Figure 6.

Effect of axenic growth on measures of host physiology

Mated male flies were raised in parallel to the indicated ages under either conventional or axenic conditions. They were then subjected to the indicated stressor and percent survival was assayed at the times of treatment shown. In all graphs, black line is a survivorship curve post-treatment for conventionally raised flies and red is for axenic. Plotted values are mean ± SEM; pvalues are indicated (Mantel-cox logrank test) and number of flies used is indicated in parentheses. ns denotes “not significant (p > 0.05).

(A–C)(A) Hydrogen peroxide (H₂O₂, 5%), Survival curve shows data pooled from 5-6 biological replicates (B) Starvation conditions. Survival curve was generated using five biological replicates (C) Pathogen challenge. Flies were pricked in the thorax with a needle dipped in an active culture of the Erwinia carotovora subsp. carotovora or with a sterile control. Fifty flies were infected for each age and condition, however, only those that survived the pricking were scored further. Control survivorship curves: dotted purple line for sterile pricking of conventionally raised flies; dotted cyan line for sterile pricking of axenic flies. Raw survival data per vial is provided in Table S13.

(D)χ² periodogram of rhythmic flies. Wild type conventionally-raised or axenic flies of the indicated ages entrained to 12:12 light:dark cycle were put in constant dark, and activity was monitored for 8 days. Within each panel, each line shows the correlation of activity with circadian period (Qp) for one fly over a range of potential periods (18–30 hr; χ²). The peak of the curve is taken to indicate the circadian period for that individual. n = 32 flies for each condition were set up.

(E) Fraction of flies of the indicated age and microbial status showing statistically significant rhythmic behavior, based on the periodogram. Percentage of rhythmic flies was calculated based only on those that survived the entire experiment. Significance calculated by Fisher’s Exact Test.

See also Figures S8–S10.