Meta-analysis reveals weak but pervasive plasticity in insect thermal limits

Area of Science:

• Environmental Science
• Zoology
• Climate Change Biology

Background:

• Climate change is increasing extreme temperature events globally.
• These events pose significant threats to insect populations, including pollinators, pests, and disease vectors.
• Insect survival during thermal extremes may depend on their ability to acclimate.

Purpose of the Study:

• To quantify the extent of thermal limit plasticity in insects.
• To assess the effectiveness of this plasticity in aiding insect survival during extreme temperatures.
• To identify factors influencing thermal plasticity across insect species and life stages.

Main Methods:

• Conducted a meta-analysis of 74 studies, encompassing 1374 effect sizes and 102 insect species.
• Analyzed the relationship between acclimation temperature and critical thermal limits (maximum and minimum).
• Investigated potential publication bias and differences in plasticity between juvenile and adult insects.

Main Results:

• Thermal limit plasticity is widespread in insects but generally weak.
• A 1°C rise in acclimation temperature increased critical thermal maximum by 0.09°C; a 1°C decline decreased critical thermal minimum by 0.15°C.
• Juvenile insects exhibited greater plasticity than adults, and publication bias suggests plasticity may be overestimated.

Conclusions:

• Insect thermal limit plasticity offers limited adaptive benefits for surviving extreme climatic events.
• Physiological responses to temperature vary significantly through insect development (ontogeny).
• Further research is crucial, particularly in under-represented insect taxa and geographic regions, to fully understand adaptive capacity.