Predatory functional response of Arma chinensis (Hemiptera: Pentatomidae) to Spodoptera frugiperda (Lepidoptera:...

The invasive fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), poses a significant threat to China's agricultural sector, necessitating sustainable biological control strategies. The generalist predatory stink bug, Arma chinensis (Fallou) (Hemiptera: Pentatomidae), shows potential for controlling S. frugiperda, but the temperature-dependent efficacy is unclear. We evaluated the functional response of adult female A. chinensis to 3rd instar S. frugiperda across five temperatures (18, 23, 28, 33, and 38 °C) and five prey densities (10, 20, 30, 40, and 50 larvae per dish) under laboratory conditions. Logistic regression and model fitting via maximum likelihood estimation confirmed a consistent type II functional response at all temperatures. Temperature significantly modulated predation efficiency, with peak performance at 28 to 33 °C, characterized by the highest attack rate (0.064 to 0.067 h-1) and shortest handling time (0.918 to 0.942 h). Supra-optimal temperature (18 and 38 °C) increased handling time and reduced predation capacity, suggesting that temperature significantly modulates predation performance. The field experiment demonstrated that A. chinensis significantly suppressed S. frugiperda populations under optimal temperatures, with higher efficacy at low to moderate densities, validating the inverse density-dependent predation. This study demonstrates that temperature significantly modulates the predation capacity of A. chinensis, and identifies 28 to 33 °C as the optimal thermal range for predation on S. frugiperda larvae.