  In freshwater ecosystems, aquatic insects that ontogenetically shift their
habitat from aquatic to terrestrial play vital roles as prey subsidies that
move nutrients and energy from aquatic to terrestrial food webs. As a result,
these subsidies negatively affect alternative terrestrial prey by enhancing
predator density. However, these aquatic insects can also transport
contamination to the terrestrial community that is primarily produced in
aquatic ecosystems. Which can reduce insectivore abundance and biomass, lower
insectivore reproductive success, and increase predation pressure on
alternative prey with consequences for aquatic and terrestrial food webs.
Motivated by this, here we consider a prey-predator model where the predator
consumes contaminated and uncontaminated prey together. We find that, at a high
level of contamination, the vulnerability of contaminated prey and predator is
determined by predation preference. More specifically, a very low predation
preference towards contaminated prey ensures predator persistence, whereas a
low, high preference excludes the predator from the system. Interestingly,
either contaminated prey or the predator exist at intermediate predation
preference due to bi-stability. Furthermore, when there is no contamination in
one of the prey, the other prey can not coexist due to apparent competition for
a specific range of predation preferences. However, when sufficient
contamination exists in one prey, alternative uncontaminated prey coexists.
With this, contamination also stabilizes and destabilizes the three species
dynamics. Our result also indicates that if the intensity of the contamination
in predator reproduction is low, then contaminated prey is more susceptible to
the contamination.
