Using instruments in the study of animate beings:Della Porta’s and Bacon’s experiments with plants

In this paper, I explain Francis Bacon's use of plants as philosophical instruments in the context of his Historia vitae et mortis. My main claim is that Bacon experimented with plants in order to obtain knowledge about the hidden processes of nature, knowledge that could be transferred to the human case and used for the prolongation of life. Bacon's experiments were based on Giambattista della Porta's reports from the Magia naturalis, but I show how a different metaphysics and research method made Bacon systematically rework, reconceptualise, and put to divergent uses the results of the same experimental reports

Predatory efficacy of Dicyphus errans on different prey

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

Functional response of the mirid predators Dicyphus bolivari and Dicyphus errans and their efficacy as biological control agents of Tuta absoluta on tomato

Dicyphus bolivari Lindberg and Dicyphus errans (Wolff) (Hemiptera: Miridae) are naturally widespread in many crops with low-pesticide pressure, where they prey upon several arthropods, including the tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). However, their efficacy as biological control agents (BCAs) of this pest needs further investigations. Therefore, in this study the predatory efficacy of D. bolivari and of D. errans on T. absoluta was evaluated on tomato in laboratory and greenhouse trials. Their functional response to different numbers of T. absoluta eggs (up to 350) offered to single females or 5th-instar nymphs for 24 h was assessed in laboratory. Females and nymphs of both predators showed a high voracity and a type II functional response, with an estimated maximum predation rate per day of 189 and 194 eggs for D. bolivari females and nymphs, respectively, and 197 and 179 eggs for D. errans females and nymphs, respectively. The predators showed similar predation rates of T. absoluta eggs on plants in cage trials. However, our greenhouse trial showed that the commonly used Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae), which has a lower individual predation capacity than D. bolivari and D. errans, was more effective in controlling T. absoluta than D. errans and D. bolivari because of its stronger numerical response to densities of T. absoluta and supplemental food than the other two predator species. This shows that long-term greenhouse trials, which include functional and numerical responses to pest densities, are essential to evaluate the efficacy of an omnivorous predator.</p