Results
Leaf-out and first flowering day were significantly positively
correlated in all years, and correlation coefficients ranged from 0.32
to 0.46 (Pearson’s correlation; 2013: r = 0.46, t196 =
7.29, p < 0.001; 2014: r = 0.41, t201 = 6.44,
p < 0.001; 2015: r = 0.32, t205 = 4.77, p
< 0.001; Fig. 1).
There was total selection for earlier leaf-out in all years (Table 1a).
Selection on leaf-out day in 2015 was nonlinear, fitness being highest
in individuals with an early to intermediate leaf-out day (Table 1a;
Fig. 2a). There was total selection for earlier flowering in 2013 and
2014, but not in 2015 (Table 1b; Fig. 2b). We found no evidence of
nonlinear selection on first flowering day in any of the study years
(Table 1b).
There was direct selection for earlier leaf-out in 2013, but in 2015
selection favoured later leaf-out instead (Table 1c; Fig. 2a). There was
no direct selection on leaf-out in 2014. Direct phenotypic selection
favoured earlier flowering in all three years (Table 1c; Fig. 2b). We
found no support for nonlinear selection on leaf-out or first flowering
day in any of the study years.
The estimate of direct selection on leaf-out in 2014 was just outside
the BCa interval for the corresponding estimate of total selection,
suggesting that selection for earlier leaf-out 2014 acted largely via
first flowering day (Table 1a,c). The estimates of total and direct
selection on leaf-out day in 2013 and 2015, and on first flowering day
in all years, did not differ significantly (Table 1b; Fig. 2).
Individuals with shorter development time between leaf-out and first
flowering day had higher fitness than individuals with longer
development time in 2014 and 2015, but not in 2013 (Appendix S7, Table
S1; Fig. 2c). We found no evidence of correlational selection on
leaf-out and first flowering day in any of the three study years (Table
1c).