Abundance, movements and biodiversity of flying predatory insects in crop and non-crop agroecosystems

[EN] Predatory insects are key natural enemies that can highly reduce crops pest damage. However, there is a lack of knowledge about the movements of flying predatory insects in agroecosystems throughout the year. In particular, it is still unclear how these predators move from crop to non-crop habitats, which are the preferred habitats to overwinter and to spread during the spring and if these predators leave or stay after chemical treatments. Here, the Neuroptera, a generalist, highly mobile, flying predator order of insects, was selected as model. We studied the effects of farming management and the efficiency of edge shelterbelts, ground cover vegetation, and fruit trees canopy on holding flying predatory insects in Mediterranean traditional agroecosystems. Seasonal movements and winter effects were also assessed. We evaluated monthly nine fruit agroecosystems, six organic, and three pesticides sprayed, of 0.5-1 ha in eastern Spain during 3 years using two complementary methods, yellow sticky traps and aspirator. Results show surprisingly that the insect abundance was highest in pesticide sprayed systems, with 3.40 insects/sample versus 2.32 insects/sample in organic systems. The biodiversity indices were highest in agroecosystems conducted under organic management, with S of 4.68 and D of 2.34. Shelterbelts showed highest biodiversity indices, S of 3.27 and D of 1.93, among insect habitats. Insect species whose adults were active during the winter preferred fruit trees to spend all year round. However, numerous species moved from fruit trees to shelterbelts to overwinter and dispersed into the orchard during the following spring. The ground cover vegetation showed statistically much lower attractiveness for flying predatory insects than other habitats. 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Effects of Organic and Conventional Cultivation on Composition and Characterization of Two Citrus Varieties ‘Navelina’ Orange and ‘Clemenules’ Mandarin Fruits in a Long-Term Study

A transition towards an organic food system is taking place around the world. This process is favored by growing consumer demand, who associate organic crops with being healthier, tastier, and safer for the environment than conventional crops. Citrus is one of the most widely produced crops worldwide and has important socio-economic and cultural significance in the Mediterranean area. The aim of this work is twofold; on the one hand, it reveals the variability of a set of physical–chemical and nutritional quality parameters of two citrus fruit varieties, ‘Navelina’ oranges and ‘Clemenules’ mandarins, from organic and conventional production in a long-term study. On the other hand, taking advantage of the large number of results, a model is proposed that allows the successful differentiation of citrus fruits from organic and conventional production and a tool that allows predicting the production system of citrus fruits. The results suggest that organically produced citrus fruits do not generate differences in terms of external aspects, providing fruits that are acceptable to the market. Organic production techniques influenced the lower peel content and higher pulp and juice content in ‘Navelina’ orange and ‘Clemenules’ mandarin fruits and led to a greater ability to synthesize vitamin C in the juice, more essential oils in the skin, and higher seed numbers, although in all cases, the fruits can be classified as having low seed numbers. Two discriminating equations were obtained that use easy-to-measure parameters to successfully classify organic citrus fruits. The classification and prediction models obtained constitute useful tools to help in the control of the purity/authenticity of organic citrus fruits