Fig. 1.

Effects of infection on Drosophila attraction and odor profile. a Experimental design of attraction assays. b Attraction index of adult Drosophila toward the olfactory cues from Pseudomonas bacteria or from growth media control. c Attraction indices or naive wild type or Orco mutant flies given the choice between other adults with and without Pseudomonas infection or between frass of flies with or without infection. Attraction index: ((no. of flies in treatment trap) − (no. of flies in control trap)) / total no. of flies. d, e GC-MS profile of female d and male e Drosophila adults either infected with Pseudomonas entomophila bacteria or mock-infected with growth media (healthy control). Numbers from GC-MS refer to FID peaks: (1) bromodecane (internal standard); (2) methyl laurate; (3) lauric acid; (3) methyl myristate; (5) myristic acid; (6) methyl palmitoleate; (7) methyl palmitate; (8) palmitoleic acid; (9) palmitic acid; (10) methyl linoleate; (11) methyl oleate; (12) methyl stearate; (13) oleic acid; (14) Z-11-cis-vaccenyl actetate (cVA); (15) 7-Z-tricosene; (16) heneicosane. f Amount of methyl laurate produced over time, from 4 to 48 h after infection with several strains of bacteria (for time courses of other compounds see Supplementary Fig. 2D). g Example of SSR responses of healthy Drosophila antennal trichoid (at4) neurons to body washes of infected or healthy Drosophila. Stimulus: 0.5 s. h Quantified SSR responses toward healthy or infected fly body washes, including recordings from wild-type at4 and at1 neurons, as well as from fly mutants for Or47b and Or88a pheromone OSNs. i Attraction indices of adult Drosophila toward healthy frass perfumed with treatment odors or solvent control. Frass was perfumed either with all odors (All) that were increased after infection or with a subset. 4FAs: mixture of fatty acids increased after infection that were reported to act as pheromones (lauric acid, myristic acid, palmitoleic acid, and palmitic acid, Lin et al.³⁶ ); 3 MEs: methyl esters (ML, MM, and MP) increased after infection and reported to act as pheromones (Dweck et al.³⁵). More details in Supplementary Fig. 2A. j Schematic of septic or systemic infection location for both bacterial and mock infection. Filled boxes denote significance from zero