gives the instantaneous variance of the Brownian process (evolutionary rate) for the ith trait and jth regime. Note that this is a different use of subscripts as compared to Eq. (1) in which only traits, and not regimes, were being indicated. rj gives the evolutionary correlation between traits 1 and 2 for evolutionary regime j. In the table, regime 1 is non-piscivory and regime 2 is piscivorous feeding mode, while trait 1 is relative gape width and trait 2 is relative buccal length (Fig. 1). The best-supported model using AIC as our model selection criterion, highlighted in bold font, is model 3c: different rates for trait 2, different correlations.