Flooding: another abiotic stressor to consider in plant-insect interactions

Flooding is an increasingly important plant abiotic stress that is intensifying with climate change, yet its ecological implications, particularly for plant- insect interactions remain poorly understood and synthesized. Both flooding and after-flood recovery period disrupt plant growth, physiology, metabolism and biochemistry. Although plant responses to flooding have been extensively studied, the mechanistic links connecting these flooding and after-flood phase induced changes to insect herbivore performance and behavior remain largely unresolved. In this review, we synthesize current knowledge on the pathways through which flooding could potentially re-shape plant-insect interactions. We highlight several interconnected mechanisms, including flooding-induced changes in plant physiology and nutrient status, shifts in phytohormone signaling and plant changes during after-flood recovery phase. These flooding-induced changes can affect insect herbivore growth, performance, oviposition, interactions with natural enemies and ultimately pest outbreaks. Our synthesis reveals that although some individual mechanisms have been documented, the links connecting flooding-induced plant responses to insect outcomes remain largely unresolved. While more foundational evidence regarding flooding-plant-insect interactions is needed, available studies suggest that flooding should be considered as a multi-pathway stress that can reorganize plant metabolic, chemical and nutritional landscape triggering cascading ecological consequences across diverse herbivore guilds. Addressing these gaps will require integrative approaches and will provide a foundation for developing new testable plant- insect interaction hypotheses and advancing ecological theories under changing environmental conditions.