Transposable elements differ between geographic populations of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

This article investigates the variation in transposable elements (TEs)—mobile DNA sequences—in geographic populations of the Colorado potato beetle, *Leptinotarsa decemlineata*, to understand their potential role in rapid adaptation, including insecticide resistance. Analyzing 88 resequenced beetle genomes from North America, the study found that Mexican beetles harbor a higher abundance of TEs than U.S. beetles, but TE diversity did not differ significantly by geography, host plant (potato vs. buffalo bur), or imidacloprid insecticide resistance. Principal Components Analysis of TE insertion sites revealed population structure consistent with known genetic differentiation, yet TE insertions contributing most to population differences were located in noncoding genomic regions without annotated genes linked to resistance. Overall, while TE abundance and diversity vary among populations and reflect demographic history, the study did not find direct evidence that TE activity correlates with the beetle’s major adaptive traits such as host expansion or insecticide resistance.