Neoleucinodes elegantalis (Guenée) population structure and isolation by distance in central and South America revealed with cytochrome oxidase i (CO1) gene

Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is an oligophagous pest in the Western Hemisphere and found on cultivated and wild Solanaceae species. In Colombia, the insect has diverged into four host races according to variation in female genitalia size, wing morphometrics, and haplotype. Adult insects were collected on Solanaceae species from Argentina, Brazil, Colombia, Ecuador, Honduras, and Venezuela. Sequencing of 586 bp of the mitochondrial gene Cytochrome Oxidase 1 (CO1) in 276 individuals produced 50 haplotypes. AMOVA confirmed population structuring (F_ST = 0.73, P < 0.0001). UPGMA dendrogram for F_ST paired distances indicated the Andes Mountains influenced the genetic differentiation of the pest as previously reported in Colombia. The pest might have passed through political and geographical borders by free commercialization of Solanaceae fruit from Ecuador (S. quitoense) and Honduras (S. melongena) because much genetic similarity was found between races from both countries. The Tajima test (D) indicated that populations of N. elegantalis from Brazil and Ecuador had expanded recently whereas populations from other countries were in equilibrium. Mismatch analysis showed populations of the pest expanded in Central and South America from 338,000 to 1.3 million years ago, suggesting haplotype race divergence occurred before domestication of Solanaceae plants in the Americas (10,000 years ago). The Mantel test was significant (r² = 0.1943, p < 0.0001), suggesting isolation by distance, particularly in South America.