Comparative genetic diversity and structure of Rhus gall aphid Schlechtendalia chinensis and its host plant Rhus chinensis.

Investigating the population genetic structure of parasites and their host plants can provide valuable insights into their coevolutionary processes. In this study, we assessed and compared the population genetic diversity and structure of 12 Rhus gall aphid (Schlechtendalia chinensis) populations and their respective host plant (Rhus chinensis) using amplified fragment length polymorphism (AFLP) markers. Analysis of molecular variance (AMOVA) revealed that both the aphid and its host plant exhibited higher genetic variance within populations than among them, indicating that their coevolutionary history may have produced analogous patterns of population genetic structure. Additionally, we considered alternative factors that could contribute to this outcome, such as intraspecific gene flow, hybridization, or environmental influences. Our analysis did not reveal a significant correlation between genetic and geographic distances of either the aphid or host plant populations, leading us to reject the isolation-by-distance model as a plausible explanation for the demographic histories of these two species.