Bees display limited acclimation capacity for heat tolerance.

Area of Science:

• Ecology
• Climate Change Biology
• Insect Physiology

Background:

• Bees are vital pollinators, facing threats from climate change.
• Understanding bee thermal tolerance is key to predicting their resilience.
• Limited research exists on bee responses to extreme temperatures.

Purpose of the Study:

• To measure critical thermal maximum (CTMax) acclimation in six bee species.
• To assess the influence of body size and CTMax on acclimation capacity.
• To determine if acute heat exposure enhances CTMax.

Main Methods:

• Measured CTMax response to short-term acclimation in six bee species.
• Calculated acclimation response ratio to assess capacity.
• Tested effects of body size, CTMax, and acute heat exposure.

Main Results:

• CTMax varied among species and increased with body size.
• Acclimation treatment did not significantly shift CTMax, except in one species.
• Acclimation capacity averaged 9% and was not linked to body size or CTMax.
• Acute heat exposure did not increase average CTMax.

Conclusions:

• Bees possess limited physiological capacity to enhance heat tolerance via acclimation.
• Insects generally exhibit weak plasticity in CTMax, emphasizing behavioral thermoregulation.
• Conservation of native vegetation is vital for providing thermal refuges for bees.