miR-8 modulates reproductive and tissue homeostasis traits in Arma chinensis Fallou: a new insight to improve biological control

Arma chinensis Fallou (Hemiptera: Pentatomidae) is a critical biocontrol agent for agricultural pests. Yet its efficacy is constrained by susceptibility to pathogens and suboptimal breeding conditions. It has been previously demonstrated that miR-8 and Toll family regulate host immunity. However, the physiological damage of miR-8 overexpression and Toll knockdown on A. chinensis is still unknown. This study reveals associations of miR‑8 and Toll receptors with tissue integrity and neural morphological development in A. chinensis. Through paraffin sectioning and RNA interference, we demonstrate that Toll receptors are critical for ovarian/testicular development, midgut barrier integrity, and fat body adhesion. Furthermore, interference with specific Toll receptors disrupted nerve cell distribution and adhesion in the brain. miR-8 over-expression was associated with reduced transcript levels of fas2 and nlg4, as well as with neuronal adhesion defects and reduced optic lobe volume, suggesting a potential transcriptional and morphological link to neural structure. These findings suggest a miR-8-Toll axis that is associated with tissue homeostasis and neural connectivity in A. chinensis, providing a foundation for understanding Hemiptera-specific developmental mechanisms and offering strategies to optimize biocontrol agent durability and reproductive output.