Behavioural effects of temperature on ectothermic animals: unifying thermal physiology and behavioural plasticity

Abstract

Temperature imposes significant constraints on ectothermic animals, and these organisms have evolved numerous adaptations to respond to these constraints. While the impacts of temperature on the physiology of ectotherms have been extensively studied, there are currently no frameworks available that outline the multiple and often simultaneous pathways by which temperature can affect behaviour. Drawing from the literature on insects, we propose a unified framework that should apply to all ectothermic animals, generalizing temperature's behavioural effects into: (1) kinetic effects, resulting from temperature's bottom-up constraining influence on metabolism and neurophysiology over a range of timescales (from short to long term), and (2) integrated effects, where the top-down integration of thermal information intentionally initiates or modifies a behaviour (behavioural thermoregulation, thermal orientation, thermosensory behavioural adjustments). We discuss the difficulty in distinguishing adaptive behavioural changes from constraints when observing animals' behavioural responses to temperature. We then propose two complementary approaches to distinguish adaptations from constraints, and categorize behaviours according to our framework: (i) 'kinetic null modelling' of temperature's effects on behaviour; and (ii) behavioural ecology experiments using temperature-insensitive mutants. Our framework should help to guide future research on the complex relationship between temperature and behaviour in ectothermic animals.

Some like it hot: from individual to population responses of an arboreal arid‐zone gecko to local and distant climate

“…Hence, in 2016 individuals likely had less food to digest and, at the same time, more optimal temperatures for digestion, which should make the necessity of basking outside the tree unnecessary (Abram et al 2016). In addition, we assume that necessary movements in cool days for diurnal thermoregulation could have decreased body condition in comparison to hot days for which no thermoregulation and thus, no movements were necessary for digestion (Angilletta 2009, Abram et al 2016. Basking might also increase predator exposure and overheating risk and thus reduce survival (Angilletta 2009).…”

Diurnal foraging of a wild coral‐reef fish Parapercis australis in relation to late‐summer temperatures

“…By contrast, siteattached species may be less capable of re-locating and hence, more inclined to cope by minimizing aerobically-costly behaviours (i.e. exhibit behavioural plasticity; Abram et al, 2017;Johansen et al, 2014) during ecological processes. This idea is supported by preliminary field (Scott et al, 2017) and laboratory (Nowicki et al, 2012) findings.…”

How climate change affects the seasonal ecology of insect parasitoids

“…Future research will have to assess the relative importance and potential of these mechanisms in mediating the responses of parasitoid species to climatic change (Bradshaw & Holzapfel, 2006;Merilä & Hendry, 2014;Duputié et al, 2015;Abram et al, 2016). This could be achieved by experimental evolution frameworks, community-scale experiments, and by exploring datasets on long-term host-parasitoid interactions.…”

“…Temperature is the primary abiotic factor affecting insect development, reproduction, foraging behaviour, distribution range, and the timing of their activities (Angilletta, 2009;Abram et al, 2016;Sánchez-Guillén et al, 2016;Córdoba-Aguilar et al, 2018). In temperate and polar regions, insects have evolved different strategies to survive recurring environmental conditions that are unsuitable for growth and reproduction.…”