Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non-crop habitats, and species' dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7-and 1.4-fold respectively. Arable-dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services.

International audienceIn agrosystems, the increase in non-crop plant diversity by habitat management in or around arable fields contributes to improved Conservation Biological Control. During winter, plant flower are often used as monospecific ground cover and are expected to die before flowering as a result of recurrent frost events. Decreases in minimal temperature due to climate change offers new possibilities for plants used in such sown cover crops to mature and flowers. Changes in plant phenology thus constitute an important environmental change with expected consequences for ecosystem functioning, such as biological control. In Brittany, where winter agricultural landscape is dominated by a mosaic of cereal and sown cover crops, we assessed the consequences of mustard (Synapis alba) flowering cover crops (MFCC) on aphid parasitism and food web structure in plots adjoining cereal crops, in contrast to plots close to spontaneous non-crop plants (SNCP) of the same field. Overall, aphid parasitism rate at the field scale was strong (60–70%), being 13% higher adjacent to the MFCC than closer to SNCP. In addition, there was no change in food web structure between the two distinct zones, enabling us to hypothesize that MFCC mostly constituted an alimentary patch. The positive effect on parasitism rate was significant but weak, as floral nectar of mustard is known to be of poor quality for parasitoids. Results highlight the potential advantages of adapting practices in response to actual changes in agrosystems. Increase floral diversity in sown cover crops could constitute a complementary method in management programs, by providing more alternative food resources, alternative hosts, and climatic refuge to enhance the Conservation Biological Control of parasitoid populations

International audience1 We investigated, over the course of 2 years, the spatial distribution and abundance of two species of aphid, Metopolophium dirhodum and Sitobion avenae, and predatory species of carabid. This was undertaken in 24 wheat fields in 'coarse-grain' and 'finegrain' landscapes in western France. A greater percentage of the latter landscape was covered by hedgerows and grassland and the total area covered by fields and the average size of the fields were smaller. 2 The effects on aphid abundance of the distance from field margins, the presence of grassy strips and carabid abundance were determined in both landscapes. 3 Both aphid species were more abundant in the 'fine-grain' landscape, which may have been a result of the higher density of semi-natural elements. In both types of landscape, the total numbers of aphids were negatively correlated with the distance from the field margin. This may have been because aphids were dispersing from overwintering sites in field margins. The abundance of M. dirhodum was strongly negatively correlated with the presence of grassy strips in the 'coarsegrain' landscape, although there were no such significant correlations for either of the aphid species in the 'fine-grain' landscape. 4 Aphid and carabid abundances were negatively correlated in the 'fine-grain' and positively in 'coarse-grain' landscape. 5 The results obtained in the present study emphasize the importance of semi-natural areas in agricultural landscapes in shaping the spatial distribution of aphids and carabid beetles, their natural enemies, at different spatial scales

International audienceContext: The importance of landscape complexity for biological control is well-known, but its functional roles are poorly understood.Objectives: We evaluated the landscape capacity to provide floral resources for beneficial insects and its consequences for biological control in fields.Methods:The gut contents of adult hoverflies sampled in 41 cereal fields were analysed to determine which plant species are exploited. The relative value of each habitat in providing adequate pollen resources was evaluated by vegetation survey. Then 15 cereal fields were selected along a gradient of landscape complexity, where the abundance of aphids, hoverfly larvae and aphid parasitism was monitored. The habitat’s proportions in landscape buffers surrounding these fields were used as landscape descriptors and to assess the potential level of pollen resources provision (LP index).Results: Aphid abundance significantly decreased with an increase of the LP index mainly sustained by grassy strips and weeds in fields. However, hoverfly larvae abundance also decreased with the increasing LP index. The enhancement of the aphid parasitism rate with the LP index suggests that aphid parasitoids may benefit from the same floral resources as hoverflies. Their crop habitat specialism may give them a competitive advantage in fields where both aphid and floral resources are abundant.Conclusions: Complex interaction networks involved in biological control may disrupt the expected direct effects of floral resource provisioning for a focal beneficial species. We highlighted fields and grassy strips as habitats provisioning floral resources for which the LP index could be very helpful to optimize agroecological management strategies