Agricultural intensification and increased pesticide use reduces nocturnal insect abundance and species richness and therefore affects the foraging activity of bats, since bats are primary predators of nocturnal insects. Addtionally nocturnal insects are contaminated with pesticide residues and therefore pose a risk in oral food uptake.

Thus, in order to evaluate the possible risk that bats are facing, the European Food Safety Agency has published the “Scientific statement on the coverage of bats by the current pesticide risk assessment for birds and mammals” (EFSA, 2019). This statement reveals an existent data gap on residue unit per dose (RUD) values for flying insects, which are necessary to elaborate a proper environmental risk assessment on insectivorous bats. To calculate these RUD values, nocturnal insects need to be sampled for residue analysis. Therefore, it is necessary to find a methodology that allows an appropriate sampling of flying insects that resembles the diet of insectivorous bats.

This project aims to estimate and compare RUD values from flying insects collected with different methodologies, in order to select the most suitable methodology for the determination of fungicide residue data. Samples were collected in vineyards and an apple orchard located in South-west France during summer, by using light traps, malaise traps and car netting, to compare collection success and sampled communities but also to analyse fungicide residues. The study was carried out in collaboration with Eurofins-Mitox.