The Conundrum of Heterogeneities in Life History Studies.
What causes interindividual variation in fitness? Evidence of heritability of latent individual fitness traits has resparked a debate about the causes of variation in life histories in populations: neutralism versus empirical adaptationism. This debate about the processes underlying observed variation pits neutral stochastic demographic processes against evolutionarily relevant differences among individual fitness traits. Advancing this debate requires careful consideration of differences among inference approaches used by proponents of each hypothesis. Here we draw parallels between several disciplines focusing on processes generating variation in individuals' life-course, and we contrast methodologies to disentangle these processes. We draw on other disciplines to clarify terminology, risks of flawed inference, and expand the panel of hypotheses and formalizations of processes generating variation in life histories.
Laboratoire Évolution et Diversité Biologique, UMR 5174: Université Toulouse III, CNRS, ENFA, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France. Electronic address: emmanuelle.cam@univ-tlse3.fr.
Emmanuelle
E
Cam
Department of Wildland Resources and the Ecology Center, 5230 Old Main Hill, Utah State University, Logan, UT 84322-5230, USA.
Lise M
LM
Aubry
Observatoire PELAGIS, Centre de Recherche sur les Mammifères Marins, UMS 3462, Pôle Analytique, 5 Allée de l'Océan, Université La Rochelle, 17000 La Rochelle, France.
Matthieu
M
Authier
D000818:Animals; D003710:Demography; D006801:Humans; D008018:Life Cycle Stages; D010641:Phenotype; D013269:Stochastic Processes
latent traits; life history evolution; neutral model; state-dependence; stochasticity; unobserved heterogeneity