Predator biocontrol
We simulated varying rates of snail host mortality representing
predators as biocontrol agents feeding on hosts based on their body size
under different predator densities. We used 22 predator densities of
0ā50 N mā2, extending beyond realistic densities
used in aquaculture of congeneric species and field experiments of prawn
predation on schistosome host snails (Sokolow, Lafferty, and Kuris
2014).
We simulated two scenarios of host mortality by predators,discrete host mortality and continuous host mortality . The
discrete risk scenario represents predation exclusively on individuals
falling within a given size range in which a lower bound of this size
range at zero represents gape-limited predation. In contrast, the
continuous risk scenario represents predation risk as a decreasing
function of host size, consistent with laboratory studies on
size-selective feeding of snail hosts by prawn predators (Sokolow,
Lafferty, and Kuris 2014). Hosts not consumed by predators died
naturally at baseline mortality rates (hazard rate,hb = 0.001 dĀā1).