Haplotype analysis of global chili thrips (Scirtothrips dorsalis) populations using the metazoan barcode

Scirtothirps dorsalis is a globally invasive polyphagous crop pest infesting several major field and ornamental crops. Established in Florida since 2005, it had spread to Texas within one year. Establishing a putative source locality of the US population would help stakeholders target effective control and quarantine strategies for this pest. But this effort is complicated by phylogenetic and morphological evidence suggesting that S. dorsalis may be a cryptic species complex. In an attempt to overcome these challenges, the metazoan barcode region of the mitochondrial CO1 gene of chili thrips populations from Israel, China, Singapore, India, and the US was sequenced, aligned, and analyzed using statistical parsimony. We report the patterns of diversity found within this species including particularly high haplotype diversity in Indian populations. We discuss the implications of our results for the phylogenetics of S. dorsalis and the origin of the US population.