Figure 2.

Toxin-producing (blue and black) and nonproducing (red and grey) isolates of Staphylococcus epidermidis invading populations of S. aureus (SH1000) at frequencies of 0.1 (triangle), 0.01 (square) and 0.001 (circle). Toxin-producing S. epidermidis isolates (155 and 180) and nonproducing S. epidermidis isolates (035 and 115) were introduced into a population of S. aureus (SH1000) at three different frequencies. This was carried under a spatially structured regime (A and B) and under a mixed regimen (C and D). The x-axis is the time in days, and the y-axis is the natural log of the invader to resident ratio. A dotted line in the time course shows when the population dipped below the experiment detection threshold (for clarity, these lines also cross the x-axis if the population went to extinction). There is a heavy dotted line at 0 on the y-axis to indicate an equal invader to resident ratio. The line crossing the x-axis symbolizes that the population went to extinction. Error bars represent the standard error of the mean (n = 3).