Experimental demonstration of functional divergence in mitochondrial metabolism between two finch subspecies subjected to a thermal challenge

Different environments and climates can influence physiological variation and species’ geographic ranges. It has been suggested that mitochondria may play an essential role in this adaptation. We measured mitochondrial metabolism in two geographically separate subspecies of a songbird – the Long-tailed Finch, Poephila acuticauda - before and after ten days of heat exposure at 40°C. There were significant differences between subspecies, with the Red-billed P. a. hecki having lower proton leak and energy production efficiency than the Yellow-billed P. a. acuticauda, independent of treatment. Mitochondrial metabolism increased significantly after the heat treatment in five out of six variables in both subspecies, with P. a. hecki showing steeper reaction norms in metabolic acclimation to 40°C for the electron transport system. The heat treatment did not significantly increase circulating corticosterone, and at an individual level corticosterone and mitochondrial metabolism were unrelated. ..., The mitochondrial dataset was obtained using an O2k real-time respirometer (Oroboros Instruments). For details, see Materials and Methods., , # Experimental demonstration of functional divergence in mitochondrial metabolism between two finch subspecies subjected to a thermal challenge

Dataset DOI: [10.5061/dryad.0zpc86757](10.5061/dryad.0zpc86757)

## Description of the data and file structure

The data attached was collected for the manuscript titled \"Experimental demonstration of functional divergence in mitochondrial metabolism between two finch subspecies subjected to a thermal challenge\", and includes real-time respirometry measurements collected before and after a heat challenge, corticosterone levels measurements, genetic divergence estimation and climatological data of the area where these two finch subspecies (i.e., *Poephila acuticauda acuticauda* and *P. a. hecki*) spread in the wild.

### Files and variables

#### File: masterdb5.csv

**Description:** This dataset contains 150 observations for the two subspecies of finches (i.e. the Yellow-billed *Poephila acuticauda acuticauda* and the Red-billed *P. a. hecki*)....,