Fig 4. Phenotypic variance and integration across the species' niche as captured by the temperature gradient.
The three panels represent different features of the so-called phenotypic G matrix (i.e. the traits genetic variances and co-variances). (a) The relation between G's volume (i.e. total genetic variance) per population and the temperature gradient. (b) The relationship between G's shape (proportion of variance explained by Pmax) and the temperature gradient. (c) The relationship between the population potential response to selection toward colder and low levels of solar radiation, and two regional niche axes: temperature (in °C) and solar radiation (in kWH/m2; only considering population of the coldest half of the gradient). The size of the dots represents the mean absolute trait displacement after application of the Selection Skewer Method, and the red arrow indicates the direction of the applied selection vector.