On the usage of single measurements in behavioural ecology research on individual differences

Since the early 21st century, behavioural ecologists have increasingly focused on the ecology and evolution of repeatable individual differences in behaviour (aka ‘animal personality’). More and more studies have investigated correlations between behaviour(s) and other phenotypic traits, thereby seeking to understand among-individual variation in behaviour from either a proximate or an ultimate perspective. Statistically, such studies require...