Uropygial gland size and composition varies according to experimentally modified microbiome in Great tits

Table 4 Analyses of preen gland volume and PC2 composition of secretions for each sex

a	Uropygial gland volume
	Females			Estimate ± SE	df	F	P
		Date		0.01 ± 0.01	1,50	4.25	0.04
		Year		0.15 ± 0.04	1,50	13.89	<0.001
		Wing length		0.41 ± 0.13	1,50	10.6	0.002
	Males			Estimate ± SE	df	F	P
		Date		−0.01 ± 0.004	1,36	7,0	0.01
		Year		0.21 ± 0.06	1,36	13,0	0.001
		Body condition		0.16 ± 0.04	1,36	12.5	0.001
		Treatment	Nisin	0.16 ± 0.07	2,36	4.3	0.02
			TSB	0.16 ± 0.06
b	Uropygial gland composition - PC2
	Females			Estimate ± SE	df	F	P
		Date		0.07 ± 0.03	1,27	5.5	0.03
		Treatment	Nisin	2.38 ± 0.69	2,27	6.5	0.005
			TSB	1.95 ± 0.71
	Males			Estimate ± SE	df	F	P
		Body condition		−0.51 ± 0.22	1,21	5.4	0.03

The compounds produced and their contribution to the principal components are given in Table 1. The table present final models after backward selection. Treatment effects estimates compared to the control are shown.

ISSN: 2730-7182