DOI: 10.5061/dryad.rr4xgxdmw
title: Defensive colouration is not a reliable indicator of fungal infection in aposematic poison frogs

description: Color signals can be altered by pathogenic infections through different
 pathways, potentially compromising their signaling functions. This
 association has been widely examined in the context of sexual selection,
 whereas little is known about its effects on aposematic coloration. We
 measured dorsal skin color traits of the aposematic poison frog
 Dendrobates tinctorius using multispectral digital imaging. For each
 individual, we also quantified Batrachochytrium dendrobatidis (Bd)
 infection status and load using droplet digital PCR (ddPCR). We compared
 the brightness, saturation and hue from melanin- and carotenoid-based
 coloration between frogs, using linear or bayesian circular regressions
 models, and found no association between Bd infection status or
 load and differences in coloration. Instead, body size influenced both
 infection outcomes and colouration, with sex-specific patterns suggesting
 potential ontogenetic or life-history trade-offs. Our findings
 highlight that the links between colour expression and condition are more
 context- and taxa-dependent than often assumed, and suggest that, in D.
 tinctorius, defensive signals may remain stable despite pathogen exposure.
 This dataset provides a detailed resource to explore the relationships
 between pathogen infection, host traits, and color expression in an
 aposematic species.
description: # Defensive colouration is not a reliable indicator of fungal infection in
 aposematic poison frogs Date of last update: 2025-08-01 #### Repository
 contents Bd_colouration_project/ ├── data/ │    └──
 Bd_coloration_metadata.csv -&gt; Final dataset used for statistical
 analysis \| analyses, including frog and Bd infection information. │   
 └── Black_RGB_KC.csv -&gt; RGB reflectance values (mean and sd) of the
 black ROIs \| for Kaw and Cacao populations. │ └── Black_RGB_M.csv -&gt;
 RGB reflectance values (mean and sd) of the black ROIs for \| Mataroni
 population. │ └── Black_RGB_N.csv -&gt; RGB reflectance values (mean and
 sd) of the black ROIs for \| Nouragues population. │ └── Black_RGB_PF.csv
 -&gt; RGB reflectance values (mean and sd) of the black ROIs for \| Petit
 Matoury and Mont Fortuné populations. │ └── Yellow_RGB_KC.csv -&gt; RGB
 reflectance values (mean and sd) of the yellow ROIs \| for Kaw and Cacao
 populations. │ └── Yellow_RGB_M.csv -&gt; RGB reflectance values (mean and
 sd) of the yellow ROIs \| for Mataroni population. │ └── Yellow_RGB_N.csv
 -&gt; RGB reflectance values (mean and sd) of the yellow ROIs \| for
 Nouragues population. │ └── Yellow_RGB_PF.csv -&gt; RGB reflectance values
 (mean and sd) of the yellow ROIs \| for Kaw and Cacao populations. ├──
 scripts/ └── Effects_Bd_coloration.R -&gt; R script to reproduce analyses
 #### Description of "Bd_coloration_metadata.csv" This CSV file
 contains the information regarding the Dendrobates tinctorius individuals
 sampled in 2023, their measurements, and the ddPCR results (Bd infection
 status and infection loads). * Site: Name of the population * Sample_ID:
 Unique ID for each D. tinctorius individual sampled * Target: Specific DNA
 sequence being amplified and detected (pathogen Bd) * Supermix: Premixed
 reaction buffer used in ddPCR containing all necessary reagents (excluding
 dUTP) for probe-based amplification * DyeName: Fluorescent dye linked to a
 probe, identifying which target is measured (FAM for Bd) *
 Concentration_1/2/3: Number of target DNA copies per microliter of
 reaction, based on * the proportion of positive to total droplets for each
 ddPCR run * Accepted_1/2/3: Total number of droplets successfully
 generated and analyzed from * a sample that passed quality control
 thresholds for each ddPCR run * Positive_1/2/3: Number of droplets
 containing detectable levels of the target DNA * (showing a fluorescence
 signal above threshold) for each ddPCR run * Negative_1/2/3: Number of
 droplets that do not contain the target DNA and show no * detectable
 fluorescence for each ddPCR run * freq:Number of times that a ddPCR was
 run for each sample * Infected:Outcome of ddPCR regarding Bd infection
 (final decision) * Bd.load_co: Number of Bd DNA copies detected per μl of
 each swab sample * Sex: Sex of the individual (Female, Male, or Juvenile)
 * Weight: Weight of the frog (in grams) * SVL: Snout-vent length of the
 frog (in cm) Note: any NA cells represent not applicable data (e.g., NA
 for juveniles' sex). #### Description of
 "Effects_Bd_coloration.R" R code for reproducing the analyses
 and visualizations presented in the article, including statistical tests
 and figure generation. ###### **Software version:** R version 4.4.2
 (2024-10-31 ucrt) Platform: x86_64-w64-mingw32 (64-bit) Running under:
 Windows 11 ###### **Packages&version:** **Data maniuplation and
 organization** library(tidyverse) # 2.0.0 library(dplyr) #1.1.4
 library(stringr) # 1.5.2 library(purrr) # 1.1.0 library(magrittr) # 2.0.4
 library(here) # 1.0.2 **Visualization** library(ggplot2) # 4.0.0
 library(ggpubr) # 0.6.1 library(ggrepel) # 0.9.6 library(colorspace) #
 2.1-1 **Statistical modeling and inference** library(MuMIn) # 1.48.11
 library(car) # 3.1-3 library(effects) # 4.2-4 library(Matrix) # 1.7-1
 library(lme4) # 1.1-37 library(lmerTest) # 3.1-3 library(DHARMa) # 0.4.7
 library(MASS) # 7.3-65 library(ggeffects) # 2.3.1 library(emmeans) #
 1.11.2-8 library(smatr) # 3.4-8 **Circular data analysis (Hue analysis)**
 library(bpnreg) # 2.0.3 library(circular) # 0.5-2 library(signal) # 1.8-1