Unexpected Nongenetic Individual Heterogeneity and Trait Covariance in Daphnia and Its Consequences for Ecological and Evolutionary Dynamics
Authored by Clayton E Cressler, Stefan Bengtson, William A Nelson
Date Published: 2017
DOI: 10.1086/691779
Sponsors:
National Science and Engineering Research Council of Canada (NSERC)
Platforms:
R
Model Documentation:
Other Narrative
Model Code URLs:
https://www-journals-uchicago-edu.ezproxy1.lib.asu.edu/doi/suppl/10.1086/691779/suppl_file/RCode.zip
Abstract
Individual differences in genetics, age, or environment can cause
tremendous differences in individual life-history traits. This
individual heterogeneity generates demographic heterogeneity at the
population level, which is predicted to have a strong impact on both
ecological and evolutionary dynamics. However, we know surprisingly
little about the sources of individual heterogeneity for particular taxa
or how different sources scale up to impact ecological and evolutionary
dynamics. Here we experimentally study the individual heterogeneity that
emerges from both genetic and nongenetic sources in a species of
freshwater zooplankton across a large gradient of food quality. Despite
the tight control of environment, we still find that the variation from
nongenetic sources is greater than that from genetic sources over a wide
range of food quality and that this variation has strong positive
covariance between growth and reproduction. We evaluate the general
consequences of genetic and nongenetic covariance for ecological and
evolutionary dynamics theoretically and find that increasing nongenetic
variation slows evolution independent of the correlation in heritable
life-history traits but that the impact on ecological dynamics depends
on both nongenetic and genetic covariance. Our results demonstrate that
variation in the relative magnitude of nongenetic versus genetic sources
of variation impacts the predicted ecological and evolutionary dynamics.
Tags
Individual-based model
phenotypic plasticity
Population-growth
Heritability
Size
Age
Nutrient limitation
Demographic
stochasticity
Life-history traits
Magna straus
Demographic heterogeneity
Individual stochasticity
Life-history
covariation
Stoichiometric food quality
Daphnia pulicaria
Clonal variation