Physiological Ecology of Insect Thermal Tolerance

The physiological ecology of insect thermal tolerance examines how temperature shapes the performance, survival and distribution of insects. As ectotherms, insects rely on external temperatures to regulate metabolic rate, locomotion, reproduction and development. Thermal performance curves characterise the relationship between body temperature and physiological traits, revealing optimal, suboptimal and lethal temperature thresholds. Plastic responses, such as acclimation and rapid hardening, allow many species to adjust tolerance limits over physiological timescales, while local adaptation drives population-level divergence in thermal sensitivity. Underlying mechanisms span molecular chaperones, membrane remodelling, ion and water balance, and hormonal pathways. These processes determine ecological outcomes, from range shifts under climate change to the persistence of pest and vector species. Understanding insect thermal ecology is critical for predicting responses to extreme events, guiding pest management, and conserving biodiversity in a warming world.

Research from Nature Portfolio

Recent experimental work has shown that exposure to simulated heatwaves can severely compromise male reproductive function in a flour beetle model, reducing sperm viability and causing transgenerational damage to offspring survival and lifespan. Such studies emphasise that heat tolerance is not limited to survival endpoints but extends to fertility and population persistence under climate extremes. Investigations into cold acclimation in the fruit fly Drosophila melanogaster have revealed extensive reorganisation of the transcriptome and metabolome when adults are maintained at low temperatures. Key metabolic pathways, including proline and glutathione metabolism, are upregulated alongside changes in membrane lipid composition, illustrating the depth of physiological remodelling that underpins chill tolerance. Comparative analyses across Drosophila species have further demonstrated that the capacity to maintain ion and water homeostasis at low temperature underlies interspecific variation in chill susceptibility. Species that preserve Malpighian tubule ion selectivity avoid lethal extracellular potassium accumulation, providing a physiological basis for differences in cold tolerance.

Physiological Ecology of Insect Thermal Tolerance publication trend

The graph below shows the total number of articles in physiological ecology of insect thermal tolerance across all publications each year (not limited to Nature Index journals).

Technical terms

Thermal performance curve: A graphical representation of physiological rate or fitness across a range of body temperatures.

Critical thermal maximum (CTmax): The highest temperature at which an insect can maintain locomotor function before entering a state of heat coma.

Chill coma: A reversible state of immobility induced by exposure to low temperatures.

Thermal Death Time: A measure of how long an organism can survive at a given stressful temperature.

Phenotypic plasticity: The capacity of a single genotype to produce different phenotypes in response to environmental variation.

Ion homeostasis: The regulation of intracellular and extracellular ion concentrations critical for nerve and muscle function under thermal stress.

References

1. Experimental heatwaves compromise sperm function and cause transgenerational damage in a model insect. Nature Communications (2018).
2. Cold acclimation wholly reorganizes the Drosophila melanogaster transcriptome and metabolome. Scientific Reports (2016).
3. The capacity to maintain ion and water homeostasis underlies interspecific variation in Drosophila cold tolerance. Scientific Reports (2015).
4. Phenotypic adaptation to temperature in the mosquito vector, Aedes aegypti. Global Change Biology (2023).
5. Thermal limits of survival and reproduction depend on stress duration: A case study of Drosophila suzukii. Ecology Letters (2024).