Predation functional response and demographic parameters of Orius albidipennis (Hemiptera: Anthocoridae) on Schizaphis graminum (Hemiptera: Aphididae): effect of host plant morphological attributes

Abstract

ABSTRACT Plant morphological attributes diversely affect the biocontrol agents of phytophagous insects. In the current study, the effect of physical plant features on life table characteristics and functional response of Orius albidipennis (Rueter) females feeding on Schizaphis graminum (Rondani) was investigated on two common wheat cultivars (Falat and Pishtaz) differing in leaf morphological features. The trichome density considerably influenced a broad spectrum of attributes related to the performance of O. albidipennis. Although Orius predators exhibited type III of functional response on both cultivars, they had lesser searching efficiency and higher handling time on Pishtaz than on Falat cultivar. The maximum attack rate was greater on Falat than on Pishtaz. Lesser maximum predation and greater handling time of the Orius predators on Pishtaz might be imputed to the significantly more condensed surface trichomes of its leaves than that of Falat leaves, which physically prevented movement of the bugs and decreased prey encounter rate. Moreover, an increase in trichome density negatively influenced the foraging behaviour of the predatory bug. Females were also found to prefer leaves with fewer trichomes as oviposition hosts. It seems that trichomes provided hindrance to the Orius bug. The intrinsic rate of increase (rm) was significantly greater on Falat than on Pishtaz cultivar. Similarly, the net reproductive rate and finite rate of increase were greater on Falat than on Pishtaz. To recapitulate, it could be stated that the efficiency of O. albidipennis in controlling S. graminum on wheat may be more beneficial in cultivars with lower trichome density.