Data from: Transgenerational effects modulate density-dependent prophylactic resistance to viral infection in a lepidopteran pest

There is an increasing appreciation of the importance of transgenerational effects on offspring fitness, including in relation to immune function and disease resistance. Here, we assess the impact of parental rearing density on offspring resistance to viral challenge in an insect species expressing density-dependent prophylaxis (DDP); i.e. the adaptive increase in resistance or tolerance to pathogen infection in response to crowding. We quantified survival rates in larvae of the cotton leafworm (Spodoptera littoralis) from either gregarious- or solitary-reared parents following challenge with the baculovirus S. littoralis nucleopolyhedrovirus. Larvae from both the parental and offspring generations exhibited DDP, with gregarious-reared larvae having higher survival rates post-challenge than solitary-reared larvae. Within each of these categories, however, survival following infection was lower in those larvae from gregarious-reared parents than those from solitary-reared, consistent with a transgenerational cost of DDP immune upregulation. This observation demonstrates that crowding influences lepidopteran disease resistance over multiple generations, with potential implications for the dynamics of host–pathogen interactions.学界对跨代效应（transgenerational effects）对子代适合度的重要性的认知正不断加深，此类效应的关联范畴涵盖免疫功能与疾病抗性。本研究针对一种表现出密度依赖性防御（density-dependent prophylaxis, DDP）的昆虫类群展开探究，其中密度依赖性防御指生物体因种群拥挤而产生的对病原体感染的抗性或耐受性的适应性提升，旨在解析亲本饲养密度对子代抵抗病毒侵染能力的影响。我们选取棉叶虫（*Spodoptera littoralis*）为研究对象，对来自群居饲养或独居饲养亲本的子代幼虫，在接种棉叶虫核型多角体病毒（*S. littoralis* nucleopolyhedrovirus）后统计其存活率。结果显示，亲本世代与子代世代的幼虫均表现出密度依赖性防御：群居饲养的幼虫在病毒侵染后的存活率显著高于独居饲养的幼虫。但在上述两类群体内部，来自群居饲养亲本的子代幼虫的感染后存活率，反而低于来自独居饲养亲本的子代幼虫，这与密度依赖性防御的免疫上调存在跨代代价的理论预期相符。该研究结果表明，种群拥挤会跨代影响鳞翅目昆虫的疾病抗性，这一发现对宿主-病原体互作的动态变化具有潜在的研究价值。