The ability of lacewing larvae to predate two pest caterpillars in relation to the prey defensive behaviour and body size

Abstract Predatory larvae of the lacewing Chrysoperla carnea (Neuroptera: Chrysopidae) represent an important biocontrol agent, as they prey on a wide range of prey, including economically important crop pests. However, some prey use active defensive behaviours that may reduce the effectiveness of these predators in biological control. In this study, we aimed to investigate the anti‐predator defensive behaviour of two economically important pests, Scrobipalpa cf. ocellatella and Autographa cf. gamma (Lepidoptera: Gelechiidae and Noctuidae, respectively), and the effectiveness of this behaviour in combination with their body size. During our laboratory experiments, the caterpillars of these species defended themselves against predators using body tremors, striking the predator with the anterior part of the body and secretion (for A. cf. gamma ) or regurgitation (for S. cf. ocellatella ). Interestingly, the defensive behaviour itself had no effect on hunting success. Instead, the killing of caterpillars depended mainly on the variance in their body size. Our results suggest that predatory lacewing larvae can be effective predators of the caterpillars S. cf. ocellatella and A. cf. gamma due to their ability to overcome their defensive behaviour. However, field experiments will be necessary to determine the effectiveness of lacewings as biocontrol agent.