Try these parameter values:
No Heritability
#generations= 10
heritability=0
#territories=9
heterogeneity=0%
Heritability, Small Number of Territories
#generations= 10
heritability=1
#territories=100
heterogeneity=0%
Heritability, Large Number of Territories
#generations= 10
heritability=1
#territories=100
heterogeneity=0%
Large Number of Generations
#generations= 30
heritability=1
#territories=9
heterogeneity=0%
Male-Male Competition can lead to extravagant male characters and sexual size dimorphism. Typically, males will compete for territory (in which body size or ornament characteristics will determine their ability to compete) and females will choose males based on the territory they possess. Males that are able to maintain larger territories of good quality will tend to aquire more mates and will therefore be more represented in the next generation. It is important, however, that differences in the ability to compete are genetically determined (heritable). Likewise, female preference for males/territories must also have heritable variation. Females choose territories that will maximize thier reproductive output. Territory quality is often correlated with size per female.
In general, the more limited the territories are in number and quality, the stonger the selection for extravagant male characters and sexual size dimorphism. The degree of territory heterogeneity (both size and quality) can also affect the strength of sexual selection: the more heterogeneous, the stronger the selection. The reason for this is that female choice is more important if differences exist in their reproductive output.
Adjust the parameters to the right:
The population represented to the right consists of 100 males (only some of which breed) and 100 females (all of which breed). The genetically determined traits are: body size, male territory preference, and female territory preference.
The body size gene is expressed in males only (all females have the same phenotypic body size). The male territory preference gene determines if a particular male will attempt to fight for a particular territory or not (based on territory size). The female territory preference gene determines if the female will mate with the dominant male of a particular territory or not (based on territory size).
Territories are redrawn at the beginning of each generation. Males then move from territory to territory attempting to establish dominance. Males which do not establish dominance do not mate. Females arrive and survey the territories based on size, choosing a territory that is large enough based on their preference. Dominant males then mate with all females in their territory.
All traits follow a normal distribution. If the traits are heritable, then the average between mother and father is used as a mean for their offspring. Variance in a trait for a breeding pair is constant, although the variance of the whole population may change. If the trait is not heritable, the mean used initially is used througout to determine offspring trait values.
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