Genetic structure and haplotype diversity in Indian populations of brown plant hopper, Nilaparvata lugens stal using mtCOI

The brown planthopper, Nilaparvata lugens Stal is a key pest of rice in Asia, causing extensive crop losses and transmitting major viruses. We analysed mitochondrial cytochrome oxidase I (mtCOI) sequences from 63 field-collected samples representing 21 populations across ten states to understand its genetic structure across India's diverse agroclimatic zones. Our analysis revealed two highly conserved haplotypes, with one major haplotype shared across over 85% of individuals. This consistent haplotype distribution is supported by a TCS network and minimal mutational steps and this reflects strong genetic cohesion across geographically distant populations. Population genetic parameters, neutrality tests, and mismatch distribution patterns support a recent demographic expansion of N. lugens in India. A majority of genetic variation was observed within populations, with only subtle regional differences, as confirmed by AMOVA and phylogenetic tree topology. These results indicate robust gene flow and suggest that Indian populations are highly interconnected, likely facilitated by seasonal migration and shared agricultural practices. Our study offers one of the most comprehensive mitochondrial diversity assessment of Indian N. lugens to date and provides critical genetic benchmarks for future monitoring, resistance management, and predictive modelling of BPH outbreaks in the subcontinent.