Genetic differentiation of host-associated populations of cotton fleahopper (Pseudatomoscelis seriatus) in Texas

Specialized associations with different host plant species can reduce gene flow between host-adapted insect populations and genetically differentiate host-associated populations. Host plants may function as differentially selective environments that could cause insect populations to have distinct genotypes. This phenomenon is a special case of ecological speciation commonly referred to as host associated differentiation (HAD). Most of the reported cases of HAD involve insects that either have an intimate relationship with their hosts such as endophagous insects feeding inside galls, fruits, or seeds and/or insects with reduced genetic recombination such as parthenogenetic species.  However, HAD is not restricted to endophagous or parthenogenetic insects. Here, we investigate HAD in a polyphagous and non-parthenogenetic insect, the cotton fleahopper (CFH), Pseudatomoscelis seriatus. A previous study showed HAD in CFH feeding on horsemint, Monarda punctata. Importantly, CFH is associated with about 160 plant species from 35 families, so it is unlikely that HAD is present only on a single plant species. Here, we investigate the prevalence of HAD in CFH associated with 13 host plant species from 7 families collected from 14 locations. We screened ~20 individuals of CFH per host plant species using amplified fragment length polymorphisms (ALFPs) previously developed for CFH. Population assignment tests indicate that HAD is not common in CFH. Implications of HAD, or the lack thereof, in the management of this polyphagous pest are discussed.