Functional Responses of Three Insect Predators to Plutella xylostella Across Developmental Stages

The diamondback moth, Plutella xylostella, is a major pest of cruciferous crops, and predatory insects are important candidates for its biological control. However, predator performance may vary substantially across developmental stages, complicating stage-specific evaluation and cross-species comparison. Here, we quantified corrected prey consumption and functional response patterns of three insect predators, Eocanthecona furcellata, Hierodula patellifera, and Paratenodera sinensis, across predator developmental stages, prey stages, and prey densities under laboratory conditions. Functional response types were classified using logistic regression, and model parameters were estimated using nonlinear functional response models. Corrected prey consumption generally increased with prey density, but the strength of density-dependent differentiation varied among predator instars and prey stages, with clearer treatment separation typically observed in later instars and adults than in early instars. Across 37 predator–prey-stage combinations, Type II-like functional responses predominated in 29 combinations, whereas 6 were classified as Type III-like and 2 were ambiguous. Strict matched-subset analysis further showed that relative differences among predator species were stage-dependent, indicating that cross-species comparisons were sensitive to predator developmental stage and the degree of experimental matching. These results indicate that the three predators have stage-dependent potential for the biological control of P. xylostella and provide a laboratory-based basis for their future evaluation and application under field conditions.