DOI: 10.5061/dryad.1rn8pk173
title: Facultative polyandry under heat stress and the evolutionary potential for climate-driven shifts in mating systems

description: The ecology of mating interactions determines a species’ mating system,
 yet whether environmental change can alter the mating system of a species
 remains unclear. Elevated temperatures can cause male sterility, prompting
 females to remate for fertility assurance. In monandrous systems,
 heat-induced male infertility poses a significant extinction risk, as
 females may mate exclusively with infertile males. A key question is
 whether male sterility could drive polyandry in a typically monandrous
 system. Here we address this by examining genetic variance underlying both
 male fertility resilience to heat stress and facultative polyandry, and
 assessing the fitness consequences of each mating system. We used
 isofemales lines of Drosophila subobscura, a monandrous species, exposing
 males to developmental heat stress. Male heat stress generated sterility
 and females mated to these males typically remated. While significant
 genetic variation in male fertility sen sitivity and female remating
 emerged at moderate to high temperatures, we found little genetic
 variation in plasticity for polyandry. These results indicate evolutionary
 potential in both traits, but that a shift in mating system would arise
 through selection on genes associated with polyandry, rather than
 plasticity. Polyandry improved offspring production after initially mating
 to a sterile male, but did not fully restore reproductive output relative
 to fertile monandrous pairs, and mating with heat-stressed males increased
 female mortality. Heat stress also altered mating behaviour which could
 impact female mate choice. Together, these findings show that increasing
 temperatures may shape species’ mating systems and the interplay between
 thermal ecology and sexual selection under climate change.
description: # Facultative polyandry under heat stress and the evolutionary potential
 for climate-driven shifts in mating systems Dataset DOI:
 [10.5061/dryad.1rn8pk173](10.5061/dryad.1rn8pk173) ## Description of the
 data and file structure This repository archives the data and code
 associated with the manuscript titled, “Facultative polyandry under heat
 stress and the evolutionary potential for climate-driven shifts in mating
 systems”. There are 3 data sets (.csv) associated with this work and an R
 markdown script to support transparency and reproducibility: *
 **Mating.csv; Sterility.csv; Survival.csv**: The raw data used to generate
 the figures and tables in the paper. * **Pembury_Smith_et_al.Rmd**: A
 standalone R script that runs the models and produces the figures
 described and produced in the paper. Below is a breakdown of the files.
 ### Files and variables #### File: Mating.csv **Description:** Raw data
 used to examine the effect of male developmental temperature on male
 mating and female remating behaviour, as well as other behavioural traits
 (mating latency, copulation duration etc).  ##### Variables * Round:
 Experimental round (1 and 2) * Batch: Experimental batch (1-6) * Line:
 Isofemale line * Mate_T_treatment: Male temperature treatment (18 and 25
 degrees) * Mating: Whether mating occurred (0 = no, 1 = yes) *
 Mat_Lat_Min: Mating latency (mins) * Cop_Dur_Min: Copulation duration
 (mins) * Sterility: Whether an individual was sterile (Y = yes, N = no) *
 off_total: Total number of offspring produced * Remating: Whether a
 remating occurred (0 = no, 1 = yes) * Remating_latency_min: Remating
 latency (mins) * Copulation_duration_min: Remating copulation duration
 (mins) * Sterility_rm: Whether a remating was sterile (Y = yes, N = no) *
 r_off_total: Total number of offspring produced after remating #### File:
 Sterility.csv **Description:** Raw data used to examine the effect of
 temperature on male sterility.  ##### Variables * Experiment: Experiment
 (1 and 2) * Line: Isofemale line * Temp: Male temperature treatment (18
 and 25 degrees) * M_age: Male age when mated (days) * F_age: Female age
 when mated (days) * Mate: Whether mating occurred (Y = yes, N = no) *
 Sterile: Whether an individual was sterile (Y = yes, N = no) * cop_dur:
 Copulation duration (mins) * lat_min: Mating latency (mins) #### File:
 Survival.csv **Description:** Raw data used to examine the effect of male
 developmental temperature on female survival. ##### Variables * Round:
 Experimental round (1 and 2) * Batch: Experimental batch (1-6) *
 Collected: Date collected * Day: The day an individual died (0-49) or the
 day we stopped collecting survival data (50) * Event: Whether an
 individual died within 50 days of data collection (1 = yes, 0 = no) *
 Line: Isofemale line * Mate_T_treatment: Male temperature treatment (18
 and 25 degrees) * Mating: Whether mating occurred (1 = yes, 0 = no) *
 Sterility: Whether an individual was sterile (Y = yes, N = no) * Remating:
 Whether remating occurred (1 = yes, 0 = no) * Sterility_rm: Whether an
 individual was sterile after remating (Y = yes, N = no) * Combined:
 Categorical group where the first number is the male temperature treatment
 (18 and 25 degrees) and the second is whether they remated or not (0 = no,
 1 = yes) Note: Missing values are described as "NA" when a data
 value is not applicable or when data could not be collected for that
 individual.  #### File: Pembury_Smith_et_al.Rmd **Description:** R
 markdown file ### Code/software All analyses in this repository were
 performed using **R 4.2.2 **(R Core Team, 2024). Packages loaded before
 running the scripts are included in the code.