AbstractChaetosiphella stipae stipaeis a xerothermophilous aphid, associated with Palaearctic temperate steppe zones or dry mountain valleys, where there are grasses from the genusStipa. Its geographical distribution shows several populations that are spread from Spain, across Europe and Asia Minor, to Mongolia and China. Geographical variation in chaetotaxy and other morphological features were the basis to consider whether individuals from different populations are still the same species. Moreover, usingCh. stipae stipaeandStipaspecies occurrences, as well as climatic variables, we predict potential geographical distributions of the aphid and its steppe habitat. Additionally, forStipaspecies we projected current climatic conditions under four climate change scenarios for 2050 and 2070. While highly variable, our results of morphometric analysis demonstrates that allCh. stipae stipaepopulations are one very variable subspecies. And in view of predicted climate change, we expect reduction ofStipagrasslands. The disappearance of these ecosystems could result in stronger separation of the East-European and Asian steppes as well as European ‘warm-stage’ refuges. Therefore, the geographic morphological variability that we see today in the aphid subspeciesCh. stipae stipaemay in the future lead to speciation and creation of separate subspecies or species.