Effects of predator modulation and vector preference on pathogen transmission in plant populations

Biological control programs frequently rely on predators to control vector-borne pathogens by consumptive effects on vector abundance in agroecosystems. Meanwhile, the spread of vectored disease depends on the vector preference for host status (healthy or infected hosts). Yet, it is unclear how vector preferences alter the controlled effectivity of predators in pathogen transmission. Therefore, we here addressed the plant-vector-pathogen models assessing how pathogen transmission in plant was affected by variable predation rates and vector preferences for host status. Specifically, we discussed effects of predators on vector abundance and pathogen transmission under both a non-spatial model and a spatially structured metapopulation model. We showed that predators can decrease the vector abundance and inhibit pathogen prevalence, whereas vector preference contributes profoundly to the controlled effectivity of predators on the spread of vector-borne pathogens. Moreover, predation can increase oscillation amplitude of the pathogen prevalence in both plant and vector; suggesting that the inclusion of predator can amplify the effects of environmental stochasticity on pathogen dynamics. In conclusion, our results support the prediction of theoretical disease models showing predator can be a natural enemy for pathogen control, and also extend that predatory interactions interacting with vector preferences play the singularly joint effects on the spread of vector-borne pathogens.