Effects of repeated and delayed exposure to codling moth eggs on reproduction of Trichogramma cacoeciae and T. principium (Hymenoptera: Trichogrammatidae) females

Abstract

Laboratory experiments were conducted to evaluate the influence of repeated and delayed exposure to fresh codling moth eggs on the parasitism of Trichogramma cacoeciae Marchal and T. principium Sug. et Sor. The percentage survival of T. cacoeciae and T. principium females significantly declined as the number of exposure times increased (or as the females became older). The highest mean number of parasitized eggs and F 1 progeny were recorded during the first day of exposure, after which they declined. However, the percentage mortality of parasitized eggs of T. cacoeciae and T. principium was negatively correlated with repeated exposure. When the exposure of T. cacoeciae and T. principium females to host eggs was delayed for 3 days after emergence, the percentage of oviposited females was not affected; however, the mean number of parasitized eggs, F 1 individuals and the percentage mortality declined significantly. The current study provided essential information necessary to determine the optimal timing of parasitoid releases to increase the efficiency of T. cacoeciae and T. principium against codling moth.

Impact of Trichogramma parasitoid age on the outcome of multiparasitism in the factitious host eggs of Chinese oak silkworm, Antheraea pernyi

“…We assumed that TO females deprived from A. pernyi host for such a long period of time (i.e., more than 4 days) resulted in intensive oosorption and consequently the parasitization ability of TO females decreased. The variation in multiparasitism rates in our results did confirm that parasitism ability of TO on A. pernyi host was largely age dependent (Fleury and Bouletreau 1993;Godfray 1994;Garcia et al 2001;Makee 2005;Huang et al 2017).…”

“…Therefore, in the context of possible development of mass production of T. ostriniae using a multiparasitism-based method, further experiments are needed to evaluate how factors such as parasitoid age could modulate emergence rate from A. pernyi host (during multiparasitism). Several studies demonstrated that Trichogramma parasitoid age could impact parasitism and progeny emergence from different host eggs in monoparasitism (Garcia et al 2001, Hegazi andKhafagi 2001;Hohmann and Luck 2004;Makee 2005;Ayvaz et al 2008;Pizzol et al 2012). However, parasitoid developmental rates and agerelated oviposition patterns (syn-ovigenic or pro-ovigenic) could also have influence on the outcomes of multiparasitism between parasitoids (Cusumano et al 2012;Harvey et al 2013).…”