Ecological conditions drive pace-of-life syndromes by shaping relationships between life history, physiology and behaviour in two populations of Eastern mosquitofish

Abstract

The pace-of-life syndrome (POLS) hypothesis predicts variation in behaviour and physiology among individuals to be associated with variation in life history. Thus, individuals on the “fast” end of POLS continuum grow faster, exhibit higher metabolism, are more risk prone, but die earlier than ones on the “slow” end. Empirical support is nevertheless mixed and modelling studies suggested POLS to vary along selection gradients. Therefore, including ecological variation when testing POLS is vastly needed to determine whether POLS is a fixed construct or the result of specific selection processes. Here, we tested POLS predictions between and within two fish populations originating from different ecological conditions. We observed opposing life histories between populations, characterized by differential investments into growth, fecundity, and functional morphology under identical laboratory conditions. A slower life history was, on average, associated with boldness (latency to emergence from a refuge), high activity (short freezing time and long distance travelled), and increased standard metabolism. Correlation structures among POLS traits were not consistent between populations, with the expression of POLS observed in the slow-growing but not in the fast-growing population. Our results suggest that POLS traits can evolve independently from one another and that their coevolution depends upon specific ecological processes.

Experimental Size‐Selective Harvesting Affects Behavioral Types of a Social Fish

“…Our work underscores that the predictions of the pace‐of‐life hypothesis with respect to personality and life history correlations can be context dependent and can vary among ecological conditions, thereby complicating generalizations (Polverino et al. ; Royauté et al. ; Wright et al.…”

Environmental effects on the covariation among pace‐of‐life traits

“…The effects of predictability or stochasticity of the environment on POLS has not been directly addressed, but some evidence indicates a potential for unpredictability to contribute to the effects of an unfavourable environment. Polverino, Santostefano, Díaz-Gil, & Mehner (2018) found distinctly different POLS-trait covariance structures in lab-reared mosquitofish that originated from a stable (possibly more favourable) habitat, relative to fish from a harsher, unpredictable source habitat. While the study supports the hypothesis in that POLS was found only under the more predictable environment, the direction of the trait correlations were opposite to those predicted: the fish sourced from the more predictable environment expressed a slower POL relative to fish from the unpredictable habitat, but their slower POL was associated with higher metabolic maintenance costs, higher activity and boldness.…”

Harvesting-induced evolution of collective risk-taking behavior and changes to the circadian system in a fish

“…In fact, we demonstrated an adaptive behavioral link between boldness and daily activity rhythms in the small-, but not in the large-, harvested line. Fisheries-induced evolution of behavior likely has a complex and multivariate nature (9, 21), thereby complicating generalizations related to evolutionary correlations among traits (45-47). The somewhat asymmetrical adaptation of behavior in the two size-selection lines did not extend to all traits that we measured, which could be related to a functional limitation of the range of evolution of our model species (21, 48).…”