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.学界日益认识到跨代效应对于后代适合度的重要意义，其中涵盖与免疫功能及疾病抗性相关的调控环节。本研究针对具备密度依赖性防御（density-dependent prophylaxis, DDP）特征的昆虫物种，探究亲本饲养密度对子代病毒攻毒抗性的影响；密度依赖性防御即宿主因种群拥挤而适应性提升对病原体感染的抗性或耐受性。本研究以棉叶夜蛾（*Spodoptera littoralis*，埃及棉夜蛾）为实验材料，分别选取亲本为群居饲养或独居饲养的幼虫，使用棉叶夜蛾核型多角体病毒（S. littoralis nucleopolyhedrovirus，隶属于杆状病毒（baculovirus）科）开展攻毒试验，并量化其存活率。结果显示，亲本代与子代幼虫均表现出密度依赖性防御特征：群居饲养的幼虫攻毒后的存活率显著高于独居饲养的幼虫。但在上述两类群体中，亲本为群居饲养的幼虫感染后的存活率均低于亲本为独居饲养的幼虫，这一发现与密度依赖性防御的免疫上调存在跨代代价的理论预期一致。该研究表明，种群拥挤可跨代影响鳞翅目昆虫的疾病抗性，这对宿主-病原体互作动态具有潜在的研究价值。