Plant oxidative status under ozone pollution as predictor for aphid population growth: The case of Metopolophium dirhodum (Hemiptera: Aphididae) in Triticum aestivum (Poales: Poaceae)

Ozone is a secondary air pollutant that affects plants and animals through several physiological mechanisms that involve changes in redox status. However, the consequences of ozone pollution on aphids are not well understood. Therefore, we have experimentally tested: if oxidative stress on the host plant affects lipid peroxidation in aphids or aphid population growth. Wheat plants (Triticum aestivum) were exposed to 140 p.p.b. of ozone or filtered air in open top chambers for three consecutive days and Metopolophium dirhodum (Walker, 1849, Hemiptera: Aphididae) aphids were transferred to the plants immediately after ozone exposure or 72 h later. Ozone exposure reduced antioxidant potential within plant tissues and had no effect on plants' lipid peroxidation. Lipid peroxidation in aphids fed upon these plants was similar among treatments. Although aphids successfully colonised the plants in all the treatments, the populations established on plants immediately after ozone exposure grew at higher rates than those established 72 h after ozone exposure had ended, independently of ozone level. In conclusion, aphids were tolerant to plant mediated effects of ozone. Therefore, a greater attention should be put in the direct effects of ozone on M. dirhodum - T. aestivum interaction.