Thermal Acclimation Ability Varies in Temperate and Tropical Aquatic Insects from Different Elevations

Area of Science:

• Ecology
• Evolutionary Biology
• Climate Change Biology

Background:

• Organisms exhibit varying thermal tolerance based on environment.
• Acclimation ability, or plastic adjustments to thermal sensitivity, is less understood.
• Environmental thermal variability may drive the evolution of acclimation ability.

Purpose of the Study:

• To test hypotheses on the evolution of acclimation ability in relation to environmental thermal regimes.
• To investigate potential trade-offs between heat tolerance and acclimation capacity.
• To assess the vulnerability of tropical aquatic insects to climate warming.

Main Methods:

• Measured critical thermal maximum (CTMAX) acclimation in temperate and tropical mayflies and stoneflies.
• Compared acclimation ability across different latitudes and elevations in mountain streams.
• Analyzed relationships between stream temperature, thermal tolerance, and acclimation capacity.

Main Results:

• Tropical mayflies had lower acclimation ability than temperate mayflies.
• Acclimation ability in mayflies correlated with stream temperature variability.
• Stoneflies showed similar acclimation responses across latitudes; no heat tolerance-acclimation trade-off was observed.

Conclusions:

• Lower elevation tropical aquatic insects are more susceptible to climate warming due to reduced acclimation.
• Environmental thermal variability influences the evolution of acclimation in mayflies.
• Stonefly acclimation may be influenced by factors like temperate origins or foraging behavior.