Plant viruses alter insect behavior to enhance their spread

TLDR

Pathogens can manipulate host or vector behavior to increase transmission, and in plant systems this manipulation is mainly observed in mobile vectors whose plant preferences depend on the infection status of the host. The authors introduce the Vector Manipulation Hypothesis to explain how plant pathogens evolve strategies that enhance their spread to new hosts. They demonstrate that Barley yellow dwarf virus–infected aphids preferentially feed on healthy wheat while uninfected aphids favor infected plants, a behavioral shift that promotes both acquisition and transmission and has implications for disease and vector management.

Abstract

Pathogens and parasites can induce changes in host or vector behavior that enhance their transmission. In plant systems, such effects are largely restricted to vectors, because they are mobile and may exhibit preferences dependent upon plant host infection status. Here we report the first evidence that acquisition of a plant virus directly alters host selection behavior by its insect vector. We show that the aphid Rhopalosiphum padi, after acquiring Barley yellow dwarf virus (BYDV) during in vitro feeding, prefers noninfected wheat plants, while noninfective aphids also fed in vitro prefer BYDV-infected plants. This behavioral change should promote pathogen spread since noninfective vector preference for infected plants will promote acquisition, while infective vector preference for noninfected hosts will promote transmission. We propose the "Vector Manipulation Hypothesis" to explain the evolution of strategies in plant pathogens to enhance their spread to new hosts. Our findings have implications for disease and vector management.