Fatal attraction of non-vector impairs fitness of manipulating plant virus

1. Host manipulation refers to the expression of a host phenotype that is partly under the genetic control of a parasite. This phenomenon can enhance parasite transmission rates and is responsible for biological marvels such as 'Zombie-ants' and the 'fatal attraction' of Toxoplasma-infected rodents to their feline predators. Such host manipulation has evolved in all major phylogenetic lineages of parasites and is assumed to enhance the fitness of the parasite.
2. However, the capacity to manipulate is not ubiquitous; that is, many clades of parasites comprise manipulating and non-manipulating species. This pattern leads to the prediction of costs that select against the evolution of manipulation, but this has been difficult to show empirically.
3. In the present study, we used a tripartitate system consisting of chili (Capsicum annuum) plants infected with Pepper golden mosaic virus and colonized by non-vector whiteflies (Trialeurodes vaporariorum), to study the effects on viral load...