Repeated experimental challenges do not shorten adult telomeres in a songbird

Responding to environmental challenges can have both positive and negative effects on fitness, but the mechanisms and/or biomarkers underlying these links are not well understood. Telomeres, repetitive sections of DNA that form protective caps at chromosome ends, which enhance genome integrity and often predict organismal lifespan, may be important in this context. Some evidence suggests that stress exposure shortens telomeres, but most studies are correlational and/or conducted during early life; thus, how stress exposure influences telomeres in adulthood is not well known. Here we experimentally exposed wild-captured adult house sparrows (Passer domesticus) to a series of standardized protocols of repeated, rotating stressors (including threats, unpredictable food availability, and immune challenges) designed to increase stress levels. Although there were some effects of the treatment on glucocorticoid levels and mass dynamics, there were no effects on telomeres during any of the 6-11..., We completed 4 experiments in sequence, which reflected a combination of three agendas. First, space limited sample size for any one experiment, so replicates were needed. The first experiment was conducted inside, whereas the 2nd-4th were conducted in outdoor aviaries in small flocks, which for house sparrows is a more natural context than indoors, and so we thought our treatments would better reflect natural, albeit elevated challenges. Finally, we were also interested in assessing the potential for different types of stressors to have different effects; hence, we varied the potential threats within the first 3 experiments and shifted to different types of stressors in the last experiment (below).
Captive housing conditions
The first experiment was conducted in an indoor aviary using local male house sparrows captured from Fargo, North Dakota, and three others were done in an outdoor aviary facility using local house sparrows of both sexes captured from Lexington, KY. In North Dakota,..., # Data from: Repeated experimental challenges do not shorten adult telomeres in a songbird

Dataset DOI: [10.5061/dryad.3ffbg79xn](10.5061/dryad.3ffbg79xn)

## Description of the data and file structure

This document provides metadata for the data files used in the MS entitled “Repeated experimental challenges do not shorten adult telomeres in a songbird”. Two files (.csv format) are described.

### Files and variables

#### File: Alldata.csv

**Description:** This file contains data from 4 experiments, details of which are in the methods section. Empty (blank) cells indicate missing data, the reasons for this depend on the variable and are described in brackets for each.

##### Variables

* BirdID: Unique code for each subject
* Experiment: A label for each of the four experiments
* Treatment: A label for which treatment each subject received. Options are:

Control – Left alone as much as possible

Threat stress – Received the rotating stressors

Immune – Received repeated injec...,