School of Life Sciences, Yunnan University, Kunming, China.
Yunnan Academy of Biodiversity, Southwest Forestry University, Kunming, China.
J Insect Sci. 2020 Jan 1;20(1). doi: 10.1093/jisesa/ieaa003.
Mating promotes reproductive activity, which may impact immune performance. Paradoxically, mating frequently challenges females' immunity (e.g., infections). Therefore, studies of postmating resource allocation between reproduction and survival are likely to shed new light on life-history trade-off and sexual selection. Here, we used RNAseq to test whether and how mating affected mRNA expression in genes related to reproduction and immunity in Spodoptera litura female moths. Results show a divergent change in the differentially expressed genes (DEGs) between reproduction and immunity: the immune response was largely downregulated shortly after mating (6 h postmating), which has some recovery at 24 h postmating; reproductive response is trivial shortly after mating (6 h postmating), but it largely upregulated at 24 h postmating (e.g., egg maturation related genes were highly upregulated). Considering the fact that most of the total DEGs downregulated from 0 to 6 h postmating (from 51/68 to 214/260) but most of the total DEGs upregulated at 24 h postmating (816/928), it is possible that trade-offs between reproduction and immunity occurred in mated females. For example, they may shut down immunity to favor sperm storage and save limited resources to support the increased energy required in reproduction (e.g., egg maturation and oviposition). Mating-induced infections should be trivial due to low polyandry in S. litura. A reduced immune defense may have no threat to S. litura survival but may benefit reproduction significantly. Furthermore, obvious expression changes were detected in genes related to hormone production, suggesting that endocrine changes could play important roles in postmating responses.
交配促进生殖活动，这可能会影响免疫表现。矛盾的是，交配经常会对雌性的免疫产生挑战（例如感染）。因此，研究交配后繁殖和生存之间的资源分配，可能会为生活史权衡和性选择提供新的见解。在这里，我们使用 RNAseq 测试了交配是否以及如何影响 Spodoptera litura 雌蛾与生殖和免疫相关的基因的 mRNA 表达。结果表明，生殖和免疫之间的差异表达基因（DEGs）呈现出不同的变化：免疫反应在交配后不久（6 小时）就被大大下调，在 24 小时后有所恢复；生殖反应在交配后不久（6 小时）几乎没有变化，但在 24 小时后则大量上调（例如，与卵子成熟相关的基因高度上调）。考虑到大多数总 DEGs 在 0 到 6 小时内下调（从 51/68 到 214/260），但大多数总 DEGs 在 24 小时后上调（816/928），因此，交配后的雌蛾可能在生殖和免疫之间存在权衡。例如，它们可能会关闭免疫以促进精子储存，并节省有限的资源来支持生殖过程中所需的能量增加（例如卵子成熟和产卵）。由于 S. litura 的多配偶制较低，交配诱导的感染应该是微不足道的。降低免疫防御可能对 S. litura 的生存没有威胁，但可能会显著有利于繁殖。此外，还检测到与激素产生相关的基因的明显表达变化，这表明内分泌变化可能在交配后反应中发挥重要作用。
