Landscape genomics and demographic history of

Megamelus scutellaris Berg (Hemiptera: Delphacidae) is a South American herbivore insect exclusively associated with water hyacinth (Pontederia crassipes Mart.) as a feeding and breeding resource. Megamelus scutellaris has been introduced as a biological control agent in water bodies in the United States and South Africa in order to control this aquatic weed. This planthopper is native to the wetlands across South America, ranging from the Amazon river basin to the Río de la Plata river basin. In this study, we combined nuclear genome-wide SNP data with mitochondrial DNA (mtDNA) to evaluate the genetic variation of the planthopper in its native range. First, we examined the population structure and phylogeographic patterns of M. scutellaris across an area comprising the main river basins of its distribution in Argentina and Southern Paraguay. To evaluate the divergence and connectivity of the identified genetic groups, we used a coalescent based simulation approach, enabling a more precise understanding of the demographic history of these populations. Furthermore, we incorporated a landscape genomics framework combined with ecological niche modeling to investigate potential environmental factors driving the observed patterns of genetic differentiation in M. scutellaris.