Visual attraction to infected plants by aphid vectors and their predators affects disease dynamics: A simulation study

Background/Question/Methods  

Many plant viruses induce a color change in the host turning plant tissues yellow. Because aphid vectors and in some cases predators of aphids are attracted to yellow colors, virus induced yellowing can also influence the spatial and temporal distribution of both aphids and their predators. This in turn has the potential to influence the disease dynamics of the aphid transmitted virus. We used a spatially explicit stochastic simulation inspired by integrodifference models to understand how virus dynamics are affected by the dispersal behavior and predator-prey dynamics of aphids and their predators. 

 

Results/Conclusions  

Logistic regression analysis shows that the probability of a plant becoming infected is significantly affected by aphid and predator attraction to infected plants, as well as the number of nearby plants which are infected.  Predator-prey cycling also influences disease spread.  Rate of virus spread goes in cycles with rapid bursts of new infections interspaced with periods with slower virus spread.  Probability of a plant becoming infected is significantly increased by the population levels of aphids (infectious or not) nearby and significantly decreased by nearby predators.  This suggests aphid population booms are important for the spread of aphid vectored diseases and that during these booms aphid attraction to infected plants may serve to speed the rate of spread by maximizing the aphid population carrying the virus.  These interactions between dispersal behavior and population dynamics have important implications for management of aphid vectored diseases.