Mechanisms Underlying Male Reproductive Toxicity Induced by Sublethal β-Cypermethrin Exposure in Antheraea pernyi...

Pyrethroid insecticides are widely used in agriculture, but their sublethal effects on male reproduction in Antheraea pernyi (Guérin-Méneville, 1855) (Saturniidae) remain largely unknown. Here, we evaluated the effects of sublethal β-cypermethrin exposure (LC₂₀ = 0.0074 mg/L) on gonadal development, testicular morphology, sperm quantity and function, mating behavior, and post-mating egg traits from the larval to adult stages and investigated the molecular mechanisms using transcriptome sequencing. Insecticide stress impaired testicular development and disrupted spermatogenesis, leading to a 25% reduction in eupyrene sperm bundles, a 10.72% decrease in acrosin activity, and a 16.75% decrease in the curvilinear velocity of apyrene sperm. Mating willingness decreased by 17.78 percentage points, and females mated with treated males produced 20.45% fewer eggs. Transcriptome analysis identified 1193 differentially expressed genes (|log₂FC| > 1, FDR < 0.01). Detoxification and stress response genes (e.g., CYP3A27, GSTD1, ABCB1, and Hsp70) were predominantly up-regulated, while reproduction-related genes (e.g., dnal1, tubb1, ATPsynbeta, far1, JHAMT, mei-41, and dna2) were down-regulated. This study demonstrates that sublethal β-cypermethrin exposure induces male reproductive toxicity in A. pernyi through a "dual-hit" mechanism: persistently activating the detoxification system (leading to energy depletion) while directly suppressing reproductive genes, ultimately resulting in impaired germ cell development, defective sperm function, and reduced fertility.