These results suggest that the immune sexual dimorphism common in Drosophila lines is dependent on the specific interactions of each pathogen with immune pathways that contain some components (e.g., PGRP-SA) differentially affecting survival of males and other components (e.g., Relish) differentially affecting survival of females, at least in some lines and to some infections. The gene discussed is PGLYRP1; the disease is infection.