DOI: 10.5061/dryad.8gtht770p
title: Predator-mediated resource limitation shapes body and head size variation in stickleback populations

description: Predator and prey communities are key drivers of phenotypic variation in
 consumers, yet the ecological interactions shaping these traits remain
 understudied in natural food webs. This dataset supports a comparative
 study examining how phenotypic variation in 34 Greenlandic threespine
 stickleback (Gasterosteus aculeatus) populations is influenced by the
 presence of an intraguild predator, Arctic char (Salvelinus alpinus). The
 dataset includes morphological measurements of stickleback body and head
 size, zooplankton community composition, and biomass estimates. Our
 findings indicate that in the presence of Arctic char, stickleback exhibit
 larger body sizes with relatively smaller heads, consistent with
 resource-mediated ontogenetic shifts observed in other fishes. Path
 analysis suggests that predator-mediated changes in zooplankton
 communities partially explain this shift, highlighting indirect effects of
 top predators on consumer resource limitation and allometric trait
 variation. This dataset provides valuable insights into the ecological
 mechanisms underlying phenotypic diversity and can be leveraged for
 further studies on trophic interactions, trait allometry, and evolutionary
 ecology.
description: # Predator-mediated resource limitation shapes body and head size
 variation in stickleback populations Dataset DOI:
 [10.5061/dryad.8gtht770p](10.5061/dryad.8gtht770p) # ## Dataset
 Description This dataset accompanies the study investigating how the
 presence of an intraguild predator (Arctic char, *Salvelinus alpinus*)
 influences phenotypic variation in Greenlandic threespine stickleback
 (*Gasterosteus aculeatus*). Specifically, it includes morphological
 measurements of stickleback populations, zooplankton community
 composition, and biomass estimates, as well as measures of Lake
 morphometry. Additionally it containes the photos taken of the stickleback
 specimen for morphological measurements. The dataset can be used to
 explore trophic interactions, consumer trait allometry, and
 predator-induced selection pressures. ### Files and variables #### File:
 Fish\_data.csv **Description:** Fish population identity and morphological
 variables:  For a description of the morphological measurements see Figure
 S2 and Table S2 in the supplementary material. All measurements are in
 millimeter  ##### Variables * LakeID: Unique identifier for each lake/fish
 population * FishID: Unique identifier for each fish * SL: Standard length
 of the fish * Epax_height_closed: Epaxial muscle height when mouth is
 closed * Coupler: Coupler link (see Table S2) * Fixed: Fixed link  *
 Input: Input link  * Output: Output link * Gape: Gape width  *
 Buccal_length: Length of the Buccal cavity * Neuro_Outlever: neurocranium
 outlever  * Jaw_Outlever: Outlever of the lower jaw * Jaw_Inlever: Inlever
 of the lower jaw  * Jaw_prot: Jaw protrusion * EpaxWidth: Expaxial width *
 Eye: Eye diameter  * Epax_height_open: Epaxial muscle height when mouth is
 open * Head_length: Length of the head #### File: Lake\_data.csv
 **Description:** Data on the lake identity and condition, including the
 fish and zooplankton community ##### Variables * LakeID: Unique identifier
 for each lake/fish population * Lat: Latitude * Long: Longitude * Fish:
 Fish community composition: SB = stickleback only, SBC = stickleback and
 char * Areaha: Lake surface area in ha * TotalBM: Total Biomass of all
 zooplankton (µg/L) * CalanoidBM: Biomass of calanoid copepods (µg/L) *
 Non_evasiveBM: Biomass of non-evasive zooplankton taxa (µg/L) * CPUE:
 Stickleback catch per unit effort (per h) * ab_Chydoridae: Abundance of
 Chydoridae (ind./L) * ab_Calanoida: Abundance of Calanoida *
 ab_Daphniidae: Abundance of Daphniidae * ab_Cyclopoida: Abundance of
 Cyclopoida * ab_Polyphemus: Abundance of Polyphemus *
 ab_Macrothrix: Abundance of Macrothrix * ab_Holopedium: Abundance of
 Holopedium * ab_Bosmina: Abundance of Bosmina ## Photographs ####
 File: Fish\_photos\_moosmann\_et\_al\_2025 This files contains the
 photographs of stained threespine stickleback used for morphological
 analysis. The image files are organized by lake, the folder names
 correspond with the LakeIDs in the csv files. Each fish was fotographed
 from three perspectives: dorsally, laterally with mouth open and laterally
 with mouth closed. The individual images are labeled by Lake ID,
 perspective, and an unique ID number that corresponds with FishID in the
 file Fish_data.csv. # ## Code/software #### File: JEB\_2024\_00346.R
 **Description:** R file containing all the analysis steps performed in the
 Manuscript This dataset can be viewed and analyzed using free, open-source
 software. The primary software used for data processing and analysis was R
 (version R version 4.4.1). The following R packages were loaded for data
 cleaning, visualization, and statistical modeling: readr – for reading CSV
 files tidyr – for data wrangling dplyr – for data manipulation ggplot2 –
 for data visualization lme4 – for mixed-effects modeling lmerTest – for
 statistical inference on mixed models vegan – for ecological multivariate
 analyses ggeffects – for extracting model predictions rstan – for Bayesian
 statistical modeling brms – for Bayesian regression modeling To ensure
 reproducibility, the following workflow was used: Data were imported and
 cleaned using readr and dplyr. Morphological and zooplankton data were
 reshaped using tidyr. Exploratory data visualization was performed with
 ggplot2. Statistical modeling, including path analysis and mixed models,
 was conducted using lme4, lmerTest, vegan, and Bayesian models using rstan
 and brms. Model predictions and visualizations were generated with
 ggeffects.