Red Light Increases the Crawling Distance of Arma Chinensis and Halyomorpha halys and Their Visual Protein Identification

Phototactic behavior is critical for insect ecological adaptation, especially visual responses to light wavelengths. This study examined locomotor responses to red and ultraviolet (UV) light in congeneric pentatomids, a predator ( Arma chinensis ) versus a pest ( Halyomorpha halys ), and explored the underlying visual molecular mechanisms. Results showed that red and UV light significantly increased total movement distance of both species with distinct species—and sex‐specific differences. Red light exerted the strongest promoting effect on total movement distance, particularly during 4–8 h of exposure. Male A. chinensis traveled farther, moved faster, and paused more frequently than females under red and UV light. Male H. halys moved faster and paused more frequently under red light; H. halys moved faster than A. chinensis under red light, while female H. halys had longer pause duration than female A. chinensis under UV light. For H. halys , females traveled farther under control light, with no sex difference under red light and males traveling farther under UV light. H. halys possesses three long‐wavelength opsins versus two in A. chinensis . Both species share the conserved 7tm_photoreceptors_insect domain and typical GPCR characteristics, and their opsins are highly homologous with other Hemiptera. Although conducted under laboratory conditions, our findings provide valuable insights into the development of environmentally friendly pest control methods and open new avenues for basic and applied insect visual ecology research.