Thrips composition in cotton agroecosystem: a single species or a species complex?

Abstract

Abstract Thrips have emerged as a major sucking pest of cotton, limiting crop productivity through direct feeding and virus transmission. Cotton thrips have been long presumed to be a single species, with all the studies from northern India reporting it as Thrips tabaci. Even the majority of work from southern and central India reports it as the sole species, T. tabaci in their studies conducted on pesticide efficacy, population dynamics, host plant resistance, and others. The present study has attempted to decode the thrips species composition in cotton collected from 22 locations representing the north-western, central, and southern zones of India using both morphological and molecular tools. The studies report the prevalence of a thrips species complex in cotton, which is dominated by Thrips palmi with the coexistence of other thrips species, viz., T. tabaci, Scirtothrips sp., and Frankliniella schultzei. Our studies also suggest the maiden report of Chaetanaphothrips orchidii and Asprothrips bimaculatus thrips species in cotton from India. The T. palmi genetic diversity analysis revealed the presence of cryptic species, and haplotyping showed the existence of 53 haplotypes globally, out of which two new haplotypes have been reported in the present study. The possible reasons for the change in cotton thrips composition from a single species to a complex over the years have also been analyzed using historical population dynamics data from the past 15 years, which indicates that the invasion of new species over the previous years might be responsible for the change in the population structure of thrips in cotton.