Into the wild—a field study on the evolutionary and ecological importance of thermal plasticity in ectotherms across temperate and tropical regions

Abstract

Understanding how environmental factors affect the thermal tolerance of species is crucial for predicting the impact of thermal stress on species abundance and distribution. To date, species' responses to thermal stress are typically assessed on laboratory-reared individuals and using coarse, low-resolution, climate data that may not reflect microhabitat dynamics at a relevant scale. Here, we examine the daily temporal variation in heat tolerance in a range of species in their natural environments across temperate and tropical Australia. Individuals were collected in their habitats throughout the day and tested for heat tolerance immediately thereafter, while local microclimates were recorded at the collection sites. We found high levels of plasticity in heat tolerance across all the tested species. Both short- and long-term variability of temperature and humidity affected plastic adjustments of heat tolerance within and across days, but with species differences. Our results reveal that plastic changes in heat tolerance occur rapidly at a daily scale and that environmental factors on a relatively short timescale are important drivers of the observed variation in thermal tolerance. Ignoring such fine-scale physiological processes in distribution models might obscure conclusions about species' range shifts with global climate change. This article is part of the theme issue ‘Species’ ranges in the face of changing environments (part 1)’.

Rapid Adjustments in Thermal Tolerance and the Metabolome to Daily Environmental Changes – A Field Study on the Arctic Seed Bug Nysius groenlandicus

“…Based on these recordings, the mean temperature was calculated for the 1-h timespan prior to testing thermal tolerances. The mean temperature immediately prior to thermal assessment has been shown to be highly correlated with the heat tolerance in a range of insect species collected in the field ( Noer et al, 2022 ).…”

“…Evolutionary adaptation to changing and periodically stressful temperatures can be slow, and are sometimes constrained by genetic trade-offs or lack of adaptive genetic variation ( Araújo et al, 2013 ; Hoffmann et al, 2013 ). Conversely, rapid plastic adaptive changes can rescue individuals exposed to biotic and abiotic challenges at a shorter timescale, including daily environmental fluctuations ( Colinet and Hoffmann, 2012 ; Noer et al, 2022 ). Plastic changes might therefore be particularly relevant for arctic species exposed to unpredictable and rapid changes in the environment.…”

Introduction to the theme issue ‘Species' ranges in the face of changing environments’

“…In this issue, theory is extended to varying environmental conditions in a metapopulation [ 22 ], to the role of plasticity and the way it evolves in response to the nature of environmental variation [ 12 ], to the effect of drift, migration and demographic stochasticity on the risk of extinction in peripheral populations [ 14 ], and to the costs and benefits of dispersal in small populations [ 20 ]. Empirical studies also consider the role of plasticity at range margins [ 10 , 11 , 23 ]. Effects of dispersal may be influenced by the breeding system, which Dawson-Glass & Hargreaves [ 13 ] consider in relation to pollen limitation at range margins.…”

The role of phenotypic plasticity in the establishment of range margins

“…However, they do not account for phenotypic plasticity (hereafter referred to as plasticity), that is, the ability of a genotype to produce different phenotypes depending on the environment [12][13][14][15][16]. Plasticity may be an important mechanism for populations to buffer environmental changes, as shown both empirically [17][18][19][20][21][22][23] and theoretically [9,13,16,[24][25][26]. This is especially true when plasticity is adaptive (moving phenotypes towards the local optimum) [27,28].…”