Designing a Seasonal Acclimation Study Presents Challenges and Opportunities

Abstract

Organisms living in seasonal environments often adjust physiological capacities and sensitivities in response to (or in anticipation of) environment shifts. Such physiological and morphological adjustments (“acclimation” and related terms) inspire opportunities to explore the mechanistic bases underlying these adjustments, to detect cues inducing adjustments, and to elucidate their ecological and evolutionary consequences. Seasonal adjustments (“seasonal acclimation”) can be detected either by measuring physiological capacities and sensitivities of organisms retrieved directly from nature (or outdoor enclosures) in different seasons or less directly by rearing and measuring organisms maintained in the laboratory under conditions that attempt to mimic or track natural ones. But mimicking natural conditions in the laboratory is challenging – doing so requires prior natural-history knowledge of ecologically relevant body temperature cycles, photoperiods, food rations, social environments, among other variables. We argue that traditional laboratory-based conditions usually fail to approximate natural seasonal conditions (temperature, photoperiod, food, ‘lockdown’). Consequently, whether the resulting acclimation shifts correctly approximate those in nature is uncertain, and sometimes is dubious. We argue that background natural history information provides opportunities to design acclimation protocols that are not only more ecologically relevant, but also serve as templates for testing the validity of traditional protocols. Finally, we suggest several best practices to help enhance ecological realism.

How seasonality influences the thermal biology of lizards with different thermoregulatory strategies: a meta‐analysis

“…summer; Foà & Bertolucci, 2001), but also because the same experimental protocol must be followed to produce comparable T pref data (Clusella‐Trullas & Chown, 2014); doing so can demand more time, effort, and resources than measuring T b . Despite the challenges that may accompany the design of seasonal studies (Huey & Buckley, 2022), garnering more information on seasonal changes in T pref is of utmost importance, as it will contribute to the goal of predicting species' potential for plasticity in the face of projected climatic change (Little & Seebacher, 2016).…”

Squamate metabolic rates decrease in winter beyond the effect of temperature

“…This, and other potential non‐controlled seasonal differences, weakens our ability to pinpoint the variables responsible for the observed patterns. However, we argue that for the purpose of describing natural trends, our measurements produce more ecologically relevant results, reflecting more accurately the changes occurring in nature, than if performed under fully controlled conditions (Huey & Buckley, 2022). The observations of this study can (and should) be validated in different taxa, biomes and methods, and in greater detail.…”

Comparative assessment of heat tolerance in weevils associated with a fire‐prone ecosystem

“…In order to reduce background thermal history effects (e.g., recent weather fronts; Terblanche & Hoffmann, 2020; Huey & Buckley, 2022), specimens were kept for two to four days after collection (Table 1) at room temperature (about 25°C) with foliage of their host as a food substrate. Species were identified taxonomically based on available literature and using the reference collections housed at Iziko Museum (Cape Town).…”