Metabolic Scope as a Proximate Constraint on Individual Behavioral Variation: Effects on Personality, Plasticity, and Predictability

Abstract

Behavioral ecologists have hypothesized that among-individual differences in resting metabolic rate (RMR) may predict consistent individual differences in mean values for costly behaviors or for behaviors that affect energy intake rate. This hypothesis has empirical support and presently attracts considerable attention, but, notably, it does not provide predictions for individual differences in (a) behavioral plasticity or (b) unexplained variation (residual variation from mean individual behavior, here termed predictability). We outline how consideration of aerobic maximum metabolic rate (MMR) and particularly aerobic scope (= MMR - RMR) can be used to simultaneously make predictions about mean and among- and within-individual variation in behavior. We predict that while RMR should be proportional to an individual's mean level of sustained behavioral activity (one aspect of its personality), individuals with greater aerobic scope will also have greater scope to express behavioral plasticity and/or greater unpredictability in behavior (=greater residual variation). As a first step toward testing these predictions, we analyze existing activity data from selectively bred lines of mice that differ in both daily activity and aerobic scope. We find that replicate high-scope mice are more active on average and show greater among-individual variation in activity, greater among-individual variation in plasticity, and greater unpredictability. These data provide some tentative first support for our hypothesis, suggesting that further research on this topic would be valuable.

Peer Review #2 of "Covariations between personality behaviors and metabolic/performance traits in an Asian agamid lizard (Phrynocephalus vlangalii) (v0.2)"

“…Because we found no correlation between body size (SVL or body mass) with endurance ability in P. vlangalii, the association between exploration intensity and endurance ability seems more likely mediated by its association with metabolic capacity. A recent study reporting that maximal oxygen consumption/metabolic scope constrain individual behavioral variation supports this idea (Biro et al 2018), although the correlation SMR and endurance ability was absent in this study. It is also worth noting that body mass but not the SVL of male P. vangalii is marginally correlated with risk-taking intensity, suggesting individuals with better body conditions are willing to take more risk during foraging or mate searching since they are less vulnerable to predation (Mayer et al 2016).…”

Spontaneous activity rates and resting metabolism: Support for the allocation model of energy management at the among‐individual level

“…This is a seemingly rare observation in the literature given that most correlations are very low but in the positive direction, whereas very few studies show evidence of a negative correlation (Careau, Beauchamp, Bouchard, & Morand‐Ferron, ; Krams et al, , ; Royauté et al, ). Given that the observed negative covariance between RMR and activity did not match our expectations under the performance model, this suggests that activity and underlying metabolic variation are not always linked together in ways as predicted by the majority of recent theoretical advances in this area (Biro et al, ; Biro & Stamps, , ; Burton et al, ; Réale et al, ; Sih & Bell, ).…”

“…suggests that activity and underlying metabolic variation are not always linked together in ways as predicted by the majority of recent theoretical advances in this area (Biro et al, 2018;Biro & Stamps, 2008Burton et al, 2011;Réale et al, 2010;Sih & Bell, 2008).…”

Ecological and evolutionary consequences of metabolic rate plasticity in response to environmental change

“…One possibility is that this plasticity constrains or covaries with plasticity in other key organismal traits [100]. For instance, while a range of physiological traits (metabolic rate, haematocrit, corticosterone and immune function) can apparently change independently of one another [85], metabolic rate may constrain plasticity in behaviour [101]. Given the importance of behaviour for responding to a changing environment [102,103], investigations are needed of the links between metabolic and behavioural plasticity.…”