highly significantp < .001
The rest of a small but highly significant amount of genetic variance corresponded to differences between countries (27.93%, p < .001) and among sampling sites within countries (11.99%, p < .001; Table 4 ). 4 DISCUSSION 4.1 Suitable analysis method for P. americana identification It is difficult to identify cockroaches by morphology due to several factors including phenotypic plasticity, developmental stochasticity, and sexual dimorphism.