Fig. 2.

Exposure to dead conspecifics alters physiology and lifespan in Drosophila melanogaster. a When D. melanogaster were exposed to dead animals from each of two closely related species (D. simulans and D. erecta), they presented aversive cues, but exposure to the evolutionarily more distant D. virilis had no effect (N = 10 for D. erecta, N = 8 for D. simulans, and N = 17 for D. virilis, P = 0.046 for D. erecta and P = 0.008 for D. simulans, group analysis of variance (ANOVA) P < 0.001). Inset depicts a phylogeny of related Drosophila species. b–d Flies exposed to dead conspecifics exhibited reduced b starvation survival (N = 100 per treatment, P < 0.001), c triacylglyceride stores (TAG, N = 8 biological replicates of 10 flies each), and d metabolic rate as measured by CO₂ production relative to unexposed animals (N = 21 biological replicates of 5 flies/treatment). e, f While exposure to dead conspecifics did not affect e spontaneous movement rates (N = 6 for each treatment, P = 0.26), f forced climbing was impaired relative to unexposed animals (N = 18 for each treatment). g Chronic exposure to dead animals significantly reduced lifespan flies (N = 190 for unexposed, 212 for exposed, P < 0.001). For a, naive choosing flies were from the Canton-S strain. Each T-maze sample tests 20 flies. Error bars represent standard error of the mean (SEM). P values for binary choice were determined by non-parametric randomization. Comparison of survival curves was via log-rank test, and the remaining phenotypes were evaluated for significance by t test (see Methods for details)