Fig. 1

Schematic drawing of the entomopathogenic nematode cycle, with the Photorhabdus and Xenorhabdus bacteria, demonstrating their symbiosis. The nematodes roam freely in the soil until they find a host insect, in the scheme represented by a caterpillar. The nematodes, when entering the host and settling in the hemocoel, release the bacteria through defecation or regurgitation. The bacteria proliferate in the hemocoel and become infectious, when they release toxic molecules to the host, leading to their death. Nematodes use the host’s carcass to reproduce and return to the habitat carrying the bacteria, restarting the cycle until the nematodes find a new host insect