Microclimate buffering and thermal tolerance across elevations in a tropical butterfly

Area of Science:

• Ecology
• Climate Change Biology
• Zoology

Background:

• Microclimatic variability in tropical forests is crucial for species distribution and adaptation to environmental change, particularly for ectotherms.
• Existing climate datasets often lack forest interior data, limiting our understanding of tropical ectotherm thermal tolerance.

Purpose of the Study:

• To investigate microclimate variability experienced by *Heliconius* butterflies in the Andes.
• To assess the thermal tolerance of *Heliconius* butterflies across elevations.
• To determine the role of plasticity in thermal tolerance variation.

Main Methods:

• Monitored microclimate within tropical forests across the Andean range of *Heliconius* butterflies.
• Assessed the in-situ thermal tolerance of 10 *Heliconius* species.
• Conducted common-garden experiments with *H. erato* from different elevations to evaluate phenotypic plasticity.

Main Results:

• Tropical forests significantly buffer temperature and humidity, especially in lowland understories.
• Discrepancies were found between measured microclimate data and macroclimate databases (WorldClim2).
• High-elevation *Heliconius* populations exhibited lower heat tolerance, but plasticity reduced this difference in common-garden conditions.

Conclusions:

• Forest microclimate buffering is vital for species survival but is not well-represented in current climate datasets.
• Phenotypic plasticity in thermal tolerance may offer a buffer against global warming for some ectotherm species.
• Further research is needed to understand the long-term impacts of plasticity on tropical butterfly populations and species.