Experimental evidence that hyperthermia limits offspring provisioning in a temperate-breeding bird
Tapper, Simon (2020), Experimental evidence that hyperthermia limits offspring provisioning in a temperate-breeding bird, Dryad, Dataset, https://doi.org/10.5061/dryad.r2280gbb4
In many vertebrates, parental care can require long bouts of daily exercise, that can span several weeks. Exercise, especially in the heat, raises body temperature, and can lead to hyperthermia. Typical strategies for regulating body temperature during endurance exercise include modifying performance to avoid hyperthermia (anticipatory regulation hypothesis) and allowing body temperature to rise above normothermic levels for brief periods of time (facultative hyperthermia hypothesis). Facultative hyperthermia is commonly employed by desert birds to economize on water, but this strategy may also be important for chick-rearing birds to avoid reducing offspring provisioning when thermoregulatory demands are high. In this study, we tested how chick-rearing birds balance their own body temperature against the need to provision dependent offspring. We experimentally increased the heat dissipation capacity of breeding female tree swallows (Tachicyneta bicolor) by trimming their ventral feathers, and remotely monitored provisioning rates, body temperature, and the probability of hyperthermia. Birds with an experimentally increased capacity to dissipate heat (i.e., trimmed treatment) maintained higher feeding rates than controls at high ambient temperatures ( ≥ 25 ºC), while maintaining lower body temperatures. However, at the highest temperatures (≥25 ºC) trimmed individuals became hyperthermic. These results provide evidence that chick-rearing tree swallows use both anticipatory regulation and facultative hyperthermia during endurance performance. With rising global temperatures, individuals may need to increase their frequency of facultative hyperthermia to maintain nestling provisioning, and thereby maximize reproductive success.
The attached files contain the necessary descriptions for understanding and working with data used in the construction of Tapper et al. 2020 (Royal Society Open Science). The RSOS_dryad_readme.docx file contains descriptions of each file name attached to this data repository, and descriptions of the data contained within each column of a data file. Information pertaining to the R code, which has been provided in this data repository as a .Rmd (R Markdown) file, has not been provided within this readme file, because necessary descriptions for understanding our code are provided within the R code file itself.
Natural Sciences and Engineering Research Council of Canada, Award: RGPIN-04158-2014