Table 1.

Relationships between morphometric sperm traits within passerine families. Sample size (n), least-squares slope (LS slope) and standard error of slope (s.e.), R² and t-value for PGLM regression are presented. RMA regression slopes were compared with slope = 1 (t for slope = 1) and among families (t for each family pair). Asterisks next to t-values indicate significance levels. *p < 0.05, **p < 0.005.

	n	LS slope	RMA slope	s.e.	R2t	t	slope = 1 (t)	Sylviidae (t)	Fringillidae (t)	Emberizidae (t)	Estrildidae (t)	Parulidae (t)
Head–midpiece
Sylviidae	25	0.09	0.32	0.06	0.08	1.42	11.33**
Fringillidae	16	0.25	0.26	0.02	0.90	10.99**	37.00**	0.95
Emberizidae	17	0.40	0.47	0.07	0.72	6.19**	7.57**	1.63	2.91*
Estrildidae	22	0.15	0.23	0.04	0.43	3.90**	19.25**	1.25	0.67	2.96*
Parulidae	30	0.41	0.55	0.07	0.55	5.86**	6.43**	2.50*	4.03**	0.81	3.95
Icteridae	32	0.14	0.28	0.04	0.25	3.16**	18.00**	0.56	0.27	2.35*	0.88	3.33**
head–flagellum
Sylviidae	25	0.24	0.76	0.15	0.10	1.58	1.60
Fringillidae	16	0.66	0.81	0.12	0.67	5.39**	1.58	0.26
Emberizidae	17	0.44	0.53	0.08	0.69	5.8**	5.88**	1.35	2.00
Estrildidae	22	0.32	0.75	0.15	0.18	2.12*	1.67	0.05	0.32	1.29
Parulidae	30	0.42	0.79	0.07	0.28	5.67**	3.00**	0.19	0.14	2.36*	0.24
Icteridae	32	0.21	0.40	0.07	0.28	3.15**	8.57**	2.25*	2.93**	1.18	2.06*	3.98**
midpiece–flagellum
Sylviidae	25	2.29	2.58	0.25	0.79	9.31**	6.32**
Fringillidae	16	1.20	1.27	0.11	0.89	10.49**	2.46**	4.85**
Emberizidae	17	1.11	1.12	0.02	0.99	64.33**	6.00**	5.84**	1.36
Estrildidae	22	3.07	3.29	0.27	0.87	11.45**	8.48**	1.92	6.97**	8.04**
Parulidae	30	1.06	1.06	0.01	0.99	104.99**	6.00**	4.11**	1.91	2.73*	8.26**
Icteridae	32	1.40	1.46	0.08	0.92	18.44**	5.75**	4.31**	1.36	4.15**	6.54**	4.94**