Abstract

Understanding the comparative genetic structure of aquatic insects is crucial for elucidating the evolutionary processes that shape biodiversity and for informing conservation strategies. This study investigates the genetic structure and diversity of two aquatic insect species, Klapopteryx kuscheli (Plecoptera) and Andesiops torrens (Ephemeroptera), across Argentinean Patagonia. Using mitochondrial and nuclear genetic markers (COX1, 18S, 16S, and H3), we analyzed specimens from 37 sites spanning their latitudinal range, aiming to understand the historical and contemporary factors shaping their genetic makeup, focusing on dispersal potential and speciation. Our results reveal significant genetic divergence among K. kuscheli populations, particularly in northern Patagonia, where higher haplotype diversity was observed. This diversity likely stems from historical glacial refugia during the Pleistocene together with their limited dispersal capabilities, which possibly contribute to this pronounced genetic structuring by restricting gene flow between populations. Conversely, A. torrens exhibited less divergent geographic genetic structure, consistent with its higher dispersal ability, where it exhibited two distinct groups not linked to sampling locations, suggesting that they may have had a different evolutionary history or a recent speciation event among populations. Our findings enhance the understanding of microevolutionary processes shaping genetic diversity in Patagonian aquatic insects. Preserving genetic variation is crucial for species' long-term resilience.