Data from: An approach to estimate short-term, long-term, and reaction norm repeatability

Evolutionary ecologists increasingly study reaction norms that are
expressed repeatedly within the same individual's lifetime. For
example, foragers continuously alter anti-predator vigilance in response
to moment-to-moment changes in predation risk. Variation in this form of
plasticity occurs both among and within individuals. Among-individual
variation in plasticity (individual by environment interaction or I×E) is
commonly studied; by contrast, despite increasing interest in its
evolution and ecology, within-individual variation in phenotypic
plasticity is not. We outline a study design based on repeated measures
and a multi-level extension of random regression models that enables
quantification of variation in reaction norms at different hierarchical
levels (such as among- and within-individuals). The approach enables the
calculation of repeatability of reaction norm intercepts (average
phenotype) and slopes (level of phenotypic plasticity); these indices are
not specific to measurement or scaling and are readily comparable across
data sets. The proposed study design also enables calculation of
repeatability at different temporal scales (such as short- and long-term
repeatability) thereby answering calls for the development of approaches
enabling scale-dependent repeatability calculations. We introduce a
simulation package in the R statistical language to assess power,
imprecision and bias for multi-level random regression that may be
utilised for realistic datasets (unequal sample sizes across individuals,
missing data, etc). We apply the idea to a worked example to illustrate
its utility. We conclude that consideration of multi-level variation in
reaction norms deepens our understanding of the hierarchical structuring
of labile characters and helps reveal the biology in heterogeneous
patterns of within-individual variance that would otherwise remain
‘unexplained’ residual variance.