Supporting information
Sample sizes are given in table S1 and the design in table S2. Evidence that relationships are
fairly linear is given in fig. S1 and S2. Parameter estimates for the model with “treatment” as
random term is given in fig. S3.
Table S1. Sample size (n) per female age class for reindeer in Finland. Age is given at the
time of mating (late September-October), so one year must be added to get age at calving
(May-early June).
Age
n
1
7
2
9
3
16
4
10
5
6
6
12
7
11
8
9
9
3
10
4
12
1
Total
88
Table S2. Reindeer breeding herd structure during the rut for the manipulated treatments of males present. Column gestation gives the sample
size used in this study. Mass (kg) gives the live body mass in mid–September, just prior to the rut and age is given in years. Lau = Lauluvaara;
Sin = Sinioivi. Treatment 5 was excluded due to lack of observations; treatments 11 and 13 since this involved vasectomised males (cfr. Holand
et al. 2006).
Treatment
1
2
3
4
6
7
8
9
10
12
14
Sum
Location
Lau
Sin
Lau
Sin
Sin
Sin
Sin
Sin
Sin
Sin
Sin
Year
1996
1996
1997
1997
1999
2000
2001
2002
2003
2004
2005
Gestation
(n)
4
3
8
8
4
18
10
8
13
11
1
88
Females
No
females
Av. Age
46
43
47
47
75
75
80
92
53
49
46
5.1
5.1
4.5
4.5
4.6
4.5
5.2
5.1
5.5
5.0
5.8
Males
Av.
Mass
76.9
79.5
75.8
73.6
74.5
76.8
83.6
84.0
80.7
84.4
78.5
No
males
6
6
4
18
3
3
11
4
4
4
17
1 yr
6
3
4
9
0
3
11
2
1
2
10
2 yr
3 yr
0
0
0
6
0
0
0
1
1
0
4
4 yr
0
0
0
0
0
0
0
0
2
0
1
5 yr
0
3
0
0
3
0
0
1
0
2
0
Mass
range
0
0
0
3
0
0
0
0
0
0
2
74-99
75-140
75-76
59-139
120-140
61-68
68-89
75-105
95-120
95-148
67-145
Av.
Mass
79.5
103.8
75.3
84.6
131
64.3
79.2
100.3
108.5
119
93.8
te( ma
e
tedat
, fema
leage
Fe
ma
le
age
, 3)
Da
te
of
ma
tin
g
Fig. S1. Gestation length (days) as a function of female age (yrs) and date of mating (Julian
date) for reindeer in Kaamanen, Finland using AM plot within the R environment. Note that
there was no significant interaction between the two continuous covariates.
15
10
5
-10
-5
0
Date of mating
10
0
-10
-20
Female body mass
2
4
6
8
10
12
2
4
10
12
5
0
-10
-5
Gestation length
0
-5
-10
Gestation length
8
Female age
5
Female age
6
2
4
6
8
Female age
10
12
275
280
285
290
295
300
Date of mating
Fig. S2. AM plots within the R environment showing absence of marked non-linear effects.
Fig. S3. Path analysis of the direct and indirect relationship of factors affecting gestation
length in female reindeer, Finland. This is the same model as for Fig. 2A, with the exception
of the random term being here “treatment” instead of “female ID”.