Population Genetics and Phylogeography of Thrips tabaci (Thysanoptera: Thripidae) Across Different Host Plants

Abstract

Thrips tabaci (Thysanoptera: Thripidae), commonly known as onion thrips, is a highly polyphagous insect pest that infests numerous agricultural and horticultural crops worldwide. In addition to causing direct feeding damage, T. tabaci is an important vector of several plant viruses, leading to substantial economic losses in diverse cropping systems. Its broad host range and strong adaptability to different environmental conditions contribute to considerable genetic variability and population differentiation. The present study was conducted to investigate the population genetics and phylogeographic structure of T. tabaci populations collected from different host plants across multiple geographic regions. Thrips specimens were collected from a range of cultivated host species, and genomic DNA was extracted for molecular analysis. Genetic diversity and population structure were assessed using mitochondrial and nuclear molecular markers, followed by phylogenetic and phylogeographic analyses to determine evolutionary relationships, gene flow, and host-associated differentiation among populations. The results revealed substantial genetic variation among T. tabaci populations associated with different host plants and geographic regions. Phylogenetic analysis identified distinct genetic lineages, suggesting the existence of host-associated population structuring and possible cryptic diversity within the species complex. Certain populations exhibited strong genetic similarity despite geographic separation, indicating potential long-distance dispersal and movement through agricultural trade and crop cultivation practices. Population genetic analysis also demonstrated varying levels of gene flow and differentiation among host-associated populations, reflecting adaptation to specific host plants and environmental conditions. The findings provide important insights into the evolutionary biology, dispersal patterns, and host-associated genetic structure of T. tabaci. Understanding the population genetics and phylogeography of this pest is essential for improving pest monitoring, predicting spread dynamics, and developing effective integrated pest and resistance management strategies across different cropping systems.