Landscape context influences leafhopper and predatory Orius spp. abundances in maize fields
2018
Ardanuy, Agnès | Lee, Marina S. | Albajes, R. (Ramon)
Biological control relies on the periodical colonization of crops by natural enemies from surrounding habitats. In North‐East Spain, predatory Orius spp. disperse among cereal, maize and alfalfa according to crop phenology and management. In the present study, we examined (i) the variation of Orius spp. and its leafhopper prey Zyginidia scutellaris populations in co‐occurring habitats (maize, alfalfa and semi‐natural) for 2 years in three regions and (ii) the effects of agricultural landscape context on their abundance in maize. Variance partitioning revealed that inter‐annual variation accounted for the largest proportion of variation for Orius spp. and its prey. Maize leafhopper abundance was positively related to winter cereal cover in the landscape and negatively related to semi‐natural habitat across the three regions. Orius spp. were unresponsive to shifts in habitat composition despite being present in maize and associated habitats; however, they were positively related to edge density. Larger‐scale variation in Orius spp. abundance was best explained by changes in Z. scutellaris abundance in maize. Leafhopper colonization is responsible for the recruitment of Orius spp. in maize. Orius spp. conservation in intensive agricultural landscapes might require permanent field margins and complementary crops (e.g. alfalfa) that ensure resource continuity in time.
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