Table 1. Results of the statistical tests.

stimulus 1	N	stimulus 2	N	focal female	behavior	Mann-Whitney U	U	Z
Intraspecific test (I. alpestris+I. alpestris)
Ia	20	MW	20	I. alpestris	f	<0.001*	42.000	−4.621
					tt	<0.05*	123.000	−2.207
					w	<0.01*	126.500	−2.719
Ia	20	W	20	I. alpestris	f	<0.001*	30.000	−5.109
					tt	<0.001*	93.000	−3.269
					w	<0.05*	120.000	−3.097
MW	20	W	20	I. alpestris	f	0.152	180.000	−1.432
					tt	0.130	156.000	−1.514
					w	0.317	190.000	−1.000
Interspecific test (I. alpestris+L. helveticus)
Ia	15	W	15	I. alpestris	f	<0.001*	90.000	−3.782
					tt	<0.001*	22.500	−4.215
					w	<0.05*	75.000	−2.396
Lh	15	W	15	I. alpestris	f	1.000	112.500	0.000
					tt	0.150	97.500	−1.438
					w	1.000	112.500	0.000
Interspecific test (I. alpestris+L. helveticus)
Ia	15	W	15	L. helveticus	f	1.000	112.500	0.000
					tt	0.524	104.500	−0.637
					w	1.000	112.500	0.000
Lh	15	W	15	L. helveticus	f	<0.001*	37.500	−3.707
					tt	<0.05*	69.000	−2.225
					w	0.317	105.000	−1.000
Intraspecific vs. interspecific female preference
Ia (+I. alpestris)	20	Ia (+L. helveticus)	15	I. alpestris	f	0.340	121.500	−0.954
					tt	0.183	110.500	−1.333
					w	0.398	128.000	−0.846

Ia = alpine newt male courtship water, MW = water in which non-courting alpine newt males had been kept, W = control water, Lh = palmate newt male courtship water, N = number of different females used in the experimental design. P-values smaller than 0.05 are considered significant and are indicated with an asterisk. The values for Kruskal-Wallis tests were as follows: intraspecific tests (P_f<0.05, P_tt<0.05 and P_w<0.05), interspecific tests for alpine newt females (P_f<0.05, P_tt<0.05 and P_w<0.05), interspecific tests for palmate newt females (P_f<0.05, P_tt<0.05 and P_w = 0.096).