Metabolic rate and foraging behaviour: A mechanistic link across body size and temperature gradients

Abstract

The mechanistic link between metabolic rate and foraging behaviour is a crucial aspect of several energy-based ecological theories. Despite its importance to ecology however, it remains unclear whether and how energy requirements and behavioural patterns are mechanistically connected. Here we aimed to assess how modes of behaviour, in terms of cumulative space use, patch selection and time spent in an experimental resource patchy environment, are influenced by the foragers' metabolic rate (SMR) and its main determinants i.e. body mass and temperature. We tested the individual behavioural patterns and metabolic rates of a model organism, the amphipodGammarus insensibilis, across a range of body masses and temperatures. We demonstrated that body mass and temperature exert a major influence on foraging decisions and space use behaviour via their effects on metabolic rates. Individual cumulative space use was found to scale allometrically with body mass and exponentially with temperature, with patch giving-up time falling as body mass and temperature increased. Moreover, SMR had greater predictive power for behavioural patterns, explaining variation beyond that accounted for by body mass and temperature combined. Our results showed that cumulative space use scaled positively with Mass-and-Temperature-independent SMR (residual). Furthermore, the foraging decisions regarding patch choice and partitioning were strongly related to M-T independent SMR; individuals with higher M-T independent SMR initially preferred the most profitable patch and, as time progressed, abandoned the patch earlier compared to others. Our findings regarding the mechanistic relationship between behavioural patterns and metabolic rate across body mass and temperature shed light on higher-order energy-based ecological processes, with implications in the face of climate change.

Swimming at Increasing Speeds in Steady and Unsteady Flows of Atlantic Salmon Salmo salar: Oxygen Consumption, Locomotory Behaviour and Overall Dynamic Body Acceleration

“…In nature, fish mostly experience unsteady flows, unpredictable alternations of flow velocity and direction [19]. These environmental factors, in addition to temperature, can impact the metabolic rates and behaviour of fish, leading to alterations in behaviour [26,27] and swimming patterns [22]. But the extent to which it may affect the swimming Further, we used the interaction between swimming speed and flow condition as a covariate in LMM to predict MO 2 using ODBA as the main predictor variable, still accounting for individual variability (Table S1).…”

“…In nature, fish mostly experience unsteady flows, unpredictable alternations of flow velocity and direction [ 19 ]. These environmental factors, in addition to temperature, can impact the metabolic rates and behaviour of fish, leading to alterations in behaviour [ 26 , 27 ] and swimming patterns [ 22 ]. But the extent to which it may affect the swimming performance of post-smolt Atlantic salmon is hardly known.…”

“…Therefore, understanding the swimming behaviour of free-swimming fish in unsteady flows and its correlation with energy expenditure is crucial. This understanding is not only essential for higher-order ecological processes such as ecosystem functioning but also vital for comprehending organism mobility, interactions, and disturbance response patterns as experienced in both natural and controlled environments [ 22 , 26 , 27 ].…”

The relative importance of metabolic rate and body size to space use behavior in aquatic invertebrates

“…Space and resource use behavior differ considerably within and among species which has significant implications in ecological processes, for example, competitive coexistence and consumer‐resource community (Auer et al., 2020 ; Shokri et al., 2024 ). However, despite its importance in ecology and seminal studies drawing attention to this field (e.g., Basset, 1995 ; Charnov, 1976 ; MacArthur & Pianka, 1966 ; Stephens & Krebs, 1986 ), the mechanism underpinning the expression of behavioral variability remains the subject of active research debate (Biro & Stamps, 2010 ; Careau & Garland, 2012 ).…”

“…In turn, the metabolic rate as the measure of energy requirements, by setting a common currency of energy, can improve generalization in traits related to energy acquisition such as foraging decision and space use behavior (Shokri et al., 2024 ). Importantly, metabolic rate integrates a variety of typical trait proxies for energy acquisition and allocation in animals, for example, body mass, diet, mobility, and life history to yield a fine scale suite of continuous quantities (Brandl et al., 2022 ; Glazier, 2015 ).…”