Dupont_2025_Environ.Res__123332

Pesticides are mainly used in agroecosystems to control pests. Due to their limited specificity, the resulting widespread contamination may cause unintended effects on non-target organisms that use these habitats. While increasing attention is paid to the relationship between single substances and phenotype on non-target species, their combined impacts are still largely unknown. Since interactions between pesticides may also impact organisms' health, studying them as complex mixtures is the more realistic approach. Here, we present the first experimental study testing the relationship between an environmentally relevant pesticide mixture and health biomarkers on a farmland avian non-target model. To do so, we used 40 semi-captive grey partridges (Perdix perdix) fed for five months with conventional grains. Their plant protection product (PPP) load (i.e., the number of PPPs, the total sum of scaled pesticide concentrations and the total toxicity index) in blood and proxies of health status (evaluated using behavioral and physiological features) were monitored at the end of the exposure period. We demonstrated, for the first time, concerning correlations between PPP load indexes and bird health-related features (physical activity, flight initiation distance, eye ring redness and acetylcholinesterase activity). Overall, we highlighted the urgent need to consider environmentally-relevant PPP mixture when biomonitoring non-target vertebrates in ecotoxicological studies.