Small-scale population structuring results in differential susceptibility to pesticide exposure

Abstract Central European riverine networks are subject to widely varying local anthropogenic pressures, forcing species with limited dispersal abilities adapt or become locally extinct. Previous catchment-wide studies have shown that some invertebrates tend pronounced population structuring throughout mountainous river networks, raising the question of whether this also translates into small-scale phenotypic differentiation and adaptation stressors. One such is headwater crustacean Gammarus fossarum clade 11 (or lineage B), which we restudied in terms structure four years after first assessment. Our aim was not only document temporal stability/dynamics structure, but asked a genetic results different susceptibility commonly applied pesticide. Therefore, re-assessed based on COI haplotypes their frequencies, quantified key parameters related morphological life-history differentiation. Furthermore, examined difference sensitivity towards pyrethroid insecticide deltamethrin. haplotype patterns were found be stable over time confirmed within catchment, isolated populations connected downstream populations. While little observed, marked differences found. Populations from pristine sites responded significantly more tolerant than anthropogenically impacted sites—showing prior exposure spectrum stressors does automatically increase tolerance specific stressor. our study demonstrates capacity reflected variation disturbance. The system thus provides suitable experimental landscape test impact further (e.g., other novel entities, including pesticides modes action) Based these findings, important recommendations for protection intraspecific can developed.