Developing organisms often plastically modify growth in response to environmental circumstances, which may be adaptive, but is expected to entail long-term costs. However, the mechanisms that mediate these growth adjustments and any associated costs are less well understood. In vertebrates, one mechanism that may be important in this context is the highly conserved signaling factor insulin-like growth factor-1 (IGF-1), which is often positively related to post-natal growth and negatively related to longevity. To test this idea, we exposed captive Franklin’s gulls (Leucophaeus pipixcan) to a physiologically relevant nutritional stressor by restricting food availability during post-natal development and examined the effects on growth, IGF-1, and two potential biomarkers of cellular and organismal aging (oxidative stress, and telomeres). During food restriction, experimental chicks gained body mass more slowly and had lower IGF-1 levels than controls. Following the food restriction, experimental chicks underwent compensatory growth, which was accompanied by an increase in IGF-1 levels. Interestingly however, there were no significant effects of the experimental treatment or of variation in IGF-1 levels on oxidative stress or telomeres. These findings suggest that IGF-1 is responsive to changes in resource availability but is not associated with increased markers of cellular aging during development in this relatively long-lived species.

This dataset contains multiple CSV files and the accompanying R script. The "primarydataset.csv" file includes feeding period, sampling period, absolute growth rates (g/day), IGF-1 concentrations (ng/mL), T/S ratios (note: this is a comparative metric- these values can only be compared to other T/S ratios that were run on the same plates), regression to the mean values (note: this value was calculated using a separate formula described in Verhulst 2013), principle component values (values calculated from wing chord (mm), head to bill length (mm), and culmen length (mm)), and daily body mass (in grams). This file also contains two measures associated with measuring oxidative stress including antioxidant capacity and protein carbonyl content.  Median absolute growth rates were calculated from the daily body mass values. Several supplementary datasets have also been included in this folder, including the "hatch.csv" dataset which contains chick hatch date, whether or not chicks hatched, time hatched, Chick ID, treatment, collection date (Early or Late), and hatch mass (g). The eggs for the early collection date were collected on May 7th, and the eggs for the late collection date were collected on May 25th. The "PCAdataset.csv" includes the structural growth data including wing chord (mm), head-to-bill length (mm), and culmen length (mm), values used for the PCA analysis.

R is needed to open the R script, all excel files have been uploaded as .csv.