Data from: Evolution and plasticity: divergence of song discrimination is faster in birds with innate song than in song learners in Neotropical passerine birds

We tested these predictions by analyzing acoustic traits and conducting playback experiments in allopatric Central American sister pairs of song learning oscines (N = 42) and non-learning suboscines (N = 27). We found that non-learners evolved mean acoustic differences slightly faster than did leaners, and that the mean evolutionary rate of song discrimination was 4.3 times faster in non-learners than in learners. This unexpected result may be a consequence of significantly greater variability in song traits in song learners (by 54–79%) that requires song-learning oscines to evolve greater absolute differences in song before achieving the same level of behavioral song discrimination as non-learning suboscines.

This points to “a downside of learning” for the evolution of species discrimination, and represents an important example of plasticity reducing the rate of evolution and diversification by increasing variability.

Usage notes

TableS1_datatable This data table provides the data necessary to recreate the analyses presented in the Freeman et al. paper in Evolution. The unit of analysis in this study is the "sister pair". Thus, each row in the file provides information for a phylogenetically independent sister pair.

The key columns are: 1) Clade (either suboscine or oscine), 2) Overall_Discrimination (the proportion of territories that discriminated against allopatric song; note that for sister pairs where we conducted reciprocal playbacks (how population A responds to song from population B and also how population B responds to song from population A), this value is the average of each unidirectional comparison), and 3) GeneticDistance (uncorrected p-distance in mtDNA).

TableS1_forDryad.xlsx