Functional response of Chrysoperla carnea and Coccinella septempunctata against Spodoptera frugiperda

Abstract

The Fall Armyworm (Spodoptera frugiperda) is a highly invasive pest that threatens global food security by causing significant yield losses in maize (Zea mays L.) and other cereal crops. To address this challenge through sustainable pest management, this study evaluates the predatory potential and functional response of two biocontrol agents, third-instar larvae of the green lacewing (Chrysoperla carnea) and adults of the seven-spotted ladybird beetle (Coccinella septempunctata), against early-instar S. frugiperda larvae. Experiments were conducted under controlled laboratory conditions, exposing individual predators to varying prey densities (2–40 larvae). Both predators exhibited a Type II functional response, characterized by an initial rapid increase in prey consumption that plateaus due to satiation and handling time constraints. Quantitative analysis revealed that C. carnea displayed superior predatory efficiency, with a higher attack rate (a = 0.421 h⁻¹) and shorter handling time (Tₕ = 0.25 h) compared to C. septempunctata (a = 0.315 h⁻¹, Tₕ = 0.38 h). Consequently, C. carnea achieved a maximum theoretical predation rate of 40 larvae/day, while C. septempunctata reached 26 larvae/day. However, C. septempunctata adults showed a higher predation rate on first- and second-instar S. frugiperda larvae compared to its own third- and fourth-instar larvae, with attack rates of 0.0496–0.0821 h⁻¹ and handling times of 0.0496–0.0915 h⁻¹. In contrast, C. carnea third-instar larvae outperformed second-instar larvae, with attack rates of 0.96–1.11 day⁻¹ and handling times of 0.10–0.14 day⁻¹. These findings highlight the significant predatory capacity of both species, with C. carnea emerging as a particularly effective candidate for augmentative biological control within Integrated Pest Management (IPM) programs for S. frugiperda, offering an environmentally sustainable alternative to chemical insecticides.