DOI: 10.5061/dryad.jwstqjqp7
title: Comparative evaluation over time during mate choice in the green swordtail <em>Xiphophorus hellerii</em>

description: 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.
description: # Comparative evaluation over time during mate choice in the green
 swordtail *Xiphophorus hellerii* Dataset DOI:
 [10.5061/dryad.jwstqjqp7](https://doi.org/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.