Plant virus infection modifies plant pigment and manipulates the host preference behavior of an insect vector

Insect-borne plant viruses may modify the phenotype of their host plants and thus influence the responses of insect vectors. When a plant virus modifies host preference behavior of a vector, it can be expected to influence the rate of virus transmission. In this study, we examined the effect of Maize Iranian mosaic virus (MIMV) infection on host preference behavior of the nymphs and adults of its vector, the small brown planthopper, Laodelphax striatellus Fallén (Hemiptera: Delphacidae), feeding on barley plants (Hordeum vulgare L., Poaceae). We found that both viruliferous nymphs and adults significantly preferred healthy plants, whereas non-viruliferous planthoppers preferred virus-infected barley. Further investigations revealed significant reductions in the chlorophyll and carotenoid contents of infected barley leaves. Based on these results, a possible association between insect host preferences and the pigment contents of the plants was observed. In summary, we suggest that host preference of L. striatellus could be affected by the propagative plant virus, possibly through association of this modification with some phenotypic traits of infected plants. These effects may have a critical impact on MIMV transmission rate, with significant implications for the development of virus epidemics.