Table 1.

Results from five independent experiments studying the effects of selection on longevity

Source	Proportional hazard analysis
	df	χ2	P
Linea	4	151.24	<0.001
Selectiona	1	35.47	<0.001
Lineb	4	62.11	<0.001
Selectionb	1	108.93	<0.001
Line	4	127.18	<0.001
Selection	1	167.52	<0.001
Line	4	27.5232	<0.001
Selection	1	192.708	<0.001
Line	4	205.33	<0.001
Selection	1	32.82	<0.001

The proportional hazard analysis of mortality risk was performed with line nested within the selection regime

^aMated longevity without antibiotics in the medium

^bCorrelated response of virgin longevity with antibiotics in the medium. The remaining experiments investigated mated longevity with antibiotics in the medium