Effects of Plant Stress on Aphid–Parasitoid Interactions: Drought Improves Aphid Suppression

Abstract Drought events have the potential to mediate tri-trophic interactions. Changes in plant quality influence herbivore performance, which affects prey availability and for natural enemies. Parasitoid wasps are particularly vulnerable these changes since their development is inextricably linked that of prey. However, we know little about indirect effects water limitation on parasitoid especially consequences mild limitation. This study investigated ability a wasp (Aphidius colemani Viereck (Hymenoptera: Braconidae)) suppress aphid (Rhopalosiphum padi L. (Hemiptera: Aphididae)) populations well-watered, mildly stressed, or highly stressed wheat (Triticum aestivum (Poales: Poaceae)). We then role body size behavioral interactions might play acceptance hosts. found improved suppression under high-water limitation, but underlying mechanisms were different. Mild-stress appeared maximize as indicated by highest mummy production. Aphids larger when feeding plants than any other treatment, suggests parasitoids. Improved high-stress may been driven enhanced nonconsumptive effects. Despite suppression, formation was lowest plants. High-stress conditions shown negatively affect so be poor performance exacerbating cost with parasitoids, such stinging. No differences observed foraging behaviors antennation stinging across treatments. highlights importance stress intensity affecting outcomes parasitoid–host