Insect-eating animals in arable farming: diversity, ecosystem services and habitat potential

The CAS DAR project ‘Insect-eating organisms in arable farming: diversity, ecosystem services and habitat potential’ ran from 2009 to 2011, led by ARVALIS-Institut du végétal. This project forms part of efforts to assess biodiversity in agricultural environments and to reduce the use of plant protection products. It focuses in particular on the insect-eating Carabidae and Syrphidae families and aims to assess 1) the contribution of arable crops to maintaining the diversity of these families, 2) the effect of agricultural practices and land management on these species, 3) their role in regulating pest populations across different landscape contexts. To achieve these objectives, various experiments were set up in three arable farming regions (Rhône-Alpes, Centre–Île-de-France, Picardy). Forty-five plots spread across 11 different landscapes were monitored using Barber traps, emergence traps, funnel traps and Malayan tents. This represents over 21,000 records for ground-dwelling fauna and 9,000 for flying fauna. Numerous findings were obtained, highlighting the diversity of species encountered in arable farming environments and the effect of agricultural practices or land management on these different communities. The ‘production’ of beneficial insects can be ensured by a mosaic of crops, with semi-natural habitats ensuring the sustainability of populations. Innovative experiments to assess the services provided by Carabidae and Syrphidae were conducted in parallel. To address this issue, field and laboratory experiments were carried out, providing an initial approach to evaluating the services rendered by beneficial insects. Finally, decision-support tools were proposed to estimate the entomophagous potential – specifically that of ground beetles and hoverflies – on a farm, with a view to conserving and enhancing it.