INTERSPECIFIC COMPETITION ALTERS NONLINEAR SELECTION ON OFFSPRING SIZE IN THE FIELD
Version of Record online: 22 AUG 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 67, Issue 2, pages 328–337, February 2013
How to Cite
Marshall, D. J. and Monro, K. (2013), INTERSPECIFIC COMPETITION ALTERS NONLINEAR SELECTION ON OFFSPRING SIZE IN THE FIELD. Evolution, 67: 328–337. doi: 10.1111/j.1558-5646.2012.01749.x
- Issue online: 28 JAN 2013
- Version of Record online: 22 AUG 2012
- Accepted manuscript online: 1 AUG 2012 12:56PM EST
- Received August 18, 2011 Accepted July 16, 2012 Data Archived: Dryad doi:10.5061/dryad.d6v18
- Egg size;
- life-history evolution;
- maternal effect
Offspring size is one of the most important life-history traits with consequences for both the ecology and evolution of most organisms. Surprisingly, formal estimates of selection on offspring size are rare, and the degree to which selection (particularly nonlinear selection) varies among environments remains poorly explored. We estimate linear and nonlinear selection on offspring size, module size, and senescence rate for a sessile marine invertebrate in the field under three different intensities of interspecific competition. The intensity of competition strongly modified the strength and form of selection acting on offspring size. We found evidence for differences in nonlinear selection across the three environments. Our results suggest that the fitness returns of a given offspring size depend simultaneously on their environmental context, and on the context of other offspring traits. Offspring size effects can be more pervasive with regards to their influence on the fitness returns of other traits than previously recognized, and we suggest that the evolution of offspring size cannot be understood in isolation from other traits. Overall, variability in the form and strength of selection on offspring size in nature may reduce the efficacy of selection on offspring size and maintain variation in this trait.