Abstract
The recent interest in animal personality has sparked a number of studies on the heritability of personality traits. Yet, how the sources variance these traits can be decomposed remains unclear. Moreover, whether genetic correlations with life-history traits, personality traits and other phenotypic traits exist as predicted by the pace-of-life syndrome hypothesis remains poorly understood. Our aim was to compare the heritability of personality, life-history and morphological traits and their potential genetic correlations in a small primate (Microcebus murinus). We performed an animal model analysis on six traits measured in a large sample of captive mouse lemurs (N = 486). We chose two personality traits, two life-history traits and two morphological traits to (i) estimate the genetic and/or environmental contribution to their variance, and (ii) test for genetic correlations between these traits. We found modest narrow-sense heritability for personality traits, morphological traits and life-history traits. Other factors including maternal effects also influence the sources of variation in life-history and morphological traits. We found genetic correlations between emergence latency on the one hand and radius length and growth rate on the other hand. Emergence latency was also genetically correlated with birth weight and was influenced by maternal identity. These results provide insights into the influence of genes and maternal effects on the partitioning of sources of variation in personality, life-history and morphological traits in a captive primate model and suggest that the pace-of-life syndrome may be partly explained by genetic trait covariances.
Highlights
In his most famous publication, Charles Darwin noted how selection on dogs and pigeons led to the appearance of correlations between traits [1]: hairless dogs frequently showing tooth problems and pigeons with feathered legs having skin between their toes
We found significant additive genetic variances for radius length, emergence latency and our agitation score
The agitation score during handling has previously been suggested to be associated with shyness and anxiety [32,42], emergence latency on the other hand has been suggested to be linked to exploration [32]. We found that both traits showed significant additive genetic variance and medium heritability (0.19–0.22)
Summary
In his most famous publication, Charles Darwin noted how selection on dogs and pigeons led to the appearance of correlations between traits [1]: hairless dogs frequently showing tooth problems and pigeons with feathered legs having skin between their toes. A general theoretical framework to understand the relationship between various phenotypic traits and life-history traits is the pace-of-life syndrome [3], in which behaviour and personality have been recently included [4,5]. This concept links phenotypic traits based on a slow–fast continuum in the ‘pace-of-life’ of the organism. Individuals are expected to present a bolder and more active personality and a higher metabolic rate and growth rate in relation to a fast pace-of-life (e.g. small rodents) Under this theory, behaviour and life history could be mediated by hormonal determinants [3], yet may be linked in other ways
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