A multivariate approach to the analysis of within lifetime variation in life history


life-history evolution, phenotypic plasticity, Nicrophorus, Poeciliidae, multivariate trajectory


  1. Ecological and environmental gradients create varying selective pressures on organisms that result in differences in optimal life history tactics. Moreover, life histories are inherently multivariate, consisting of a coordinated suite of life history traits that vary over an organism's lifetime. Such variation can be described as a trajectory of phenotypic change through time in multivariate space defined by a set of life history traits.
  2. We demonstrate the use of phenotypic trajectory analysis as a multivariate analytical approach for quantifying and comparing phenotypic change in life history throughout an organism's life. Life history trajectories have attributes – magnitude, direction, and shape – that can be quantified and statistically compared. We demonstrate the construction of trajectories using levels characterized by individuals with the same age or similar state, and we show how this approach can be used to evaluate the evolution of life history strategies given predictions from life history theory.
  3. We demonstrate the utility of phenotypic trajectory analysis for life histories using two examples. We compare life history trajectories of burying beetles and show that females balance costs of reproduction differently based on resource availability. We also characterize life history trajectories of livebearing fish in different predation environments. We show that females in non-predator environments, but not predator environments, exhibit trajectories consistent with the terminal investment hypothesis.
  4. While analysing life history variation in a multivariate framework is not novel, we show that phenotypic trajectory analysis provides a method to statistically test age- and state-based predictions of life history theory.

Original Publication Citation

Billman, EJ, JE Rasmussen, JC Creighton, JB Johnson, and MC Belk. 2014. A multivariate approach to the analysis of within lifetime variation in life history. Methods in Ecology and Evolution 5:797-805.

Document Type

Peer-Reviewed Article

Publication Date


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Methods in Ecology and Evolution




Life Sciences



University Standing at Time of Publication

Full Professor