Genetic Evidence Reveals Unexpected Diversity and Genetic Exchange Between White-Fringed Weevils (Coleoptera, Curculionidae)

The closely related Naupactini species Naupactus leucoloma, Naupactus peregrinus, and Naupactus minor—collectively known as “white-fringed weevils”—form a monophyletic group within the N. leucoloma species group. Mostly parthenogenetic, a few sexually reproducing populations of both N. leucoloma and N. peregrinus occur in their native ranges (Argentinian Mesopotamian region), where they overlap. In 2013, after several decades during which only females had been recorded, a few males potentially belonging to these species were discovered. To clarify their taxonomic identity and understand the group’s evolutionary dynamics, we analyzed their mitochondrial and nuclear genetic markers to assess their genetic variation distribution and infer their phylogenetic relationships. Molecular phylogenetic analyses revealed that these males constitute an independently evolving lineage, whereas morphological comparisons produced inconclusive results. Statistical tests confirmed introgression between these unidentified males and N. leucoloma. These findings uncover unexpected levels of genetic divergence within this group of Neotropical weevils.