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

Abstract

Background Individuals within the same species often differ in their metabolic rates, which may covary with behavioural traits (such as exploration), that are consistent across time and/or contexts, and morphological traits. Yet, despite the frequent occurrence of sexual dimorphisms in morphology and behaviour, few studies have assessed whether and how sexes differ in metabolic trait covariances. Methods We investigated sex-specific relationships among resting or active metabolic rate (RMR and AMR, respectively) with exploratory behaviour, measured independently of metabolic rate in a novel environment, body size and body mass, in Carabus hortensis ground beetles. Results RMR, AMR and exploratory behaviour were repeatable among individuals across time, except for male RMR which was unrepeatable. Female RMR neither correlated with exploratory behaviour nor body size/body mass. In contrast, AMR was correlated with both body size and exploratory behaviour. Males with larger body sizes had higher AMR, whereas females with larger body sizes had lower AMR. Both male and female AMR were significantly related to exploratory behaviour, though the relationships between AMR and exploration were body mass-dependent in males and temperature-dependent in females. Discussion Differences between sexes exist in the covariances between metabolic rate, body size and exploratory behaviour. This suggests that selection acts differently on males and females to produce these trait covariances with potentially important consequences for individual fitness.

Is personality and its association with energetics sex‐specific in yellow‐necked mice Apodemus flavicollis?

“…The relationship between MR and risk‐taking behavior in Australian field crickets Teleogryllus oceanicus was found negative in females, whereas no clear association between all traits was found in males (Moschilla et al, 2019 ). In the study on ground beetles, Carabus hortensis done by Yarwood et al ( 2021 ) both male and female active MR was slightly positively related to exploratory behavior. However, the relationships between active MR and exploration were m b dependent in males and temperature dependent in females indicating the different source of this association (Yarwood et al, 2021 ).…”

“…In the study on ground beetles, Carabus hortensis done by Yarwood et al ( 2021 ) both male and female active MR was slightly positively related to exploratory behavior. However, the relationships between active MR and exploration were m b dependent in males and temperature dependent in females indicating the different source of this association (Yarwood et al, 2021 ). Videlier et al ( 2019 ) showed a positive association between SMR and proactivity in male fruit flies Drosophilla melanogaster , whereas any association was absent in females.…”

“…Despite the numerous studies aimed at testing the relationship between personality traits and metabolism (Mathot et al, 2019 ), such covariations have rarely been analyzed assuming a sex‐specific POLS (Hämäläinen et al, 2018 ). Nonetheless, few studies indicate that the correlation between personality traits and physiology can differ between sexes in rodents (Lantová et al, 2011 ; Šíchová et al, 2014 ), birds (Bouwhuis et al, 2014 ), fishes (Methling et al, 2020 ), as well as in invertebrates (Moschilla et al, 2019 ; Videlier et al, 2019 , 2021 ; Yarwood et al, 2021 ). This suggests that testing POLS hypotheses and associated trade‐offs should take into account the plausible sexual conflict (Chapman et al, 2003 ; Wedell et al, 2006 ), which is associated with different selection acting on male and female life‐histories, energetics, and behavior.…”

“…This suggests that sexual dimorphism should also be seen in the covariation between traits that leads to the evolution of sex‐specific POLS (Hämäläinen et al, 2018 ). Although only occasionally studied, the sex‐specific correlation between physiology and personality was found to exist in invertebrates (Moschilla et al, 2019 ; Videlier et al, 2019 , 2021 ; Yarwood et al, 2021 ). Also, several studies found a similar phenomenon in vertebrates, for example, rodents (Lantová et al, 2011 ; Šíchová et al, 2014 ), birds (Bouwhuis et al, 2014 ), and fishes (Methling et al, 2020 ).…”

Temperature change exerts sex-specific effects on behavioural variation

“…Interestingly, the mass-dependence of thermal acclimation capacity was associated with modest sex differences in thermal plasticity within species that exhibited sexual size dimorphism-potentially due to heavier organisms having greater thermal inertia in response to temperature change [27]. Moreover, males and females have also been shown to differ in their relationship between physiology and behaviour [29][30][31], suggesting that temperatureinduced effects on physiological traits may exert sex-specific effects on behaviour. However, whether the effects of temperature on individual-level variation are sex-specific remains largely uninvestigated.…”