Selection, structure and the heritability of behaviour

Abstract

Characters which are closely linked to fitness often have low heritabilities (VA/VP). Low heritabilities could be because of low additive genetic variation (VA), that had been depleted by directional selection. Alternatively, low heritabilities may be caused by large residual variation (VR=VP – VA) compounded at a disproportionately higher rate than VA across integrated characters. Both hypotheses assume that each component of quantitative variation has an independent effect on heritability. However, VA and VR may also covary, in which case differences in heritability cannot be fully explained by the independent effects of elimination‐selection or compounded residual variation. We compared the central tendency of published behavioural heritabilities (mean=0.31, median=0.23) with morphological and life history data collected by Mousseau & Roff (1987). Average behavioural heritability was not significantly different from average life history heritability, but both were smaller than average morphological heritability. We cross‐classified behavioural traits to test whether variation in heritability was related to selection (dominance, domestic/wild) or variance compounding (integration level). There was a significant three‐way interaction between indices of selection and variance compounding, related to the absence of either effect at the highest integration level. At lower integration levels, high dominance variance indicated effects of selection. It was also indicated by the low CVA of domestic species. At the same time CVR increased disproportionately faster than CVA across integration levels, demonstrating variance compounding. However, neither CVR nor CVA had a predominant effect on heritability. The partial regression coefficients of CVR and CVA on heritability were similar and a path analysis indicated that their (positive) correlation was also necessary to explain variation in heritability. These results suggest that relationships between additive genetic and residual components of quantitative genetic variation can constrain their independent direct effects on behavioural heritability.

‘Heritability’ of dispersal propensity in a patchy population

“…Typical values for heritability of behavioural traits are 0.20-0.40, with a mean value of 0.30G0.03 for traits linked to movement (see review in Stirling et al 2002). Even when taking environmental effects into account, our estimates of heritability of dispersal propensity based on a large dataset are probably close to this general value and within the range of observed values recently obtained by other studies for dispersal traits (Hansson et al 2003;McCleery et al 2004;Pasinelli et al 2004;review in Doligez & Pärt 2008).…”

Genetic and maternal effect influences on viability of common frog tadpoles under different environmental conditions

“…In what follows, we will discuss the implications of each of these findings in turn, and, in particular, in the context of the current debate on the heritability of different types of traits under different environmental conditions. A general picture emerging from studies of wild animal populations is that the closer association a trait has with fitness, the lower its heritability is likely to be (Mousseau and Roff, 1987;Houle, 1992;Merilä andSheldon, 1999, 2000;Kruuk et al, 2000;Stirling et al, 2002). The results of the present study conform to this general pattern: all four fitness-associated traits were significantly heritable, but the heritabilities were low.…”

Heterospecific Nest Site Copying Behavior in a Wild Bird: Assessing the Influence of Genetics and Past Experience on a Joint Breeding Phenotype

“…Reproductive decisions are thought to be highly plastic in response to environmental variations (Lynch and Walsh, 1998;Meffert et al, 2002;Stirling et al, 2002). Consequently, heritability estimates of behaviors linked to reproduction are usually relatively low to moderate (on average 0.3; Stirling et al, 2002).…”