Systematics, diversity and biogeography of entomopathogenic nematodes and their bacterial symbionts

Since the discovery of the first entomopathogenic nematode in 1923, our understanding of their systematics and biogeography has advanced significantly. This review outlines the historical development of research on systematics of entomopathogenic nematodes and their bacterial symbionts, while presenting the current state of knowledge in these fields. Additionally, we evaluate the status of several recently described but dubious EPN species and provide an updated list of valid Heterorhabditis and Steinernema species. Finally, we summarize existing data on the geographical distribution of entomopathogenic nematode species and draw general conclusions about their biogeography.