ABSTRACT
High temperatures and heatwaves are rapidly emerging as an important threat to many aspects of physiology and behavior in females during lactation. The body's capacity to dissipate heat is reduced by high ambient temperatures, increasing the risk of hyperthermia. Exposure to wind, a pervasive environmental factor for most terrestrial animals, is known to increase heat loss, but its effects on the reproductive performance of small mammals remains unclear. In the present study, the effects of wind on the energy budgets, resting metabolic rate and milk energy output (MEO) were measured in lactating Swiss mice at 21 and 32.5°C. Females kept at 32.5°C had a significantly lower resting metabolic rate, food intake and MEO, and lighter offspring, than those kept at 21°C. However, exposure to wind increased the asymptotic food intake of females kept at 32.5°C by 22.5% (P<0.01), their MEO by 20.7% (P<0.05) and their litter mass by 17.6% (P<0.05). The body temperature of females kept at 32.5°C was significantly higher during lactation than that of females kept at 21°C, but this difference was reduced by exposure to wind. These findings suggest that exposure to wind considerably improves reproductive performance, increasing the fitness of small mammals while undergoing hot temperatures during heatwaves.
Footnotes
Competing interests
All authors declare no conflicts of interest and have approved the final version of the manuscript.
Author contributions
Methodology: G.-M.D., J.-X.Y., J.-Q.X., Y.-F.B., Q.C., Z.-J.Z.; Formal analysis: G.-M.D., J.C., Z.-J.Z.; Investigation: G.-M.D., J.-Q.X., Q.C., Z.-J.Z.; Data curation: J.-X.Y., Y.-F.B., J.C., Z.-J.Z.; Writing - original draft: G.-M.D., Z.-J.Z.; Writing - review & editing: Z.-J.Z.; Supervision: Z.-J.Z.
Funding
This study was supported by grants from the National Natural Science Foundation of China (31670417, 31870388) and partly supported by Research Grants for Students (KZS1910049, 2018kx181, 2019kx171) and the Graduate Scientific Research Foundation of Wenzhou University (3162018037, 615819123).
Supplementary information
Supplementary information available online at https://jeb.biologists.org/lookup/doi/10.1242/jeb.231415.supplemental
- Received June 16, 2020.
- Accepted July 7, 2020.
- © 2020. Published by The Company of Biologists Ltd
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