title: Sex allocation in California oaks: trade-offs or resource tracking?
abstract: Trade-offs in sex resource allocation are commonly inferred from a negative correlation between male and female reproduction. We found that for three California oak species, aboveground annual net productivity (ANP) differences among individuals were primarily correlated with water availability and soil fertility. Reproductive biomass increased with ANP, but the relative allocation to reproduction was constant, indicating that reproduction tracked productivity, which in turn tracked site quality. Although there was a negative correlation between male and female reproduction, this was not the result of a resource investment trade-off, but rather a byproduct of the positive correlation between female reproductive biomass and ANP combined with the greater overall resource allocation to female, compared to male, function. Thus, we reject the hypothesis of a trade-off between these key life-history components within individuals of these species. For long-lived individuals, a plastic resource tracking response to environmental fluctuations may be more adaptive than directly linking life-history traits through trade-offs.
authors.affiliation: School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America. jknops2@unl.edu
authors.forename: Johannes M H
authors.initials: JM
authors.lastname: Knops
authors.forename: Walter D
authors.initials: WD
authors.lastname: Koenig
mesh_terms: D005075:Biological Evolution; D018533:Biomass; D002140:California; D004777:Environment; D008957:Models, Genetic; D010641:Phenotype; D018521:Plant Physiological Phenomena; D029963:Quercus / Q000235:genetics*; D012098:Reproduction / Q000502:physiology; D012987:Soil; D014867:Water
chemical_list: D012987:Soil; D014867:Water