What type of hedgerows do Brown hairstreak ( Thecla betulae L.) butterflies prefer? Implications for European agricultural landscape conservation

.  1. Agricultural intensification is the main driver of global biodiversity loss. Agri‐environment schemes (AES) are policy tools to counter this, but they need to be made more effective. 2. Here, we focus on the resource quality of hedgerows and woodland edges, which are widespread elements of most agricultural landscapes in Europe. We analyse a set of structural factors and assess their relative importance for the Brown hairstreak butterfly. This species suffered severe declines because of agricultural intensification that may be indicative of changes for other widespread insect species that use hedgerows as resources. 3. Egg‐deposition preferences were assessed by comparing egg densities among hostplant sections in two study landscapes. All sections were systematically searched during four consecutive years, resulting in 745 observed eggs. 4. We demonstrate that the ground plan outline and aspect of landscape elements, the relative position within landscape elements, and the amount of young hostplant growth are particularly relevant in explaining observed egg densities, and we link their importance with the butterfly’s behavioural biology. 5. Our study provides evidence that management focused on providing ample young growth, and transforming the landscape element ground plan outline from linear to a scalloped pattern, would benefit ectothermic species by providing more sheltered micro‐climates when they use these structural resources for breeding, feeding and moving through typically exposed agricultural landscapes. We believe that integrating such management options within general AES would translate into effective, large‐scale conservation measures for Brown hairstreaks and other species alike.