. Allahyari et al. (2002) obtained 7 and 11% smaller T. vassilievi and T. grandis
respectively on Podissus maculiventris compared to E. integriceps eggs. In contrast,
Asgari et al. (2001) observed no significant difference in T. semistriatus obtained
from either E. integriceps or G. lineatum eggs.
Host Age In some cases, parasitoid size is a function of other factors like host age.
Host age determines embryogenesis level and it determines in turn host quality. In an
experiment, 0–5 day old eggs of E. integriceps were offered to two populations of
T. vassilievi (BenaMolaei et al. 2015a). No parasitoid, but six males developed
within 5-day old eggs. Number of the parasitized eggs, emergence rate, sex ratio,
total fecundity and wasp size was similar in 0–2 day old eggs but declined in older
eggs. This allows harvesting done every third day that may decrease costs in mass
cultures. Tabriz population was smaller and therefore suffered more seriously from
host age than Varamin population. For example, the sex ratio was 44–47% in
3–4 day old eggs in the former population vs. 61–68% in the latter one. However,
the difference was only in females and males were of the same size. This suggests
that more vigor parasitoids should be selected for mass culture initiation. Development time differed as small as 0.6 days or less, although such minor differences were
significant. Fecundity also was affected by host age. Fecundity was 40–60% higher
at commence in control compared to wasps emerged from 2–4 d old eggs. However,
a partial compensation in subsequent days occurred. Nasiri et al. (2020) studied
functional response and host preference of O. fecundus among three kinds of hosts.
Fresh host eggs, 6 d old developed host eggs and 8 d old paerasitized eggs by
T. grandis. Effect of development of host embryo was very worse than previous
parasitism. Females of O. fecundus preferred parasitized eggs to developed ones and
fresh eggs to both. No swithing was observed in lower rates of preferred hosts. It was
concluded that O. fecundus can play a minor negative role on host/parasitoid ratio,
because it often parasitizes late season eggs that often are parasitized or developed
and therefore kill more Trissolcus than E. integriceps offspring. Similar results by
different Platygastroid egg parasitoids and different host species was obtained. For
example T.semistriatus on E. integriceps, G. lineatum, Dolycoris baccarum,
Eurydema ornata (L.), and Holcostethus vernalis (Wolff) (Kivan and Kiliç 2004),
8 Superfamily Platygastroidea: Natural Enemies of True Bugs, Moths, Other. . .
319