Phenotypic differentiation of two host-associated populations of cotton fleahopper

Taxonomically unrelated host plant species present variable feeding environments for phytophagous insects. Phytophagous insects could respond to these differences by presenting populations differentially adapted to the host-plant species they most often encounter or by presenting phenotypic plasticity. The cotton fleahopper, Pseudatomoscelis seriatus, is a phytophagous insect native to North America that feeds on more than 120 host plant species. Barman et al. have found the existence of genetically distinct host-associated populations in this insect. However, host-associated differentiation (HAD) in this species is not ubiquitous but location specific. Strong differential selection for specific adaptive traits on different host-plant species may explain HAD in the cotton fleahopper. In this study, we are testing if populations of the cotton fleahopper in horsemint and cotton present differences in morphometric parameters. We measured an ensemble of morphological characters (antenna, mouthparts, wings, legs) obtained from adult cotton fleahoppers on horsemint and cotton to test for phenotypic differentiation. Fleahoppers collected from horsemint and cotton was reared in controlled conditions on their respective host-plant species, and their offspring was used for morphometric measurements. In this study, we present the results of morphometric comparisons. Our results will offer insights into phenotypic characteristics that could promote reproductive isolation leading to HAD and the creation of host races in this pest species.