An ovary‐enriched lipase gene, LOC118266188 , is required for embryonic development and female fertility in Spodoptera frugiperda

BACKGROUND The regulatory functions of ovary‐enriched genes in female reproduction are well characterized in model insects, but remain largely unexplored in agricultural pests such as the fall armyworm (FAW), Spodoptera frugiperda . This study aimed to identify ovary‐enriched genes in FAW and characterize their roles in female reproduction. RESULTS Transcriptomic analysis identified more than 3000 genes upregulated in adult ovaries. Among these, a lipase‐encoding gene, LOC118266188 , exhibited the highest ovarian expression. Quantitative real‐time polymerase chain reaction analysis revealed that LOC118266188 transcript levels surged before eclosion and remained elevated in adults. Using CRISPR/Cas9, we generated a homozygous LOC118266188 knockout line. Mutant females produced normal egg numbers with no obvious ovarian defects, but the egg hatching rate (32.70%) was dramatically reduced compared with wild‐type (87.05%). Time‐course observation revealed that mutant embryos were arrested between 24 and 36 h post‐oviposition. Transcriptomic analysis showed that downregulated genes in mutant ovaries were enriched in lipid metabolism pathways. CONCLUSION These findings demonstrate that LOC118266188 is essential for female fertility in FAW, likely through its association with lipid metabolism. This study provides new molecular insights into insect reproduction and identifies LOC118266188 as a potential target for genetic pest control.