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 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, in the parent or F1 generations when exposed to predation risk of a caged predator, Paederus fuscipes. We also uncovered the survival outcomes (fitness gained) in SBPHs with predator-induced defensive morphological traits by examining their survival probability and behavioral plasticity. Results showed risky predators 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, probably because females suffered greater mortality than males during the longer periods of predation risk. Surprisingly, we discovered these long-winged forms had a higher survival probability 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 may illuminate the context of ecosystem evolution, help to predict pest dispersal or migration, which contributes to pest control.

Data 1:

The data of proportion of macropters and surviving SBPHs (small brown planthoppers) were collected by exposing different instar nymphs of SBPHs to predation risk of rove beetle Paederus fuscipes. When these nymphs had developed into adults, we counted the number of macropters, brachypters, and total surviving number of SBPHs and calculated the proportion of macropters and surviving SBPHs respectively.

Data 2:

The data of number of attacks and time taken were collected by putting threatened or non-threatened macropters to a peri dish with starved predator and counted the number of attacks and time needed for predator to successfully capture threatened or non-threatened macropter.