A. kuehniella, S. cerealella and H. armigera were 79.17, 92.90 and 57.72 respectively (Farazmand et al. 2007; Vaez et al. 2009). Some external factors affect
fecundity of these wasps. The size of host egg determines the available resources
and ultimately the size, fecundity and fitness of the emerging parasitoid. On the other
hand, fecundity of Trichogramma spp. depends on size and quality of host egg
(Bulut 1990). Larger T. brassicae females with higher fecundity were obtained when
reared on the angoumois grain moth compared to the Indian meal moth (Hosseini
Bai et al. 2006). Temperature and photoperiod are the other factors that affect
fecundity. Shirazi (2006) reported daily fecundity of T. chilonis on C. cephalonica
at 25 and 30
C to be 6.69 and 12.73 respectively. He also mentioned that more eggs
were laid at a photoperiod of 14: 10 h (L: D). Fecundity of T. embryophagum was
16.61, 26.33 and 26.46 and that of the T. pinoti was 12.33, 30.93 and 28.50 eggs at
22, 24 and 26
C respectively (Ranjbar-Aghdam and Attaran 2014).
Feeding prior to release, markedly increased fecundity and longevity of
Trichogramma (Southard and Houseweart 1982; Bigler 1994; Reznik et al. 1997;
Soares et al. 2012). Attaran et al. (2004) reported that fecundity of starved
T. brassicae were 20.57 and 19.60 on A. kuehniella and S. cerealella, while that
of the fed wasps by honey reached to 71.35 and 56.7 respectively. Karimi-Malati and
Hatami (2005, 2010) also showed that nutrition plays an important role in increasing
of longevity of T. brassicae, as honey supplement led to 8d-increased longevity.
Yeast had no effect on longevity.
6.6.3 Life Table Parameters
According to Andrewartha and Birch (1954) demographic parameters are the best
indicators of fitness of a population and are suitable criteria for comparing physiological states of different species, populations, etc. The most common demographic
parameters are intrinsic rate of increase (r m ), finite rate of increase (λ), gross
reproductive rate (GRR), net reproductive rate (R 0 ), mean generation time (T) and
doubling time (DT) (Carey 1993; Ebert 1999). Local populations of
trichogrammatids were compared in regards of life table parameters in a few studies.
However, in many studies estimation of parameters such as intrinsic rate of increase
or net reproductive rate was neglected due to difficulty of calculations. These
parameters are used for monitoring fitness of the parasitoid at successive generations
(Table 6.2).
Direct comparison among different works may be misleading because the parasitoids are very sensitive to physical conditions. On the other hand, punctuality
among different researchers in treating the wasps is not similar. Data analysis
methods also can cause some deviations. Disregarding such sources of variation,
T. brassicae seems to be partially superior to the T. pintoi and T. embryophagum.
This is deducible from higher intrinsic rate of increase and reproductive rates and
shorter generation time. However, role of host seems to be crucial. For example,
P. interpunctella is a poor host while S. cereallella is a suitable one for T. brassicae.
6 Egg Parasitoids: Chalcidoidea with Particular Emphasis on Trichogrammatidae
209
fecundity of these wasps. The size of host egg determines the available resources
and ultimately the size, fecundity and fitness of the emerging parasitoid. On the other
hand, fecundity of Trichogramma spp. depends on size and quality of host egg
(Bulut 1990). Larger T. brassicae females with higher fecundity were obtained when
reared on the angoumois grain moth compared to the Indian meal moth (Hosseini
Bai et al. 2006). Temperature and photoperiod are the other factors that affect
fecundity. Shirazi (2006) reported daily fecundity of T. chilonis on C. cephalonica
at 25 and 30
C to be 6.69 and 12.73 respectively. He also mentioned that more eggs
were laid at a photoperiod of 14: 10 h (L: D). Fecundity of T. embryophagum was
16.61, 26.33 and 26.46 and that of the T. pinoti was 12.33, 30.93 and 28.50 eggs at
22, 24 and 26
C respectively (Ranjbar-Aghdam and Attaran 2014).
Feeding prior to release, markedly increased fecundity and longevity of
Trichogramma (Southard and Houseweart 1982; Bigler 1994; Reznik et al. 1997;
Soares et al. 2012). Attaran et al. (2004) reported that fecundity of starved
T. brassicae were 20.57 and 19.60 on A. kuehniella and S. cerealella, while that
of the fed wasps by honey reached to 71.35 and 56.7 respectively. Karimi-Malati and
Hatami (2005, 2010) also showed that nutrition plays an important role in increasing
of longevity of T. brassicae, as honey supplement led to 8d-increased longevity.
Yeast had no effect on longevity.
6.6.3 Life Table Parameters
According to Andrewartha and Birch (1954) demographic parameters are the best
indicators of fitness of a population and are suitable criteria for comparing physiological states of different species, populations, etc. The most common demographic
parameters are intrinsic rate of increase (r m ), finite rate of increase (λ), gross
reproductive rate (GRR), net reproductive rate (R 0 ), mean generation time (T) and
doubling time (DT) (Carey 1993; Ebert 1999). Local populations of
trichogrammatids were compared in regards of life table parameters in a few studies.
However, in many studies estimation of parameters such as intrinsic rate of increase
or net reproductive rate was neglected due to difficulty of calculations. These
parameters are used for monitoring fitness of the parasitoid at successive generations
(Table 6.2).
Direct comparison among different works may be misleading because the parasitoids are very sensitive to physical conditions. On the other hand, punctuality
among different researchers in treating the wasps is not similar. Data analysis
methods also can cause some deviations. Disregarding such sources of variation,
T. brassicae seems to be partially superior to the T. pintoi and T. embryophagum.
This is deducible from higher intrinsic rate of increase and reproductive rates and
shorter generation time. However, role of host seems to be crucial. For example,
P. interpunctella is a poor host while S. cereallella is a suitable one for T. brassicae.
6 Egg Parasitoids: Chalcidoidea with Particular Emphasis on Trichogrammatidae
209