Figure 1.
Comparison between (a) the phenotype fitness function, and (b) genotype fitness function relative to the trait variation (after Martin and Huey [27]).
Because of the steep part (cliff) of function (a), the optimal trait value (red phenotypic distribution) is shifted downwards from the trait value that maximizes phenotype fitness. Function (c) represents the variance in offspring phenotype fitness for different mean values of the trait.
Figure 2.
Effect of phenotypic variance on optimal litter size in Guinea pigs.
(a) Asymmetric fitness function b(L)/m(L). The curve reaches its maximum value on the plateau between L = 2 and L = 3. The dashed line corresponds to the optimal genotype L = 3.05 (σ = 1.14) that best fits the empirical data from Mountford [20]. (b) Position of the optimal genotype relative to the standard deviation σ.
Figure 3.
Comparison between model predictions (dashed line) and empirical data (Mountford [20], solid line) for the distribution of litter sizes in the population.
The model predicts an optimal genotypic value for litter size at 3.05 with a variance σ2 of 1.30.
Figure 4.
Estimate of the asymmetric phenotype fitness function z for Calopteryx splendens in relation with wing patch length x.
The maximum is reached for a wing patch length of 17.52 mm. The dashed line represents the optimal genotype predicted by our model that best fits the observed population distribution, i.e. a patch length of 16.93 mm.
Figure 5.
Distribution of wing patch length of Calopteryx splendens at the population Naturreservat Klingavälsån (55.6384, 13.54142) in southern Sweden.
The bars correspond to males caught in the field. The line shows the distribution predicted by the model with an optimal patch length of 16.93 mm and a standard deviation of 2 mm.
Figure 6.
Model of the distal part of the bronchial tree used in this study.
After each bifurcation the generation index is incremented by one (white numbers). The full model consists of 11 generations.
Figure 7.
Relationship between homothetical factor h and fitness (trade-off between lung volume and hydrodynamical resistance).
The vertical dashed line corresponds to the optimal genotype h = 0.8504 with σ = 0.2, which best fits empirical data.