Bacterial microcosms obey Taylor's law: effects of abiotic and biotic stress and genetics on mean and variance of population density

Ecological Processes

Table 1 Estimates of intercept and slope (± standard error) from linear regressions of log-variance on log-mean

	Intercept	Slope	95% C.I. [lower; upper]	Adjusted R ²	n
Overall	0.38 ± 0.29	1.89 ± 0.03	[1.83; 1.96]	0.99	40
Plate
KB	5.62 ± 1.23	1.33 ± 0.13	[1.06; 1.61]	0.85	20
KB+rif	0.28 ± 0.36	1.91 ± 0.04	[1.81; 2.00]	0.99	20
Strain
MutS/Rif-	-0.36 ± 0.83	1.97 ± 0.10	[1.75; 2.19]	0.98	10
MutS/Rif+	3.47 ± 1.78	1.57 ± 0.19	[1.14; 2.00]	0.89	10
WT/Rif-	0.44 ± 0.25	1.87 ± 0.03	[1.80; 1.94]	0.99	10
WT/Rif+	2.94 ± 0.98	1.62 ± 0.11	[1.37; 1.87]	0.96	10
Rif- (pooled)	0.22 ± 0.34	1.90 ± 0.04	[1.82; 1.99]	0.99	20
Rif + (pooled)	2.98 ± 0.75	1.62 ± 0.08	[1.45; 1.79]	0.96	20
WT (pooled)	0.62 ± 0.31	1.87 ± 0.04	[1.79; 1.94]	0.99	20
MutS (pooled)	-0.25 ± 0.61	1.96 ± 0.07	[1.82; 2.11]	0.98	20
Treatment
Ancestor	-0.30 ± 0.31	1.92 ± 0.04	[1.84; 2.01]	0.99	8
Control	-0.21 ± 0.52	1.95 ± 0.06	[1.81; 2.10]	0.99	8
Rifampicin	-33.71 ± 7.12	5.43 ± 0.74	[3.68; 7.18]	0.90	8
Phage	0.97 ± 0.56	1.86 ± 0.07	[1.69; 2.03]	0.99	8
Rifampicin and phage	3.95 ± 0.81	1.51 ± 0.09	[1.29; 1.73]	0.97	8

Least-squares regressions of log₁₀ variance of bacterial density on log₁₀ mean density (in colony-forming units per milliliter) were fitted across all data (overall) or fitted separately for the different assay environments (plate), bacterial strains, and long-term treatments. For each regression, the 95% confidence interval (C.I.) for the slope is given. Bold type indicates slopes significantly different from +2 (upper and lower boundaries calculated as mean slope ± t_{n-1, 95%}× standard error). False discovery rate method was used to correct for multiple testing (García 2004). Also given are the adjusted R² and the number of data points (n).