Biological Control Potential of the Reduviid Predator Rhynocoris fuscipes (Fabricius) in Managing Noctuid Pests: Insights Into Predation and Prey Preference

Understanding predator-prey and predator-predator interactions is essential for evaluating the effectiveness of biocontrol agents and developing efficient pest management strategies. This study investigates the effects of prey species, predator life stage, and predator density on the predatory efficiency of the generalist predator <i>Rhynocoris fuscipes</i> (Fabricius) under semi-field conditions. Both the nymphs and adults of <i>R. fuscipes</i> consumed significantly more second-instar larvae of <i>S. frugiperda</i> than larvae of <i>S. litura</i> or <i>M. separata</i>. Notably, fifth-instar nymphs and adults exhibited higher predation capacity (11.75 ± 0.37 and 10.90 ± 0.40 larvae) than fourth-instar nymphs (9.05 ± 0.29 larvae) on <i>S. frugiperda</i>. <i>R. fuscipes</i> demonstrated a Type II functional response at all developmental stages toward each prey species, and fifth-instar nymphs revealed higher attack rates (<i>a</i> = 1.5205 ± 0.0544) on <i>S. frugiperda</i>; additionally, the handling time did not significantly differ among three prey species. It suggests that this predator may be more effective at controlling noctuid populations at low prey densities. As predator age and density increased, intraspecific competition among <i>R. fuscipes</i> also intensified. In a multi-prey system, <i>R. fuscipes</i> showed a marked preference for <i>S. frugiperda</i> over the other two prey species. These findings indicate that the fifth-instar nymphs and adults of <i>R. fuscipes</i> are particularly effective in suppressing early-instar larvae of the three noctuid pests, especially <i>S. frugiperda</i>, at low densities. This study enhances our understanding of the predation capacity and prey preference of <i>R. fuscipes</i> towards the three noctuid pests and provides a foundation for the development of more targeted and efficient pest management strategies using this predator.