Anisogamy does not always promote the evolution of mating competition traits in males
Data files
Sep 18, 2023 version files 147.28 KB
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MATLAB_Scripts_-_dryad_20230918.zip
141.96 KB
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README.md
5.31 KB
Oct 03, 2023 version files 147.28 KB
-
MATLAB_Scripts_-_dryad_20230918.zip
141.96 KB
-
README.md
5.31 KB
Abstract
Anisogamy has evolved in most sexually reproducing multicellular organisms allowing the definition of the male and female sexes, producing small and large gametes. Anisogamy, as the initial sexual dimorphism, is a good starting point to understand the evolution of further sexual dimorphisms. For instance, it is generally accepted that anisogamy sets the stage for more intense mating competition in males than in females. We argue that this idea stems from a restrictive assumption on the conditions under which anisogamy evolved in the first place: the absence of sperm limitation (assuming that all female gametes are fertilized). Here, we relax this assumption and present a model that considers the coevolution of gamete size with a mating competition trait, starting in a population without dimorphism. We vary gamete density to produce different scenarios of gamete limitation. We show that, while at high gamete density the evolution of anisogamy always results in male investment in competition, gamete limitation at intermediate gamete densities allows for either females or males to invest more into mating competition. Our results thus suggest that anisogamy does not always promote mating competition among males. The conditions under which anisogamy evolves matter, as well as the competition trait.
https://doi.org/10.5061/dryad.0rxwdbrzs
MATLAB script, which provides a numerical solution of the stability analysis and gives the evolutionary trait evolution by solving the ODE of the canonical equation.
1. Workflow
Run the iso2aniso_main_230718_dryad.m file with MATLAB (version 2022b or later), according to one of the following three alternatives
1) Run iso2aniso_main_230718_dryad without input arguments solves the evolutionary path for a predefined parameter combination*
2) Run with adjusted parameter: iso2aniso_main_230718_dryad(fmc,Kg,Kz,d,am,ar)
Where
fmc = 0 |
runs the fusion partner capture competition trait |
fmc =-1 |
the chemoattraction competition trait |
fmc = 1 |
runs the motility competition scenario |
and
Kg |
determines the gamete size-survival parameter |
Kz |
determines the zygote size-survival parameter |
d |
determines gamete density constant |
ar |
determines the competition investment efficiency (for fusion partner capture and chemoattraction) |
am |
determines the size-dependent competition investment efficiency (for motility) or dimensionality of the competition trait (for fusion partner capture) |
The model parameter values will be adjusted to the closest tested value (see below).
3) Run with free parameters: iso2aniso_main_230718_dryad(fmc,Kg,Kz,d,am,ar,adjust)
Where adjust=true, the model parameter values are adjusted to the closest tested value, while adjust=false, the specified model parameters are unaltered.
Explanation:
The numerical solutions of the ODE can get unstable, especially for parameter regions being exactly between two regions of different evolutionary behaviour, or for extreme parameter values. The following code is adapted to handle the specific parameter combinations run for the figures produced in the manuscript (Fig. 4-5 and Fig S1-S2). Any other parameter combination could generate errors. By adjusting the chosen parameters to match the tested parameters, we can guarantee no errors.
Feel free to set adjust=false, but be aware that the numerical solutions might not work as intended. You can choose your own model parameters by specifying them as input arguments of the main function.
* Predefined parameter combination:
fmc = -1 |
Chemoattraction |
d = 1.5505 |
Gamete density constant, delta |
Kg = 0.1 |
Gamete survival constraint, K_g |
Kz = 1e4 |
Zygote survival constraint, K_z |
ar = 10 |
Competition investment efficiency, alpha_r |
Examples of other parameter combinations:
iso2aniso_main_230718_dryad(1,0.1,1e4,1e2 ,1,0) % Yields isogamy
iso2aniso_main_230718_dryad(1,0.1,1e4,1e-2,1,0) % Yields female bias
iso2aniso_main_230718_dryad(1,0.1,1e4,0.5 ,1,0) % Yields male bias
iso2aniso_main_230718_dryad(1,0.1,1e4,1.5 ,1,0) % Yields oscillations
2. Brief description of all files
1) iso2aniso_main_230718_dryad.m
Main file, determines the model scenario and parameters, as described above.
Performs all numerical analysis, solves ODE and plots the ODE-solution by running the remaining files in the given order below:
1.1) iso2aniso_eq_fmc_230615.m
With an input of 1, 0 or -1, the function will output a structure array with all equation needed for the scenario of motility competition, fusion partner capture competition or chemoattraction, respectively. The function will load all equations needed, if the corresponding MAT-file for the scenario is present. Otherwise, it will generate all equations, and then save them as a MAT-file, before returning them as a structure array.
1.1.1) iso2aniso_eq_fmc_230615_1.mat
MAT-file that contains all equations for the motility competition scenario.
1.1.2) iso2aniso_eq_fmc_230615_0.mat
MAT-file that contains all equations for the fusion partner capture competition scenario.
1.1.2) iso2aniso_eq_fmc_230615_-1.mat
MAT-file that contains all equations for the chemoattraction scenario.
1.2) iso2aniso_stabanalysis_iso_230718.m
Solves for the isogamic singular points and derives the stability properties of the evolutionary dynamics.
1.3) iso2aniso_odesolve_230626.m
Solves for the ODE, first under the isogamic constraint until attractor reached, and then for unconstrained evolution until anisogamic attractor is reached.
1.4) iso2aniso_stabanalysis_aniso_230615.m
Derives the stability properties of the evolutionary dynamics of the anisogamic attractor.
1.5) iso2aniso_plot_220921.m
Plots the ODE-solution.
1.5.1) breakxaxis.m
Function that split the data on the x-axis, such that is has a left and right range.
1.5.1) sfigure.m
Function that creates new figure window without cause a focus on the new figure.
1.5.1) sigdig.m
Function that rounds numbers to certain significance
2.1 Naming convention
A prefix of iso2aniso_ indicates that the function was created for this specific project. The six numbers in a row indicated year month and date of last edit _YYMMDD.
MATLAB script used for numerically solution of the stability analysis and ODE-solutions.
MATLAB (version 2022b or later)
