Hybridization between a native and introduced predator of Adelgidae: An unintended result of classical biological control

► We report hybridization between Laricobius nigrinus and Laricobius rubidus. ► Six microsatellite markers plus mitochondrial COI haplotypes were used. ► Introgression was widespread and asymmetrical towards L. nigrinus. ► The outcome could be a mosaic of genetic introgression across the landscape. ► Evaluating hybridization between biocontrol agents and native species is important.