DOI: 10.5061/dryad.9zw3r22p1
title: Alternative reproductive tactics and evolutionary rescue

description: Almost all life on earth is facing environmental change, and understanding
 how populations will respond to these changes is of urgent importance. One
 factor that is known to affect the speed by which a population can evolve
 when faced with changes in the environment is strong sexual selection.
 This increases the adaptive capacity of a population by increasing
 reproductive skew towards well-adapted (usually) males who will, on
 average, be best able to compete for matings. This effect could
 potentially be disrupted when males pursue alternative reproductive
 tactics (ARTs), whereby males within a species exhibit qualitatively
 different behaviours in their pursuit of matings. ARTs are diverse but one
 common class is those expressed through condition-dependent polyphenism
 such that high-quality, well-adapted males compete aggressively for mates
 and low-quality, poorly adapted males attempt to acquire matings via
 other, non-aggressive behaviours. Here, using an individual-based
 modelling approach, we consider the possible impacts of ARTs on adaptation
 and evolutionary rescue. When the ART is simultaneous, meaning that
 low-quality males do engage in contests but also pursue other tactics,
 adaptive capacity is reduced and evolutionary rescue, where a population
 avoids extinction by adapting to a changing environment, becomes less
 likely. This is because the use of the ART allows low-quality males to
 contribute more maladaptive genes to the population than would happen
 otherwise. When the ART is fixed, however, such that low-quality males
 will only use the alternative tactic and do not engage in contests, we
 find the opposite: adaptation happens more quickly and evolutionary rescue
 when the environment changes is more likely. This surprising effect is
 caused by an increase in the mating success of the highest quality males
 who face many fewer competitors in this scenario—counterintuitively, the
 presence of males pursuing the ART increases reproductive skew towards
 those males in the best condition.
description: Data are outputs from simulation modelling.
description: # Alternative reproductive tactics and evolutionary rescue [Access this
 dataset on Dryad](https://doi.org/10.5061/dryad.9zw3r22p1∴) Dataset is a
 set of outputs from simulation modelling of the influence of the use of
 alternative reproductive tactics by males on adaptation rates and the
 likelihood of evolutionary rescue in a changing environment. The code for
 the model and for running simulations and visualising the results is also
 included. ## Description of the data and file structure There are four
 data files with model output. These are: **output_drectional_100reps.csv**
 Simulation output used for the analysis of extinction probability (figure
 2) **output_step_return_100reps.csv** Simulation output used for the
 analysis of return times after step change (figure 3)
 **output_effect_size_100reps.csv** Simulation output used for the analysis
 of Critical Rates of Environmental Change (Supplementary material)
 **output_ART_success_100reps.csv** Simulation output used for the analysis
 of the effect of increasing the success of males following the ART
 (supplementary material) All of them but output_step_return.csv have the
 following variables: *K*_cap the carrying capacity of the environment
 *group_size* the size of the group foals from which females make a choice
 *max_offspring* the maximum number of offspring a female can have in a
 single breeding season *alpha* the cost of expressing a display trait
 *ART_success* a variable which adjusts the probability of a male pursuing
 the ART gaining a mating *threshold* the condition threshold below which a
 male will pursue the ART *type* the kind of ART: simultaneous or fixed
 *beta* a variable controlling the strength of female preference *rep* the
 replicate number *extinct* whether the population became extinct (1 =
 extinct, 0=persists) *time_to_extinct* if the population became extinct,
 the timestep when this happened output_step_return.csv has K_cap,
 group_size, max_offspring, threshold, type, beta, rep and also
 *return_time* the time taken for the population to adapt to a new
 environment following a step change in the environment. ## Sharing/Access
 information These data etc. are also archived on GitHub *
 [https://github.com/rjknell/Alternative_tactics_model](https://github.com/rjknell/Alternative_tactics_model) ## Code/Software Two R scripts are included: **Alternative_tactics_model.R** this is the code for the model itself. **ART_sims_and_analysis.R** this script has code for running the simulations and for visualising the data. Both scripts were developed and run in R 4.3.0 The model code requires the moments package. The code for running simulations and data visualisation requires the following packages: doParallel foreach dplyr ggplot2 moments readr MASS