Inherited predation defense strategies in planthopper: Implications for biocontrol and ecosystem evolution

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), <i>Laodelphax striatellus</i>, elicited by caged predators, <i>Paederus fuscipes</i> 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 <i>P. fuscipes, </i>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.

捕食者可通过捕食风险介导的选择作用，诱导猎物产生形态可塑性。然而，昆虫中的防御可塑性鲜有报道，跨代可塑性更是如此，且这类可塑性在害虫防治与生态系统演化中的相关机制与研究关注度仍有待阐明。本研究针对灰飞虱（small brown planthoppers, SBPHs，学名Laodelphax striatellus）展开实验，考察了亲本及F1代中，笼养天敌青翅蚁形隐翅虫（Paederus fuscipes）诱导产生的形态可塑性，并解析介导该效应的风险信号。此外，本研究通过检测灰飞虱的存活概率与行为可塑性，明确了携带捕食者诱导的防御形态特征的灰飞虱的存活表现。结果显示，笼养天敌或天敌气味信号可提升亲本及F1代中长翅型雌虫的占比，但无论短翅型还是长翅型雄虫的比例均未受显著影响。天敌的视觉信号仅产生较弱的效应。值得注意的是，本研究发现，由于机动性提升，这类长翅型个体在遭遇青翅蚁形隐翅虫（Paederus fuscipes）捕食时的被捕食率更低。本研究结果表明，诱导型防御的当代及跨代可塑性可能对灰飞虱种群动态以及猎物-捕食者互作产生深远影响。阐明这类互作关系与相关机制，有助于解析生态系统演化的相关背景，预测害虫的扩散与迁飞规律，进而为害虫防治工作提供理论支撑。