Evolution of signal production under various levels of signal costs and colony bottleneck sizes.

<p>The plots show the amount of signal that is present in a population of cells that evolved for 550.000 time steps for different values of (plot A) and (plot B). The grey area shows the standard deviation. For every parameter setting, 50 independent runs were studied. ‘Signal’ gives the average amount of signal that is present in the environment per time step and colony. is the reduced chance of having cell division. Thus, is equal to a 2% lower chance of having cell division. Notice that the maximum chance of having cell division is 10% (). is the number of individuals that initiate a colony and hence the bottleneck size. For plot A we assumed that and for plot B we assume that . Thus, the runs of plot B at are performed under the same parameter settings as those of plot A at . The relatively large standard deviation in plot B can be explained by the co-existence of multiple communicative strategies, of which some produce signal, while others do not. Since the abundances of these strategies change over time, the amount of signal that is being present differs strongly between the runs. Furthermore, in some runs cell-to-cell communication does not evolve (e.g. at high values of ). The other parameter settings are the following: , , , , , , , , , , , , , , and .