A MULTIVARIATE ANALYSIS OF GENETIC VARIATION IN THE ADVERTISEMENT CALL OF THE GRAY TREEFROG, HYLA VERSICOLOR
Article first published online: 13 APR 2014
© 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.
Volume 68, Issue 6, pages 1629–1639, June 2014
How to Cite
Welch, A. M., Smith, M. J. and Gerhardt, H. C. (2014), A MULTIVARIATE ANALYSIS OF GENETIC VARIATION IN THE ADVERTISEMENT CALL OF THE GRAY TREEFROG, HYLA VERSICOLOR. Evolution, 68: 1629–1639. doi: 10.1111/evo.12397
- Issue published online: 3 JUN 2014
- Article first published online: 13 APR 2014
- Accepted manuscript online: 12 MAR 2014 12:38PM EST
- Manuscript Accepted: 20 FEB 2014
- Manuscript Received: 14 SEP 2011
- G matrix;
- genetic constraint;
- multivariate lek paradox;
- sexual selection;
Genetic variation in sexual displays is crucial for an evolutionary response to sexual selection, but can be eroded by strong selection. Identifying the magnitude and sources of additive genetic variance underlying sexually selected traits is thus an important issue in evolutionary biology. We conducted a quantitative genetics experiment with gray treefrogs (Hyla versicolor) to investigate genetic variances and covariances among features of the male advertisement call. Two energetically expensive traits showed significant genetic variation: call duration, expressed as number of pulses per call, and call rate, represented by its inverse, call period. These two properties also showed significant genetic covariance, consistent with an energetic constraint to call production. Combining the genetic variance–covariance matrix with previous estimates of directional sexual selection imposed by female preferences predicts a limited increase in call duration but no change in call rate despite significant selection on both traits. In addition to constraints imposed by the genetic covariance structure, an evolutionary response to sexual selection may also be limited by high energetic costs of long-duration calls and by preferences that act most strongly against very short-duration calls. Meanwhile, the persistence of these preferences could be explained by costs of mating with males with especially unattractive calls.