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This dialog box let you tune the mating system, that is, how individuals should be associated before meiosis.

Mating group size : The mating group size assumes that individuals cannot meet the whole population. It therefore controls for the variation in phenotype that each individuals can access to choose a mate. In a two-sex model, it would be akin to operational sex-ratio.

Fecundity : The fecundity indicates how will be calculated the number of offspring obtained from a given mating. Currently, the number of offspring is related to either the mean of both parents's gametic investments, or to the minimum of these two values. The first option is a sensu lato vision of gametic investment (it could for instance include energy included in gametes, or parental care), whereas the second one is strictly constrained to the sheer number of possible meiosis.

Encounter model: how individuals encounter each other in the mating group.

Random encounter : associates random pairs of available individuals in the mating group until all sexual partners have mated (or all but one if the mating group is not a pair number).

Competitive encounter : individuals from the same mating group ( and with opposite sex, if sex is represented) encounter each other based on their value of competitiveness. The probability that two individuals forme a pair depend on the product of the individuals competitiveness. For instance the two individuals with higher competitiveness will encounter first (and then mate or not), then among the remaining individuals the 2 most competitive individuals will encounter, etc.. Note that if the meeting is not followed by a mating, each individual will be still available for mating. When individuals have mated once however, they are not available for further mating for the current time step and are removed from the list. Consequently, the less competitive individuals may miss reproduction if all opposite sex partners in the mating group have already mated ( when mating group is not a pair number).

Preference model : how individuals take the decision to mate.

Random mating : formed paired during the encountered process automatically mate. This approach intrinsically assumes that no energy is wasted in the mate search process: the preference trait has therefore no impact on the outcome (and no selection is thus acting on it).

Fixed threshold : individuals can only mate with another individual whose gametic investment is strictly above the preference threshold value. This value is genetically coded. This option assumes that some individuals are more choosy and that being choosy is costly.

Probabilistic threshold : the probabilistic threshold model assumes that individuals can detect more or less efficiently the gametic investment of potential mates, according to their preference. An individual having a high value of preference will therefore be picky and will try to choose a sexual partner with a high value of phenotype, but the outcome can still be a low value of phenotype. An individual with a low value of preference will not be choosy, and will accept more easily low gametic investment.

Unimodal preference: prefer a particular value of the gametic investment with a tolerance around this value ($\nu$). The closer the gametic investment of the partner met is to the individual's preferred value, the higher the probability that the individual will accept the mating (fig.~\ref{fig_acceptanceProba}). The parameter $\nu$ is set to $0.2$ so that the integral of the preference function for an individual preferring a particular value of the gametic investment of 0.5 is equal to 0.5

The behavioral routine will cycle through the population until all individuals have mated, or if a limit value in routine cycles number is reached (see Control dialog box). Note that only the third and fourth options are actually costly, because they involve genetic control and preference expression. They also have a possible additional cost, increased for choosy individuals: they may not find their mate if they spend to much time (routine cycles here) before less choosy individuals mate between each other.

Choice :

Mutual Choice: Mating only occurs if both individuals agree.

/female choice: if two sexes are considered, we can choose that females only choose their mate. Preference span : The strength of preference can be either expressed on the whole genetically possible range of phenotype (or gametic investment), or on the range of available phenotype (or gametic investment) in the mating group. This option is very important: in the first case, it implies that all individuals are somewhat all-knowing, or that their ability to distinguish between mates is not influenced by social environment (local availability of phenotypes). The second case on the opposite implies that the locally available phenotypes define the whole span of preference expression, whatever the actual range of variation in phenotype. It also means that individuals can actually clearly distinguish between two very similar phenotypes. Usually, the second option will strongly speed up evolution. Preference cost : preference has a cost on survival or no. Sexe : Are there two separate sexes (male and female)? If not, any two individuals can reproduce together. Sexual chromosomes : if there are two separate sexes, are there separate chromosomes for each sex?

help_en/runaway/gui/runinitmating.txt ยท Last modified: 2020/03/20 10:26 by louise-chevalier