You are what you eat: diet shapes body composition, personality and behavioural stability

Abstract

BackgroundBehavioural phenotypes vary within and among individuals. While early-life experiences have repeatedly been proposed to underpin interactions between these two hierarchical levels, the environmental factors causing such effects remain under-studied. We tested whether an individual’s diet affected both its body composition, average behaviour (thereby causing among-individual variation or ‘personality’) and within-individual variability in behaviour and body weight (thereby causing among-individual differences in residual within-individual variance or ‘stability’), using the Southern field cricket Gryllus bimaculatus as a model. We further asked whether effects of diet on the expression of these variance components were sex-specific.MethodsManipulating both juvenile and adult diet in a full factorial design, individuals were put, in each life-stage, on a diet that was either relatively high in carbohydrates or relatively high in protein. We subsequently measured the expression of multiple behavioural (exploration, aggression and mating activity) and morphological traits (body weight and lipid mass) during adulthood.ResultsDietary history affected both average phenotype and level of within-individual variability: males raised as juveniles on high-protein diets were heavier, more aggressive, more active during mating, and behaviourally less stable, than conspecifics raised on high-carbohydrate diets. Females preferred more protein in their diet compared to males, and dietary history affected average phenotype and within-individual variability in a sex-specific manner: individuals raised on high-protein diets were behaviourally less stable in their aggressiveness but this effect was only present in males. Diet also influenced individual differences in male body weight, but within-individual variance in female body weight.DiscussionThis study thereby provides experimental evidence that dietary history explains both heterogeneous residual within-individual variance (i.e., individual variation in ‘behavioural stability’) and individual differences in average behaviour (i.e., ‘personality’), though dietary effects were notably trait-specific. These findings call for future studies integrating proximate and ultimate perspectives on the role of diet in the evolution of repeatedly expressed traits, such as behaviour and body weight.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0852-4) contains supplementary material, which is available to authorized users.

Increased developmental density decreases the magnitude of indirect genetic effects expressed during agonistic interactions in an insect

“…)) in our analyses (as in e.g., Dingemanse et al. ; Han and Dingemanse , b). This approach resulted in the following six response variables: aggression expressed in (1) nymphs exposed to the low‐density environment, (2) nymphs exposed to the high‐density environment, (3) young adults exposed to the low‐density environment, (4) young adults exposed to the high‐density environment, (5) old adults exposed to the low‐density environment, and (6) old adults exposed to the high‐density environment.…”

“…All details of our assay procedures are described elsewhere (Santostefano et al. ; Han and Dingemanse ). In brief, males were removed from their individual containers and placed in a plastic arena with a removable partition in the middle to create two small rooms (15 × 15 × 10 cm 3 ).…”

Protein deprivation facilitates the independent evolution of behavior and morphology

“…To summarize, in the exploration assays, the tracking software measured each individual's total distance moved in the compartment (15 × 15 × 10 cm) for 10 minutes (Santostefano et al. ; Han and Dingemanse ,c). After the exploration assay, we put one same‐sex opponent (an individual from the stock population) into the compartment and measured the amount of time (duration) that the focal individual chased the opponent over 10 minutes (aggression assay).…”

How past exposure to predation affects personality and behavioural plasticity?

“…Developmental environmental conditions are also known to impact personality (Biro et al 2010;DiRienzo et al 2015;Urszán et al 2015;Han and Dingemanse 2017;Royauté and Dochtermann 2017), i.e. consistent between-individual difference in mean behaviour across time within a single group (e.g.…”