Data from: Are bigger eggs better? Positive genetic and environmental correlations between egg size and hatching success in a precocial bird
Data files
Oct 08, 2026 version files 216.51 KB
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dataset.txt
101.24 KB
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pedigree.txt
112.78 KB
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README.md
2.49 KB
Abstract
Egg size represents a primary form of parental investment, but whether it is causally related to offspring fitness is difficult to establish. We mated Japanese quail (Coturnix japonica) from replicated selection lines for high and low maternal investment in egg size to partners from the same and alternate selection line. We combined this with detailed pedigree information to partition variation in the size and hatching success of their eggs into their underlying genetic and non-genetic components, and estimated the correlation between these traits at all levels. Variation in egg size was primarily explained by additive genetic variation among mothers (h2 = 65 %) and variation in hatching success also had an additive genetic component among mothers (h2 = 16 %), with little evidence for additive effects of the father on both traits. Importantly, the correlations between egg size and hatching success were positive and similar at the genetic level among mothers and the non-genetic level within mothers. Furthermore, in one of the two replicates the eggs from females selected for high maternal investment in egg size had higher hatching success. We interpret these results as being most parsimoniously explained by a positive causal effect of egg size on hatching success.
Dataset DOI: 10.5061/dryad.tqjq2bwfr
Description of the data and file structure
This repository contains the data used for a project on quantitative genetics of the correlation between egg size and hatching success, using data from a population of captive Japanese quail. Specifically, the repository contains files used in the following study:
Vedder O, Postma E, Tschirren B, Moiron M (2026) Are bigger eggs better? Positive genetic and environmental correlations between egg size and hatching success in a precocial bird. Evolution.
For any further information, please contact Oscar Vedder (oscar.vedder@ifv-vogelwarte.de) or Maria Moiron (mariamoironc@gmail.com).
Files and variables
File: dataset.txt
Description:
Variables
- year: year of the experiment (i.e., of measurement)
- mother_ID: individual mother unique identifier
- dam: individual mother unique identifier
- mother_line: category variable with two levels: ‘high’ and ‘low’, representing the two different maternal selection lines
- mother_replicate: categorical variable with two levels: 1 and 2, representing the two line replicates used in the experiment
- father_ID: individual father unique identifier
- father_line: category variable with two levels: ‘high’ and ‘low’, representing the two different paternal selection lines
- egg_mass: egg mass measured in grams
- F_egg: inbreeding coefficient of each individual egg
- HS: hatching success, measured as a binary variable with two levels: 0 = unsuccessful hatching and 1 = successful hatching
- storage_days: number of days eggs were stored at 12 °C before artificial incubation. Eggs were placed in storage within one day of laying and artificially incubated in batches within 12 days of laying, resulting in storage times ranging from 0 to 12 days (mean = 4.3 days)
File: pedigree.txt
Description:
Variables
- id: unique individual
- sire: father of the individual (NA = not available)
- dam: mother of the individual (NA = not available)
Code/software
The data can be viewed with any free text editor software. All models were fitted within a Bayesian framework using the R package MCMCglmm (Hadfield 2010).