Sensitivity analysis. (a) The factor by which increases compared to as a function of cumulative host mortality k (x-axis), in the presence of various "numbers" of alternate hosts. These "numbers" represent attractiveness of alternative hosts relative to 20 reservoir hosts. The presence of 20 alternative hosts, for example, corresponds to equal attractiveness of the alternative hosts when all reservoir hosts are still alive. The red curve corresponds to no alternative hosts available. The other curves, shown in yellow, green, blue and purple represent 5, 10, 20, and 100 alternative hosts available, respectively. (b) This graph shows the decrease in the biting rate a (k) relative to the initial biting rate a(0) (y-axis) as a function of cumulative host mortality k (x-axis) for which the number of mosquito bites per host remain unchanged, i.e. = . Points above the curve, but below 1 represent biting rates that decrease with increasing mosquito-host rates, but will still result in a net increase of mosquito bites per host.