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Long-term research and hierarchical models reveal consistent fitness costs of being the last egg in a clutch

Citation

Acevedo, Cheyenne et al. (2020), Long-term research and hierarchical models reveal consistent fitness costs of being the last egg in a clutch, Dryad, Dataset, https://doi.org/10.5061/dryad.fttdz08pp

Abstract

1. Maintenance of phenotypic heterogeneity in the face of strong selection is an important component of evolutionary ecology, as are the consequences of such heterogeneity. Organisms may experience diminishing returns of increased reproductive allocation as clutch or litter size increases, affecting current and residual reproductive success. Given existing uncertainty regarding trade-offs between the quantity and quality of offspring, we sought to examine the potential for diminishing returns on increased reproductive allocation in a long-lived species of goose, with a particular emphasis on the effect of position in the laying sequence on offspring quality. 2. To better understand the effects of maternal allocation on offspring survival and growth, we estimated the effects of egg size, timing of breeding, inter- and intra-annual variation, and position in the laying sequence on gosling survival and growth rates of black brent (Branta bernicla nigricans) breeding in western Alaska from 1987–2007. 3. We found that gosling growth rates and survival decreased with position in the laying sequence, regardless of clutch size. Mean egg volume of the clutch a gosling originated from had a positive effect on gosling survival (β = 0.095, 95% CRI: 0.024, 0.165), and gosling growth rates (β = 0.626, 95% CRI: 0.469, 0.738). Gosling survival (β = -0.146, 95% CRI: -0.214, -0.079) and growth rates (β = -1.286, 95% CRI: -1.435, -1.132) were negatively related to hatching date. 4. These findings indicate substantial heterogeneity in offspring quality associated with their position in the laying sequence. They also potentially suggest a trade-off mechanism for females whose total reproductive investment is governed by pre-breeding state. 20-Mar-2020

Methods

See the manuscript in the attached files. 

Usage Notes

mass_input.csv

This data file is the input file for the growth analysis. 

mean_clutch_vols.csv

Data for the mean egg volume of each brood.

survival_input.csv

This data file is the input file for the survival analysis. 

growth_model.R

This R script analyses the gosling growth data. 

phi_model.R

This R script analyses the gosling survival data.

Funding

Alaska Science Center

U.S. Geological Survey, Award: DEB 9815383

Migratory Bird Management Region 7, US Fish and Wildlife Service

Ducks Unlimited

The Morro Bay Brant Group

Phil Jebbia (in memory of Marnie Shepherd)

National Science Foundation, Award: DEB 9815383

National Science Foundation, Award: OPP 9214971

National Science Foundation, Award: OPP 9985931

National Science Foundation, Award: OPP 0196406

National Science Foundation, Award: DEB 0743152

National Science Foundation, Award: DEB 1252656

Alaska Science Center

Migratory Bird Management Region 7, US Fish and Wildlife Service

Ducks Unlimited

The Morro Bay Brant Group

Phil Jebbia (in memory of Marnie Shepherd)