Predatory efficacy ofDicyphus erranson different prey

Abstract

The Palaearctic predator Dicyphus errans (Hemiptera: Miridae) lives omnivorously on various host plants, preying on a wide range of small arthropods, including some new invasive alien species. These characteristics make it a promising biological control agent (BCA) in organic greenhouses. The capacity of a BCA to find, kill and consume prey plays a fundamental role in trophic interactions and population dynamics in a predator-prey system. The functional response of a predator, which describes how the individual rate of prey consumption changes in response to prey density, is a key component to assess its effectiveness in pest control and the stability of its own populations. Therefore, the functional response of D. errans on different prey was studied to improve our knowledge on the potential of this mirid, which is naturally widespread in European organic greenhouses. Laboratory experiments were carried out on three exotic pests: the poinsettia thrips Echinothrips americanus (Thysanoptera: Thripidae), the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), and the tomato borer Tuta absoluta (Lepidoptera: Gelechiidae), to build functional response curves. Prey was offered at different densities to single females of D. errans for 24 h. The predation behaviour of D. errans on all the prey species was defined by Type II functional response curves. The female could daily prey about 62 adults of E. americanus, 114 pupae of T. vaporariorum, and 236 eggs of T. absoluta. The high voracity of this generalist predator on different prey confirmed its suitability as a BCA. For effective and stable pest control strategies, a prior to pest establishment of D. errans in organic greenhouses may prevent pest escaping in case of high infestation rates, even if the type II functional response reaches saturation at very high prey densities.