Table 2. Summarized information of experiments 1 to 4 (limited choice).

For each experiment are displayed the sex and the species of the choosing partner (such as female choice or male competition), the number of observed homo- and hetero-specific pairs and the number of worms that remained single. Sh = S. haematobium and Sb = S. bovis. Expected number of pairs under random mating hypothesis is shown in brackets (see the statistics section in Materials and Methods for details). Chi-square statistic, degree of freedom and P-value are given for each hamster, for each experiment and for all experiments combined. * indicates significant results at 5% level. In Exp. 3, worms from only two hamsters could be analysed, while others died prematurely (two hamsters) or presented too few numbers of paired worm (one hamster).

Exp.	Host	Choosing partner	Homo-specific pairs	Hetero-specific pairs	Single worms		χ2-statistic	d.f.	P-value
Exp. 1			♂ Sh x♀ Sh	♂ Sh x♀ Sb	♀ Sh	♀ Sb	11.104	4	0.049*
1	1	♂ Sh	11 (14)	14 (11)	20	9	1.838	1	0.175
1	2	♂ Sh	11 (15)	22 (18)	15	11	1.543	1	0.214
1	3	♂ Sh	14 (20)	16 (10)	25	4	5.057	1	0.025*
1	4	♂ Sh	9 (9)	6 (6)	36	26	0.015	1	0.903
1	5	♂ Sh	10 (13)	10 (7)	41	15	2.651	1	0.103
Exp. 2			♀ Sh x ♂ Sh	♀ Sh x ♂ Sb	♂ Sh	♂ Sb	3.118	4	0.682
2	1	♀ Sh	10 (9)	2 (4)	7	5	0.908	1	0.341
2	2	♀ Sh	6 (5)	1 (2)	0	1	0.429	1	0.513
2	3	♀ Sh	12 (10)	3 (5)	11	10	1.688	1	0.194
2	4	♀ Sh	16 (15)	3 (4)	6	2	0.094	1	0.759
2	5	♀ Sh	12 (12)	13 (13)	11	12	0.001	1	0.993
Exp. 3			♂ Sb x♀ Sb	♂ Sb x♀ Sh	♀ Sb	♀ Sh	4.522	1	0.104
3	2	♂ Sb	4 (2)	0 (2)	46	55	4.400	1	0.036
3	3	♂ Sb	2 (1)	1 (2)	22	32	0.742	1	0.389
Exp. 4			♀ Sb x ♂ Sb	♀ Sb x ♂ Sh	♂ Sb	♂ Sh	3.246	4	0.662
4	1	♀ Sb	15 (12)	17 (20)	4	14	1.070	1	0.301
4	2	♀ Sb	10 (8)	25 (28)	2	19	1.061	1	0.303
4	3	♀ Sb	3 (3)	8 (8)	4	13	0.030	1	0.862
4	4	♀ Sb	9 (8)	15 (16)	8	19	0.188	1	0.665
4	5	♀ Sb	49 (49)	15 (15)	18	5	0.007	1	0.932
All Exp.							21.719	16	0.152