Insect quantity is an important index for determining the degree of damage to plants. The brown planthopper (BPH), Nilaparvata lugens (Stål), is one of the most important rice pests in Asia. Here, we used two genotypes of BPH, a high-fecundity genotype (HFG) and a low-fecundity genotype (LFG), to measure their ecological fitness and to explore possible causes for genotype differentiation by transcriptome sequencing. Our results showed that there were significant differences in body weight, egg hatching rate and honeydew secretion between the HFG and LFG, particularly, the number of eggs laid per female was more significant. Transcriptional analysis showed that a total of 1966 differentially expressed genes (DEGs) were mainly involved in energy metabolism, carbohydrate and lipid synthesis, insect hormone synthesis and fecundity-related pathways. Moreover, we found that the phosphorylation levels of AMPK, AKT and FoxO and the synthesis of ecdysone were different between the two genotypes of BPH. These findings may partially explain the difference in the ecological fitness between HFG and LFG. This study is the first to compare the differences between two genotypes of BPH and to provide transcriptomic evidence to further understand the fecundity of BPH.

昆虫数量是确定植物受损程度的重要指标。褐飞虱（BPH），Nilaparvata lugens（Stål）是亚洲最重要的水稻害虫之一。在这里，我们使用了BPH的两个基因型，高繁殖力基因型（HFG）和低繁殖力基因型（LFG），以测量它们的生态适应性，并通过转录组测序探索基因型分化的可能原因。我们的结果表明，HFG和LFG在体重，卵孵化率和蜜露分泌方面存在显着差异，特别是每位女性产卵的数量更为显着。转录分析表明，共有1966个差异表达基因（DEGs）主要参与能量代谢，碳水化合物和脂质合成，昆虫激素合成以及与生殖力有关的途径。此外，我们发现AMPK的磷酸化水平 两种BPH基因型之间的AKT和FoxO以及蜕皮激素的合成不同。这些发现可能部分解释了HFG和LFG在生态适应性方面的差异。这项研究是首次比较两种BPH基因型之间的差异，并提供转录组学证据以进一步了解BPH的生殖力。