Plastic Responses to Interacting Environmental Drivers

Abstract

Natural environments fluctuate at different time scales, and animals have to integrate information from various cues to maintain performance across environmental gradients. Mismatches between environmental signals, which are enhanced by global warming, could alter thermal plasticity of physiology and behaviour. We showed that transgenerational effects can interact with reversible thermal acclimation to alleviate the performance cost of a mismatch between ancestral and offspring environments. Exposure to mismatched photoperiod and temperature cues altered thermal acclimation of whole-animal performance, and this effect was at least partly mediated by thyroid hormone. The interaction between ancestral and acclimation thermal environments, and the combined effect of seasonal cues modified group behaviour and dispersal. Temperature and food availability affected mitochondrial efficiency, thereby modifying the link between whole-animal oxygen consumption, energy production and behaviour. Our results indicate that a mismatch in seasonal cues, rather than an increase in temperature only, could be a signal for changes in physiology, behaviour and other phenological events observed in response to global warming. Furthermore, plasticity at different time-scales can increase animal resilience to such environmental mismatches. We showed that whole-animal oxygen consumption does not predict energy production or use, and needs to be calibrated with mitochondrial efficiency to assess ATP production under different environmental conditions. This dissociation between oxygen consumption and energy production can partially explain the variation in the link between oxygen consumption and behaviour observed across environmental contexts.