Table 2. Summary of the details of the experiments.

Experiment	Number of pairs	Number of voles Males Females		Criteria for pairing	Response variable in the statistical analysis
Vole population size	5	25	25	Same sex, approximately the same initial body mass.	Difference in the number of voles between E+ and E− in a enclosure pair after four and a half months.
Vole body mass	36	42	30	Same sex, approximately the same initial body mass.	Difference in body mass (g) between E+ and E− in a vole pair after feeding the voles seven days.
Prey preference of weasel	24	36	12	Same sex and length of the feeding period, approximately the same initial body mass.	Difference in the number of belt crossings per hour between E+ and E− in a vole pair
Prey preference of weasel	17*)	24	10	Same sex and length of the feeding period, approximately the same initial body mass.	E+ vole captured in a pair of voles fed on E+ and E− (yes, no)
Odour preference of weasel	21*)	42	0	Same sex and length of the feeding period, approximately the same initial body mass.	Bedding of E+ vole chosen in a E+ and E− bedding pair (yes, no)

*)Also the number of least weasels.