Intraguild Predation on the Parasitoid Wasp Aphidius colemani by the Predator Aphidoletes aphidimyza: Effect of Host Plant Cultivars

In a tri-trophic system, guild members may engage in IntraGuild Predation (IGP) and their interactions may be affected by the host plants. We used a system composed of the predatory gall midge, Aphidoletes aphidimyza Rondani, the parasitoid wasp, Aphidius colemani Viereck, and the melon aphid, Aphis gossypii Glover, to test how the outputs of IGP were affected by two cultivars of cucumber (Khasib and Karim). IGP between natural enemies were examined on a single cucumber plant of each cultivar infested with mummified, parasitized or healthy individuals of melon aphid in a controlled environment room at ۲۵±۲°C, ۶۵±۵% RH, and a photoperiod of ۱۶L: ۸D hours. According to the results, A. aphidimyza was the effective predator of parasitized aphids, but not on mummified ones. In treatments with either healthy or parasitized aphids alone, A. aphidimyza consumed significantly less numbers of healthy aphids or parasitized ones on Karim cultivar. When predators were provided with healthy aphids and parasitized aphids together on plants, the risk for parasitized aphids of being predated upon by A. aphidimyza larvae was significantly reduced on Karim cultivar. Manly’s Preference Index for healthy aphids on Karim cultivar was significantly the highest. The results revealed that the strength of IGP on IG-prey on Karim cultivar was less than Khasib cultivar. Therefore, better control of melon aphid population can be expected on this cultivar.

Keywords:

Aphis gossypii , Cucumber cultivars , Interspecific interactions , Predatory gall midge. , خیار , کنترل بیولوژیک , شته جالیز , زنبور پارازیتوئید , پشه شکارگر