Heat-avoidance behavior associates with thermal sensitivity rather than tolerance in aphid assemblages.

Area of Science:

• Ecology
• Animal Behavior
• Climate Change Biology

Background:

• Predicting animal responses to increasing heat events due to climate warming is critical.
• Linking physiological thermal traits to heat-avoidance behavior is challenging due to limited research and data availability.

Purpose of the Study:

• To investigate the relationship between physiological thermal traits and heat-avoidance behavior in cereal aphid assemblages.
• To determine if heat tolerance (CTmax) or heat sensitivity (HS) better predicts the temperature at which aphids initiate heat-avoidance behavior (HAT).

Main Methods:

• Measured critical thermal maximum (CTmax) and heat-avoidance temperature (HAT) in cereal aphids under simulated linear temperature increases.
• Assessed heat sensitivity (HS) by calculating the declining rate of aphid survival time with increasing temperature.
• Examined correlations between CTmax and HAT, and between HS and HAT.

Main Results:

• A strong correlation was found between heat sensitivity (HS) and heat-avoidance temperature (HAT); more heat-sensitive aphids exhibited lower HAT.
• Critical thermal maximum (CTmax) showed a weak correlation with HAT.
• Heat sensitivity proved to be a more reliable indicator of heat-avoidance behavior than thermal tolerance.

Conclusions:

• Heat sensitivity is a key factor in predicting animal heat-avoidance behaviors under climate change.
• Future climate change impact assessments should incorporate thermal sensitivity alongside thermal tolerance for more accurate predictions of animal responses.