EVIDENCE FOR STABILIZING SELECTION AND SLOW DIVERGENT EVOLUTION OF MALE GENITALIA IN A MILLIPEDE (ANTICHIROPUS VARIABILIS)
Version of Record online: 6 DEC 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 66, Issue 4, pages 1138–1153, April 2012
How to Cite
Wojcieszek, J. M. and Simmons, L. W. (2012), EVIDENCE FOR STABILIZING SELECTION AND SLOW DIVERGENT EVOLUTION OF MALE GENITALIA IN A MILLIPEDE (ANTICHIROPUS VARIABILIS). Evolution, 66: 1138–1153. doi: 10.1111/j.1558-5646.2011.01509.x
- Issue online: 6 APR 2012
- Version of Record online: 6 DEC 2011
- Accepted manuscript online: 15 NOV 2011 12:50AM EST
- Received December 28, 2010, Accepted October 29, 2011
- genital morphology;
- sexual selection;
- stabilizing selection
It is generally accepted that postcopulatory sexual selection drives rapid divergence of genital morphology among isolated populations. The mode of selection operating upon genitalia can be explored by comparing patterns of population divergence in genetic and genitalic traits. We collected Antichiropus variabilis millipedes from eight localities across the species range. Levels of among-population genetic divergence, at microsatellite loci, and the mitochondrial COI gene were very high. Following geometric morphometric analyses, genital morphology was also found to be highly divergent among the populations surveyed, whereas head morphology had not diverged as markedly. However, pairwise comparisons of FST and PST showed that among-population divergence in both genital and head shape was significantly lower than that experienced by neutral genetic markers. Our results suggest that the genitalia of A. variabilis are currently experiencing a period of stabilizing selection, the mode of selection expected for genitalia that function in species recognition via a “lock-and-key” mechanism. Our results demonstrate that although genital morphology can clearly diverge among genetically isolated populations, divergence is not necessarily as rapid as commonly argued, and continuous directional sexual selection may not always underpin the evolutionary divergence of male genitalia.