Current address: Department of Biological Sciences, University of Notre Dame, Galvin Life Sciences Building, Notre Dame, Indiana 46556.
NATURAL SELECTION ON GALL SIZE: VARIABLE CONTRIBUTIONS OF INDIVIDUAL HOST PLANTS TO POPULATION-WIDE PATTERNS
Article first published online: 21 JUL 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 65, Issue 12, pages 3543–3557, December 2011
How to Cite
Egan, S. P., Hood, G. R. and Ott, J. R. (2011), NATURAL SELECTION ON GALL SIZE: VARIABLE CONTRIBUTIONS OF INDIVIDUAL HOST PLANTS TO POPULATION-WIDE PATTERNS. Evolution, 65: 3543–3557. doi: 10.1111/j.1558-5646.2011.01396.x
- Issue published online: 1 DEC 2011
- Article first published online: 21 JUL 2011
- Accepted manuscript online: 5 JUL 2011 04:18PM EST
- Received August 24, 2010, Accepted June 16, 2011, Data Archived: Dryad, doi:10.5061/dryad.1js1n
- gall former;
- local adaptation;
- selection gradients;
- spatial and temporal variation
Studies that provide estimates of the form and magnitude of selection on herbivore traits at the level of individual plants in natural populations represent a vital step in understanding the interaction of selection and gene flow among host-affiliated insect populations when individual plants equate to differing selective regimes. We analyzed phenotypic selection on the trait gall size for a host-specific gall former at both the individual host plant and population level (across host plants) in each of two years. Linear and nonlinear selection and the fitness function relating gall size to the probability of survivorship in the absence of natural enemies were estimated for each level and year. Selection imposed by the host plant was observed in 19 of the 22 subpopulations monitored. At the population level, linear and nonlinear selection were evident each year. However, population-level estimates masked the significant heterogeneity in the form and direction of selection evident among plants each year. Heterogeneity among gall-former subpopulations is emphasized by our findings that selection varied from directional to stabilizing among plants and the majority of selection gradients estimated for individual plants did not fall within the 95% CIs of the population-level estimates.