larvae are tolerant to oral infection with the bacterial pathogen .

The fruit fly is an excellent model for dissecting the molecular and functional bases of bacterial pathogenicity and host antibacterial immune response. The Gram-negative bacterium is an insect-specific pathogen that forms a mutualistic relationship with the entomopathogenic nematode . Here we find that oral infection of larvae with moderately reduces their survival ability while the bacteria replicate efficiently in the infected insects. This information will contribute towards understanding host gut immunity against potent bacterial pathogens.