Population genetic structure of cotton fleahopper, Pseudatomoscelis seriatus (Hemiptera: Miridae)

The cotton fleahopper, Pseudatomoscelis seriatus (Hemiptera: Miridae) is an economic pest of cotton predominately in Texas, Arkansas and Oklahoma. However, distribution range of cotton fleahopper occupies southwestern United States and northern Mexico. Cotton fleahopper is polyphagous with over 160 documented host-plant species. Although, cotton is not the most preferred host, the cotton fleahopper distribution range in the United States appears to coincide with states producing cotton. We studied genetic structure of cotton fleahopper populations associated with cotton in 11 cotton producing states and on three host-plant species in Texas. For genetic characterization, we used amplified fragment length polymorphism markers (AFLP) and mitochondrial cytochrome oxidase I (COI) sequence data. A Bayesian analysis of 220 AFLP loci from 272 individuals collected in 11 states revealed no population structure. In contrast, an analysis of 432 AFLP loci obtained from 192 individuals representing 13 populations associated with 3 host-plants (cotton, horsemint, and woolly croton) in 5 Texas locations revealed distinct population structure. The horsemint-associated cotton fleahopper populations in three locations (Lubbock, San Angelo, and College Station) were genetically distinct from cotton and/or woolly croton associated populations. While AFLP data revealed significant genetic differentiation, COI sequence data failed to detect genetic differentiation among different host-plant associated populations, which indicates a relatively recent differentiation of horsemint associated populations. Our results show that cotton fleahoppers are not genetically structured when associated with cotton within wide geographic distribution but are genetically structured by host-plant association in Texas.