Behavioral Response of a Specialist Predator, Stethorus gilvifrons (Coccinellidae: Coleoptera), to Cope with Web Structures of Four Different Spider Mite Pest Species

Abstract

The present study aimed to evaluate the web coping and attack behavior of a specialist mite predator, Stethorus gilvifrons, against the webbing structures of different spider mite pest species: Oligonychus afrasiaticus, Tetranychus urticae, Eutetranychus orientalis and O. punicae. The females of each pest species, in three different treatments, were allowed to construct web structures in the experimental arenas. The predator exhibited three different attack behaviors which were associated with the webbing life types of pest species. Against the O. afrasiaticus web, the predator used its palps and mandibles. Against the T. urticae web, the predator also made use of its first pair of legs to widen the entry hole it made by cutting. Against the O. punicae web, the predator protruded its hypognathous mouthparts to feed on mite individuals by merely entering into the web. Behavioral responses were also found to be associated with webbing life types of pests. Against O. afrasiaticus and O. punicae, the predator spent much time in web penetration and searching behaviors, respectively. The density-dependent complexity of web structure may cause hindrance to the predator, and it is suggested that adults should be released when a pest colony is growing with low webbing complexity for efficient pest management.