Data from: Interplay of cooperative breeding and predation risk on egg allocation and reproductive output
Data files
Feb 28, 2024 version files 50.85 KB
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cs_dat2.txt
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dat_yolkmass_cort2.txt
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emass_dat2.txt
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fledged_dat2.txt
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hatched_dat.txt
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incubation_dat2.txt
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README.md
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XENOCANTO_Ref_GABAR_GOSHAWK_CALLS.txt
Abstract
Predation risk can influence behaviour, reproductive investment and, ultimately, individuals’ fitness. In high-risk environments, females often reduce allocation to reproduction, which can affect offspring phenotype and breeding success. In cooperative breeders, helpers contribute to feed the offspring, and groups often live and forage together. Helpers can therefore improve reproductive success, but also influence breeders’ condition, stress levels and predation risk. Yet, whether helper presence can buffer the effects of predation risk on maternal reproductive allocation remains unstudied. Here, we used the cooperatively breeding sociable weaver Philetairus socius to test interactive effects of predation risk and breeding group size on maternal allocation to clutch size, egg mass, yolk mass, and yolk corticosterone. We increased perceived predation risk before egg laying using playbacks of the adults’ main predator, gabar goshawk (Micronisus gabar). We also tested interactive effects of group size and prenatal predator-playbacks on offspring hatching and fledging probability. Predator-exposed females laid eggs with 4% lighter yolks, but predator-calls’ exposure did not clearly affect clutch size, egg mass or egg corticosterone levels. Playback-treatment effects on yolk mass were independent of group size, suggesting that helpers’ presence did not mitigate predation risk effects on maternal allocation. Although predator-induced reductions in yolk mass may decrease nutrients’ availability to offspring, potentially affecting their survival, playback-treatment effects on hatching and fledging success were not evident. The interplay between helper presence and predator effects on maternal reproductive investment is still an overlooked area of life history and physiological evolutionary trade-offs that requires further studies.
README: Data from: Interplay of cooperative breeding and predation risk on egg allocation and reproductive output
https://doi.org/10.5061/dryad.rjdfn2zkk
These datasets contain results of an experiment aimed at increasing perceived predator presence, by playing back calls of a predator of adults, to test how this affects maternal allocation — clutch size, egg mass, yolk mass and yolk corticosterone — and reproductive output — hatching and fledging success. The study was conducted on the colonial cooperatively breeding sociable weaver (Philetairus socius), with the aim of assessing how breeding group sizes may modulate maternal allocation responses to predation risk.
This repository includes six datasets (see below), one R script that runs all analyses and produces figures included in the manuscript, called "open_code_models.R"; one file citing file sources and credits for calls used to build the playback tracks called "XENOCANTO_Ref_GABAR_GOSHAWK_CALLS"; one README file.
Description of the data and file structure
Please read Methods in the manuscript for details on how data was collected and processed.
"cs_dat2.txt" - used to test effects on clutch size; includes the following columns, by order of appearance: col_nest_code (nest identity); NestCode (clutch identity); colony (colony identity); clutch_size (nr of eggs laid); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers)
"emass_dat2.txt" - used to test effects on egg mass; includes the following columns, by order of appearance: col_nest_code (nest identity); NestCode (clutch identity); colony (colony identity); mass_egg (egg mass in grams); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers); clutch_size (nr of eggs laid)
"dat_yolkmass_cort2.txt" - used to test effects on yolk mass and corticosterone concentration; includes the following columns, by order of appearance: Sample_ID (yolk sample identity); corticosterone_pg_mg (concentratio of yolk corticosterone in pg/mg); mass_yolk_mg (yolk mass in mg); col_nest_code (nest identity); NestCode (clutch identity); colony (colony identity); mass_egg (egg mass in grams); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers)
"hatched_dat.txt" - used to test effects on hatching success; includes the following columns, by order of appearance: col_nest_code (nest identity); NestCode (clutch identity); colony (colony identity); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers); hatched (0 for no, 1 for yes: at the egg level); clutch_size (nr of eggs laid)
"fledged_dat.txt" - used to test effects on fledging success from hatching; includes the following columns, by order of appearance: col_nest_code (nest identity); NestCode (clutch identity); colony (colony identity); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers); fledged(0 for no, 1 for yes: at the chick level); clutch_size (nr of eggs laid); hatched (0 for no, 1 for yes --- only hatched chicks included here)
"incubation_dat2.txt" - used to test effects on Nest visit rate during incubation; includes the following columns, by order of appearance: NestCode (clutch identity); NestCode_dchicks (day of recording for each clutch ID); Total_visits (nr of visits to the nest): Total_time (total time nest was recorded); col_nest_code (nest identity); colony (colony identity); treatment (1 for predator, 0 for control); incubation_group_size (nr of birds visiting the nest - includes breeders and helpers); day_video (days_2_4 for videos recorded between days 2 and 4 of incubation: days_8_10 for videos recorded between days 8 and 10 of incubation); birdID (dummy identity for each bird visiting the nests).
Code/Software
R script to run all analyses and produce figures included in the manuscript: "open_code_models.R". To run the R script, please follow instructions in the R code. All analyses were conducted using the R software v.4.0.4 (R Core Team, 2022).
Methods
See Methods in "Interplay of cooperative breeding and predation risk on egg allocation and reproductive output"
Corresponding author: Rita Fortuna, ritafortuna@hotmail.com, rita.fortuna@ntnu.no