Pace-of-life syndromes: a framework for the adaptive integration of behaviour, physiology and life history

Abstract

This introduction to the topical collection on Pace-of-life syndromes: a framework for the adaptive integration of behaviour, physiology, and life history provides an overview of conceptual, theoretical, methodological, and empirical progress in research on pace-of-life syndromes (POLSs) over the last decade. The topical collection has two main goals. First, we briefly describe the history of POLS research and provide a refined definition of POLS that is applicable to various key levels of variation (genetic, individual, population, species). Second, we summarise the main lessons learned from current POLS research included in this topical collection. Based on an assessment of the current state of the theoretical foundations and the empirical support of the POLS hypothesis, we propose (i) conceptual refinements of theory, particularly with respect to the role of ecology in the evolution of (sexual dimorphism in) POLS, and (ii) methodological and statistical approaches to the study of POLS at all major levels of variation. This topical collection further holds (iii) key empirical examples demonstrating how POLS structures may be studied in wild populations of (non)human animals, and (iv) a modelling paper predicting POLS under various ecological conditions. Future POLS research will profit from the development of more explicit theoretical models and stringent empirical tests of model assumptions and predictions, increased focus on how ecology shapes (sex-specific) POLS structures at multiple hierarchical levels, and the usage of appropriate statistical tests and study designs. Significance statementAs an introduction to the topical collection, we summarise current conceptual, theoretical, methodological and empirical progress in research on pace-of-life syndromes (POLSs), a framework for the adaptive integration of behaviour, physiology and life history at multiple hierarchical levels of variation (genetic, individual, population, species). Mixed empirical support of POLSs, particularly at the within-species level, calls for an evaluation and refinement of the hypothesis. We provide a refined definition of POLSs facilitating testable predictions. Future research on POLSs will profit from the development of more explicit theoretical models and stringent empirical tests of model assumptions and predictions, increased focus on how ecology shapes (sex-specific) POLSs structures at multiple hierarchical levels and the usage of appropriate statistical tests and study designs.

Size‐selective harvesting fosters adaptations in mating behaviour and reproductive allocation, affecting sexual selection in fish

“…In contrast to expectations, male aggression increased in both size‐selected lines and did not diverge as a result of the opposing directional size selection. The increased aggression by males of the large‐harvested line agrees with the pace‐of‐life hypothesis (Dammhahn et al, ; Réale et al, ). Accordingly, the fast life history is selected to reap fitness benefits early in life, such that males of the large‐harvested line become more aggressive than controls, which has previously been shown to enhance reproductive success in zebrafish (Ariyomo & Watt, ; Vargas et al, ).…”

Sex differences in life history, behavior, and physiology along a slow-fast continuum: a meta-analysis

“…Surprisingly, we found that adult life-history deviates from all the other trait categories (behavior, physiology and developmental life-history), which all cluster together along the fast-slow POL continuum. In the POLS hypothesis, life history traits play a key role because the framework aims to predict how individuals and sexes mediate the trade-off between current and future reproduction (Dammhahn et al 2018, topical collection on Pace-of-life syndromes). Thus, life history traits must always be included in studies investigating POLS.…”

A scale‐dependent framework for trade‐offs, syndromes, and specialization in organismal biology

“…The LES was codified as the trade-off between resource-conservative and -acquisitive strategies for leaves, most typically observed as a pattern across distantly related species (Fig. This search for generality and expansion of predictions is certainly not unique to plant ecology; for example, this has been recently seen in the animal literature on the pace-of-life hypothesis (Dammhahn et al 2018). Resource-conservative species tend to have lower photosynthetic and dark respiration rates, lower nitrogen and phosphorous contents, longer leaf lifespans, and higher leaf mass per area (LMA), whereas acquisitive species tend to have the opposite suite of trait values.…”