Figure 3

Cumulative parasitic juvenile abundances through time where the proportion of tributaries treated each year equaled 0.05 (panel A), 0.1 (panel B), 0.2 (panel C), and 0.3 (panel D), respectively. TFM treatment was started at year 50 and a single resistant adult was introduced in year 70. One hundred replicates (dark blue lines) were run for each scenario. Red circles represent populations with at least one resistant individual at year 200 and grey circles represent populations with no resistant individuals. The total number of simulations (out of 100) where no resistant individuals survived to year 200 are reported in the bottom right of each panel (“not resistant”). The solid horizontal line equals the mean number of parasites at year 200 where 5% of tributaries were treated each year (plotted on all panels, but measured from panel A). The dashed horizontal line represents the mean number of parasites at year 200 for each additional treatment intensity. Notice that when resistance evolves, higher treatment levels of TFM treatment do not substantially decrease the total number of parasites in the system over the long run. If resistance never evolves (grey circles), TFM will continue to be an effective management tool.