Activités scientifiques

[E] Impact of the French Ban on Neonicotinoids : A Bee’s Eye View

Le 5 nov. 2026 de 13h00 à 14h00

Aïcha HASNI, doctorante d'Isabelle CHORT.

En visioconférence TEAMS ; en salle des thèses à Pau.

Abstract : 

This paper examines the impact of the 2018 French ban on neonicotinoids (NNI) on flower-visiting insects. We combine geolocated citizen-science data on insects from the SPIPOLL protocol over 2014–2023 with parcel-level information on agricultural land use from the French Land Parcel Information System. Exposure to the ban is the pre-ban average area of the crops potentially treated with neonicotinoids (cereals and crops attractive to pollinators) within a 500 m buffer around each observation. We exploit this heterogeneous exposure in a difference-in-differences framework, using both pooled cross-sections and a panel of revisited buffers.

Buffers neighbouring potentially treated crop parcels host more insect families. After the ban, insect family richness and abundance increase in the most exposed buffers, by about 0.44 families and one additional insect. This recovery is mainly driven by two insect orders: Hymenoptera (sawflies, wasps, bees) and Lepidoptera (butterflies and moths), and increases with exposure intensity. The results are robust to observer and plant fixed effects, alternative exposure measures and a placebo on never-treated grassland. In contrast, we find no significant recovery for bees. This may reflect slow population dynamics, the persistence of NNI in soils, continued use through derogations, or substitution with other insecticides toxic to pollinators.