Data from: Inbreeding and competitor’s genetic relatedness affect dynamic male color-ornament expression in a cichlid fish
Data files
Jan 29, 2025 version files 7.64 KB
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Data_GussoneColour_dynamics_inbreedingR1.csv
5.26 KB
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README.md
2.38 KB
Abstract
We examined the dynamic color-expression in male groups of the cichlid Pelvicachromis taeniatus during competition over breeding sites. Groups (trios) were either inbred or outbred and consisted each of 2 unfamiliar brothers and an unfamiliar, unrelated male. Males of P. taeniatus are territorial and develop a carotenoid-based yellow coloration at the ventral body region and the caudal fin. Intense body coloration signals dominance. Our study showed i) that outbred males generally developed more intense yellow coloration (chromaticity) during the experiment compared to inbred males and ii) that related males were more intensively colored at the caudal fin after the trials than the unrelated males. In conclusion, our study indicates environment-dependent inbreeding depression in a male ornament as well as positive kin-selected effects on ornamentexpression. Our study describes understudied sources of phenotypic variation in ornamental traits in animals.
README: Inbreeding and competitor’s genetic relatedness affect dynamic male color-ornament expression in a cichlid fish
https://doi.org/10.5061/dryad.gtht76hx9
Description of the data and file structure
Files and variables
File: Data_GussoneColour_dynamics_inbreedingR1.csv
Variables
- Tank: Number of experimental tank
- Fish ID: Number to identify each fish: GroupID_tank number_related/nonrelated
- Family_tank_number: Identification number to determine the breeding line and breeding tank number
- Family: Breeding family identification number
- GroupID: Number of experimental trial to identify each trio
- Kin_Nonkin: Related or unrelated to other experimental fish in same tank/trial
- Inbreeding_Outbreeding: Inbred or outbred individual; I=Inbreeding, O=Outbreeding
- Weight1: weight [g] on start date of experiment
- Standard_length1: length [cm] on start date of experiment (snout to the base of the caudal fin)
- absolut_size1: length [cm] on start date of experiment (snout to the end of caudal fin; total size)
- BCI: body condition index
- LAB_tailfin: LAB values of the tailfin on start date (chromaticity (LC)= √(a^2+b²))
- LAB_ventral: LAB values of the belly/ ventral side on start date (chromaticity (LC)= √(a^2+b²))
- LAB_tailfin2: LAB values of the tailfin on end date (chromaticity (LC)= √(a^2+b²))
- LAB_ventral2: LAB values of the belly/ ventral side on end date (chromaticity (LC)= √(a^2+b²))
- Cave_occupied: Did individual occupy cave during the experiment? Yes=1, No =0
Code/software
All statistical analyses was conducted in R 4.0.3
Access code file (Inbreeding_P.taeniatus_clean.Rmd) here: https://datadryad.org/stash/downloads/zenodo_file/3817257?share=7ro-vLe9O-k3yYtlkc4A-g0FHXnReOpXaa9VXMynBig
Packages:
lme4, Version 1.1.35.5
lmerTest, Version 3.1.3
sjPlot, Version 2.8.17
Graphs produced using GrapheR
Package GrapheR, Version 1.9.86.5
Methods
Experimental animals/ procedure
The study animals were adult male Pelvicachromis taeniatus. In- and outbred P. taeniatus from the third generation of laboratory-bred fish were used. Inbred lines resulted from full-sibling breeding. Outbred fish originated from mating between unrelated individuals. All individuals were bred at the Institute of Evolutionary Biology and Ecology of the University of Bonn. In the experiment, 24 inbred and 24 outbred adult male P. taeniatus originating from 11 inbred and from 7 outbred families were used.
Five outdoor tanks were used during this experiment, which allowed us to simultaneously conduct five trials. Three adult male P. taeniatus (i.e., two unfamiliar, related individuals, and one unfamiliar unrelated individual) were separately transferred to each experimental. In one experimental tank, only one trio was introduced. In total, 8 inbred trios and 8 outbred trios were tested. In inbred trios, the unrelated fish originated from a different inbred line. We used only unfamiliar males to exclude dominance effects caused by previous interactions between males. All three fish were simultaneously released at the center of the tank. The fish were kept together in the tanks for three days without disturbance to give them the opportunity to build territories in the prepared ceramic caves. Before and after each trial, standard lengths (SL) of the males were measured (snout to the base of the caudal fin) and fish were weighted.To quantify the intensity of body coloration, photographs were taken using a standardized set-up including a photo box before and after each experiment.
Data analysis
To analyze the intensity of coloration, the program Adobe Photoshop CS4 Extended (Version 11.0.2) was used. The coloration was measured in form of Lab-values by applying the CIELab color space, which is commonly used to study fish coloration. CIELab values separate contrast (L*) from color (a*, b*). Ten points at the caudal fin and ten points at the ventral body area were determined to quantify the yellow coloration. The Lab-chromaticity value was calculated by applying the formula: 𝑐ℎ𝑟𝑜𝑚𝑎𝑡𝑖𝑐𝑖𝑡𝑦 = √𝑎² + 𝑏²
Statistical analysis
Data were analyzed using the software R 4.0.3. Color variables (chromaticity caudal fin coloration and chromaticity ventral coloration) were analyzed by conducting LMEs using the lme4-package. The effects of inbreeding and brother presence on the yellow color intensity (after the experiment) at the ventral body area and the caudal fin were investigated by LMEs. All predictor variables were binary. The initial color intensity was added as co-variate to control for significant differences in coloration among the fish before the experiment. We furthermore tested an interaction between the effects of inbreeding and the presence of a brother. As random factors, the family and the male group ID were included into the LMEs to control for multiple uses of families and group effects. Non-significant variables were removed stepwise from the LMEs in the order of their statistical relevance using the backward elimination procedure of the step function in the lmerTest package. To investigate the effects of inbreeding and kinship on the dominance behavior, we conducted a LME using inbreeding and brother present as explanatory variables and cave occupation as response variable. Again, we also tested the interaction between the effects of inbreeding and kinship. The same random effects were used.