Comparative evaluation over time during mate choice in the green swordtail Xiphophorus hellerii
Data files
Sep 17, 2025 version files 108.15 KB
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AllSeqData.csv
15.14 KB
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BodySizeDataKathrynALLplusgaps.csv
60.83 KB
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README.md
4.54 KB
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SimSeq_Code_FINAL_(1).R
27.64 KB
Sep 17, 2025 version files 108.15 KB
-
AllSeqData.csv
15.14 KB
-
BodySizeDataKathrynALLplusgaps.csv
60.83 KB
-
README.md
4.54 KB
-
SimSeq_Code_FINAL_(1).R
27.64 KB
Abstract
During mate choice, choosers are exposed to a variety of sexual signals varying in both magnitude and the environment in which they are experienced. Previous work assumes that choosers evaluate signal variation from potential mates that are simultaneously viewed and compared. However, this is an extreme scenario, and it is important to also consider sequential presentation of mates, as most animals likely experience both scenarios during mate choice. Using green swordtail fish (Xiphophorus hellerii), we assessed whether female preferences for larger males differed when males of different sizes were experienced simultaneously or sequentially. We also investigated the perceptual mechanisms of comparison in both contexts, given recent research suggesting that female preferences are often non-linear. We found that females consistently preferred larger males, irrespective of whether males were experienced simultaneously or sequentially. However, female preferences were stronger for a male of a given size when viewed under simultaneous, compared with sequential, conditions. During sequential presentation, females compared information from both previously and currently presented males, and interest did not decay with subsequent presentations. Previous research has demonstrated that female green swordtails assessing males simultaneously attend to the relative size difference between males, but we found no evidence of any comparative size assessment. Our study demonstrates that when designing mate choice experiments, it is important to consider how females encounter potential mates in the wild, highlighting that there are clear differences in preferences due to methods of mate presentation and that stochastic adjusting of internal standards of quality frequently occur.
Dataset DOI: 10.5061/dryad.jwstqjqp7
Description of the data and file structure
This project concerns an investigation into how female green swordtail fish perceive male mate stimuli when presented in both a simultaneous and sequential context. Virtual images of male swordtails of differing body sizes were presented to the females both simultaneously and sequentially, in order to assess, based on association time, whether their strength of preference for larger males differed based on the type of presentation. The perceptual mechanisms of comparison over both types of presentation were also investigated, given recent research suggesting that female preferences are often non-linear.
Analysis of the associated datasets confirms that female swordtails do generally prefer larger males, however this preference is stronger under simultaneous, rather than sequential, presentation. Previous research has demonstrated that female green swordtails assessing males simultaneously attend to the relative size difference between males, however we found no evidence of any comparative size assessment in this study.
Data was collected between Feb-Oct 2023 at the Centre for Ecology and Conservation, University of Exeter.
Files and variables
File: SimSeq_Code_FINAL_(1).R
Description: Complete annotated R code for replicable statistical analysis of the associated data, as well as the replication of all graphical figures. Packages required: ‘dplyr 1.1.4’, ‘tidyr’ 1.3.1, ‘ggplot2’ 3.5.1, ‘Rmisc’ 1.5.1, ‘lme4’ 1.35.5, ‘lmerTest’ 3.3, ‘ggpubr’ 0.6.0, ‘rptR’ 0.9.22, and ‘MuMIn’ 1.48.4.
File: AllSeqData.csv
Description: Data associated with the sequential presentation of male stimuli to female green swordtails.
Variables
- filename: Female fish ID code
- Order: Presentation order of the associated male stimuli
- MaleStim: The body size of male stimuli being presented to the female fish, denoted as a percentage value of the original 100% mean male stimuli (body length 44mm, sword length 32mm)
- CenterDur: Time the female swordtail spent in the neutral central third of the experimental tank (seconds)
- MaleDur: Time the female swordtail spent in the third of the experimental tank where the male stimulus was being presented (seconds)
- FemaleDur: Time the female swordtail spent in the third of the experimental tank where the female dummy stimulus was being presented (seconds)
- MaleSide: Side of the tank where the male stimulus was being presented
- FemaleSide: Side of the tank where the female dummy stimulus was being presented
File: BodySizeDataKathrynALLplusgaps.csv
Description: Data associated with the simultaneous presentation of male stimuli to female green swordtails.
Variables
- Fish_ID: Female fish ID code
- Date: Date the experimental trial was run
- Comp_Num: Denoted comparison pair category number
- Comparison: The two male stimuli sizes being presented to the female swordtail simultaneously
- Stimulus: The body size of one of the male stimuli being presented to the female fish in a simultaneous trial, denoted as a percentage value of the original 100% mean male stimuli (body length 44m, sword length 32mm)
- Area_large: Body area of the larger male stimuli in the comparison pair (mm^2)
- Area_small: Body area of the smaller male stimuli in the comparison pair (mm^2)
- Stimulus_Side: Side of the tank where the highlighted male stimulus (noted in the 'Stimulus' variable) was being presented
- Time_with_Stim: Time the female swordtail spent in the third of the experimental tank where the highlighted male stimulus (noted in the 'Stimulus' variable) was being presented (seconds)
- Latency_to_Visit: Time the female swordtail took to first enter the third of the experimental tank where the highlighted male stimulus (noted in the 'Stimulus' variable) was being presented (seconds)
- Visits_to_Stim: Number of visits the female swordtail made to the third of the experimental tank where the highlighted male stimulus (noted in the 'Stimulus' variable) was being presented
Code/software
All analyses were carried out using RStudio version 4.3.0 including packages ‘dplyr 1.1.4’, ‘tidyr’ 1.3.1, ‘ggplot2’ 3.5.1, ‘Rmisc’ 1.5.1, ‘lme4’ 1.35.5, ‘lmerTest’ 3.3, ‘ggpubr’ 0.6.0, ‘rptR’ 0.9.22, and ‘MuMIn’ 1.48.4.