The popularity of trait-based approaches continues to rise despite challenges in identifying strong links between traits and organism performance. Here, we summarise evidence demonstrating that not all traits appear to be functional, and discuss how life history theory and demography can help elucidate which, how, where, and when traits gain functionality

Phenotypic plasticity can mask population genetic differentiation, reducing the predictability of trait-environment relationships. In short-lived plants, reproductive traits may be more genetically determined due to their direct impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-treatment greenhouse experiment with global field observations for the short-lived Plantago lanceolata, we 1) disentangled the genetic and plastic responses of functional traits to a set of environmental drivers and 2) assessed the utility of trait-environment relationshisps inferred from observational data for predicting genetic differentiation. Reproductive traits showed distinct genetic differentiation that was highly predictable from observational data, but only when correcting traits for differences in their (labile) biomass component. Vegetative traits showed higher plasticity and contrasting genetic and plastic responses, leading to unpredictable trait patterns. Our study suggests that genetic differentiation may be inferred from observational data only for the traits most closely related with fitness.

A document by Rob Salguero-Gómez. Click on the document to view its contents.

Despite ca. seven decades of theoretical elaboration since Peter Medawar’s foundational ‘An Unsolved Problem of Biology’, we argue that the fundamental problem of the evolution of senescence, i.e. the increasing risk of mortality and decline in reproduction with age after maturity, remains unsolved. Theories of senescence predict the inescapability of senescence, or its universality at least among species with a clear germ-soma barrier. Here, using demographic information for 475 multicellular species, we exemplify the discrepancy between these theoretical predictions and currently available data. We derive age-based trajectories of mortality and reproduction whose form cannot be satisfactorily explained by the theories of senescence, and show that species’ may often display senescence for one fitness component but not the other. We propose that theories of senescence must be extended beyond merely individual chronological age; size, the species’ ecological context, and kin selection may all play hidden, yet integral roles in shaping patterns of senescence.

Despite ca. seven decades of theoretical elaboration since Peter Medawar’s foundational ‘An Unsolved Problem of Biology’, we argue that the fundamental problem of the evolution of senescence, i.e. the increasing risk of mortality and decline in reproduction with age after maturity, remains unsolved. Theories of senescence predict the inescapability of senescence, or its universality at least among species with a clear germ-soma barrier. Here, using demographic information for 475 multicellular species, we exemplify the discrepancy between these theoretical predictions and currently available data. We derive age-based trajectories of mortality and reproduction whose form cannot be satisfactorily explained by the theories of senescence, and show that species’ may often display senescence for one fitness component but not the other. We propose that theories of senescence must be extended beyond merely individual chronological age; size, the species’ ecological context, and kin selection may all play hidden, yet integral roles in shaping patterns of senescence.