Abstract
Performance benefits of stable, warm muscles are believed to be important for the evolution of endothermy in mammals, birds and flying insects. However, thermal performance curves have never been measured for a free-flying endotherm, as it is challenging to vary body temperatures of these animals, and maximal flight performance is difficult to elicit. We varied air temperatures and gas densities to manipulate thoracic temperatures of flying honeybees from 29°C to 44°C, with low air densities used to increase flight metabolic rates to maximal values. Honeybees showed a clear thermal performance curve with an optimal temperature of 39°C. Maximal flight metabolic rates increased by approximately 2% per 1°C increase in thoracic temperature at suboptimal thoracic temperatures, but decreased approximately 5% per 1°C increase as the bees continued to heat up. This study provides the first quantification of the maximal metabolic performance benefit of thermoregulation in an endotherm. These data directly support aerobic capacity models for benefits of thermoregulation in honeybees, and suggest that improved aerobic capacity probably contributes to the multiple origins of endothermic heterothermy in bees and other insects.
Original language | English (US) |
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Article number | 20220298 |
Journal | Proceedings of the Royal Society B: Biological Sciences |
Volume | 289 |
Issue number | 1981 |
DOIs | |
State | Published - Aug 31 2022 |
Keywords
- endothermy
- honeybees
- maximal flight metabolism
- thermal performance
- thermoregulatory benefits
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- General Immunology and Microbiology
- General Environmental Science
- General Agricultural and Biological Sciences