Predator-cue induced plasticity of defensive morphology and behavior in planthoppers facilitate the survival from predation

Predators can induce morphological plasticity in prey through selection driven by predation risk. However, defense plasticity is rarely reported in insects, let alone trans-generational plasticity, the underlying mechanisms and attention of such plasticity devoted to pest control and ecosystem evolution. Here we examined the morphological plasticity of small brown planthoppers (SBPHs), Laodelphax striatellus, elicited by caged predators, Paederus fuscipes in the parent or F1 generations and uncover the risk cues mediating these effects. We also uncovered the survival outcomes in SBPHs with predator-induced defensive morphological traits by examining their survival probability and behavioral plasticity. Results showed caged predators or predator odor cue could enhance a higher proportion of long-winged, female SBPHs in the parent and F1 generation, but the proportion of males neither short- nor long- winged forms were affected. The visual cue from predators elicited weaker effects. Surprisingly, we discovered these long-winged forms suffer a lower predation rate when attacked by P. fuscipes, owing to an enhanced agility level. Our results suggest the within- and trans-generational plasticity of induced defenses may cause profound effects on SBPH population dynamics and prey-predator interaction. Understanding this interaction and mechanisms may illuminate the context of ecosystem evolution, help to predict pest dispersal or migration, which contributes to pest control.