The fast and the curious II: performance, personality, and metabolism in Karoo bush rats

Abstract

Personality traits (e.g., activity, exploration, boldness) are frequently correlated with each other and with various other traits of biological importance. According to the performance, allocation, and independent models of energy management, the relationship between personality traits and resting metabolic rate (RMR) is predicted to be either positive, negative, or nil. As for the relationship between personality traits and locomotor performance, the trait compensation and co-specialisation hypotheses respectively predict a positive and negative relationship. To test for associations between personality, metabolism, and performance, we studied a wild population of Karoo bush rat (Myotomys unisulcatus) in South Africa. During summer 2018 we captured 45 individuals (38 females and 7 males) a total of 293 times and repeatedly measured docility (time spent immobile during a bag test), exploration (distance moved in an open-field test), sprint speed, and RMR. We found a behavioural syndrome in our population, as more docile individuals covered less distance in the exploration test (r±SE=-0.74±0.21). RMR was not correlated with any trait; therefore, the independent energy management model applies in this population. Fast sprinters were less explorative in the novel environment than slow sprinters (r±SE=-0.41±0.21), going against the prediction of the phenotypic compensation hypothesis and suggesting co-specialisation of these traits. A similar result was previously observed in two other rodent species, suggesting that exploratory behaviour and locomotor performance may interact in an additive instead of compensatory way. Given the apparent complexity of the links between performance, behaviour, and metabolism, more studies are needed in order to understand their relationships.

The relationships between toad behaviour, antipredator defences, and spatial and sexual variation in predation pressure

“…In contrast with other bufonids, such as Rhinella marina , whose jumping distance is directly proportional to body length ( Hudson et al, 2020 ), sprint speed of E. calamita is unrelated to body size ( Zamora-Camacho, 2018 ), which allows for a separate evaluation of both parameters. The absence of correlations between speed and the behavioural traits tested as a part of this study is aligned with findings on Zootoca vivipara ( Le Galliard et al, 2013 ) and Phrinocephalus vlangalii lizards ( Chen et al, 2019 ), but not with findings on Myotomis unisulcatus ( Agnani et al, 2020 ) and Tamias striatus rodents ( Newar & Careau, 2018 ). It is worth mentioning that all toads in this sample engaged in flight behaviour.…”

The effects of exploratory behavior on physical activity in a common animal model of human disease, zebrafish (Danio rerio)

“…Novel tank diving variables had stronger positive correlations with the time in swim zone and time spent swimming than open field variables, suggesting that less-anxious fish were more motivated to be in the swim zone. High levels of exploration in the open field test have been associated with increased wheel running in different inbred strains of mice ( Careau et al, 2012 ) and slow sprinters in wild rats ( Agnani et al, 2020 ). In the current study, the relationship between novel tank diving variables and swimming behavior were relatively weak, thus more evidence is needed to further corroborate these findings.…”

Sex-specific covariance between metabolic rate, behaviour and morphology in the ground beetle Carabus hortensis

“…Still, other studies support the independent hypothesis of energy management in that they found no significant relationship between personality and RMR ( e.g. , Bouwhuis et al, 2014 ; Videlier, Rundle & Careau, 2019 ; Agnani et al, 2020 ). Consequently, the relationships between intraspecific RMR, body mass/body size and animal personality traits remain largely unclear.…”