Learning in foraging female can change the parameters in the functional response
of aphid parasitoids (Byeon et al. 2011). Within a series of experimental assays,
Rasekh et al. (2010a, b, c, d) surveyed the effects of various parameters on the
foraging behavior of Lysiphlebus fabarum (Marshall), as parasitoid of black bean
aphid, Aphis fabae Scopoli. They found no significant differences between young
and old females, suggesting that age had also no effect on proportional time
allocation to various activities during patch exploitation (Rasekh et al. 2010b). On
the same way, encounters with con-specific females had no effect on foraging
behavior of this species, which was interpreted as a consequence of cuticular
camouflage interferes with conspecific recognition (Rasekh et al. 2010d).
Several different factors, e.g. interactions with other natural enemies, soil media
composition, etc. have also been used to study the functional response of aphid
parasitoids (Rashki et al. 2013; Mottaghinia et al. 2017). Considering the complication and considerable number of the factors affecting the functional responses, there
are yet some ambiguities in the relevance of the experiments dealing in this respect
(Hassell et al. 1977). It should be point out that these kinds of experiments are
conducting under laboratory condition, where parasitoids are forced to remain in the
patch (van Steenis and El-Khawass 1995), that is not consistent with the real
conditions. Therefore, the functional response may simply have altered in natural
condition, but the basic consequences can be predicted, at least (Houck and Strauss
1985). Recently, the effect of interspecific interactions on parasitism rate and
efficiency of different species have been investigated. Accordingly, it has been
revealed that interspecific interaction negatively affecting the parasitism rate of
A. matricariae and P. volucre against second and third instars of green peach
aphid (Tazerouni et al. 2016).
9.3.4 Host Stage Preference
An important aspect of behavioral and physiological ecology of the aphid parasitoids
is the host preference which guarantees the survival of the next generation. In a broad
sense, it includes various definitions ranging from habitat preference to host instar
selection. The host range pattern of the aphid parasiotids discussed in a separate
section, is a matter of their evolutionary history connected with their host aphid’s
evolution and host plant distribution (Žikić et al. 2017). Ignoring the expanded
definition, the behavioral host preference including the host nymphal instar selection, has been considered as important criteria in selecting the efficient aphid
parasitoids, both at the time of mass rearing and in their practical application for
achieving a successful biological control. In general, the larvae of aphid parasitoids
can successfully develop in all nymphal instars, while their size is highly variable,
which means different value of the food resources. The early nymphal instars may
even be smaller than the ovipositing female parasitoid (Mackauer 1986; Mackauer
and Kambhampati 1988b). However, the female parasitoid mainly foraging within
9 Aphid Parasitoids: Aphidiinae (Hym., Braconidae)
349
of aphid parasitoids (Byeon et al. 2011). Within a series of experimental assays,
Rasekh et al. (2010a, b, c, d) surveyed the effects of various parameters on the
foraging behavior of Lysiphlebus fabarum (Marshall), as parasitoid of black bean
aphid, Aphis fabae Scopoli. They found no significant differences between young
and old females, suggesting that age had also no effect on proportional time
allocation to various activities during patch exploitation (Rasekh et al. 2010b). On
the same way, encounters with con-specific females had no effect on foraging
behavior of this species, which was interpreted as a consequence of cuticular
camouflage interferes with conspecific recognition (Rasekh et al. 2010d).
Several different factors, e.g. interactions with other natural enemies, soil media
composition, etc. have also been used to study the functional response of aphid
parasitoids (Rashki et al. 2013; Mottaghinia et al. 2017). Considering the complication and considerable number of the factors affecting the functional responses, there
are yet some ambiguities in the relevance of the experiments dealing in this respect
(Hassell et al. 1977). It should be point out that these kinds of experiments are
conducting under laboratory condition, where parasitoids are forced to remain in the
patch (van Steenis and El-Khawass 1995), that is not consistent with the real
conditions. Therefore, the functional response may simply have altered in natural
condition, but the basic consequences can be predicted, at least (Houck and Strauss
1985). Recently, the effect of interspecific interactions on parasitism rate and
efficiency of different species have been investigated. Accordingly, it has been
revealed that interspecific interaction negatively affecting the parasitism rate of
A. matricariae and P. volucre against second and third instars of green peach
aphid (Tazerouni et al. 2016).
9.3.4 Host Stage Preference
An important aspect of behavioral and physiological ecology of the aphid parasitoids
is the host preference which guarantees the survival of the next generation. In a broad
sense, it includes various definitions ranging from habitat preference to host instar
selection. The host range pattern of the aphid parasiotids discussed in a separate
section, is a matter of their evolutionary history connected with their host aphid’s
evolution and host plant distribution (Žikić et al. 2017). Ignoring the expanded
definition, the behavioral host preference including the host nymphal instar selection, has been considered as important criteria in selecting the efficient aphid
parasitoids, both at the time of mass rearing and in their practical application for
achieving a successful biological control. In general, the larvae of aphid parasitoids
can successfully develop in all nymphal instars, while their size is highly variable,
which means different value of the food resources. The early nymphal instars may
even be smaller than the ovipositing female parasitoid (Mackauer 1986; Mackauer
and Kambhampati 1988b). However, the female parasitoid mainly foraging within
9 Aphid Parasitoids: Aphidiinae (Hym., Braconidae)
349