Individuality in nutritional preferences: a multi-level approach in field crickets

Abstract

Selection may favour individuals of the same population to differ consistently in nutritional preference, for example, because optimal diets covary with morphology or personality. We provided Southern field crickets (Gryllus bimaculatus) with two synthetic food sources (carbohydrates and proteins) and quantified repeatedly how much of each macronutrient was consumed by each individual. We then quantified (i) whether individuals were repeatable in carbohydrate and protein intake rate, (ii) whether an individual’s average daily intake of carbohydrates was correlated with its average daily intake of protein, and (iii) whether short-term changes in intake of carbohydrates coincided with changes in intake of protein within individuals. Intake rates were individually repeatable for both macronutrients. However, individuals differed in their relative daily intake of carbohydrates versus proteins (i.e., ‘nutritional preference’). By contrast, total consumption varied plastically as a function of body weight within individuals. Body weight—but not personality (i.e., aggression, exploration behaviour)—positively predicted nutritional preference at the individual level as large crickets repeatedly consumed a higher carbohydrate to protein ratio compared to small ones. Our finding of level-specific associations between the consumption of distinct nutritional components demonstrates the merit of applying multivariate and multi-level viewpoints to the study of nutritional preference.

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

“…[60]) was 1:1.3. This finding implied that 2-week-old juveniles preferred to eat relatively similar amounts of carbohydrates (mean ± SE: 20 ± 3 mg) versus proteins (15 ± 4 mg; Fig.…”

“…Furthermore, sex- and trait-specificity in effects of nutritional history imply that a fruitful line of future research would focus on the genetic architecture of dietary preferences across sexes, which may be achieved by using multivariate analyses and quantitative genetics analyses [95]. Finally, the integration of the concepts of nutritional ecology and animal personality will provide a major step towards a general understanding of behavioural evolution in changing environments [60]. …”

“…2 in [55]). The tracking software then measured each individual’s total distance moved in the compartment for 10 minutes [55, 60]. The compartment was novel to the crickets, and we essentially quantified how much time individuals spend out of the shelter, exploring the novel environment.…”

“…The focal and opponent identities were randomly assigned after the experiment for statistical analyses. The tracking software measured the duration of attack when the focal individual chased the opponent (within 6 cm) to attack it; this measure represents an appropriate proxy for aggressiveness based on our previous work on this species [60]. …”

An Approach to Distinguish between Plasticity and Non-random Distributions of Behavioral Types Along Urban Gradients in a Wild Passerine Bird

“…At the same time, urbanization seems to drive non-random distributions of behavioral types via mechanisms yet to be revealed. Our study thereby demonstrates the importance of partitioning behavioral variation across hierarchical levels (Han et al, 2016;Moirón et al, 2016;Nicolaus et al, 2016), both in urban and other behavioral ecological studies, and the novel insights that may be gained by doing so.…”