Infection with a plant virus modifies vector feeding behavior

TLDR

Vector infection by parasites, including Bunyaviridae members, can alter feeding behavior, enhancing transmission—a broadly adaptive trait. The study investigates whether Tomato spotted wilt virus infection changes the feeding behavior of its thrips vector, Frankliniella occidentalis. The authors examined feeding behavior of TSWV‑infected versus uninfected Frankliniella occidentalis thrips, quantifying feeding bouts and probing patterns. TSWV‑infected male thrips exhibited up to a threefold increase in all feeding behaviors, including nearly three times more noningestion probes, thereby raising the likelihood of virus inoculation and supporting the conserved role of vector behavioral modification in Bunyaviridae transmission.

Abstract

Vector infection by some animal-infecting parasites results in altered feeding that enhances transmission. Modification of vector behavior is of broad adaptive significance, as parasite fitness relies on passage to a new host, and vector feeding is nearly always essential for transmission. Although several plant viruses infect their insect vectors, we have shown that vector infection by a plant virus alters feeding behavior. Here we show that infection with Tomato spotted wilt virus (TSWV), type member of the only plant-infecting genus in the Bunyaviridae , alters the feeding behavior of its thrips vector, Frankliniella occidentalis (Pergande). Male thrips infected with TSWV fed more than uninfected males, with the frequency of all feeding behaviors increasing by up to threefold, thus increasing the probability of virus inoculation. Importantly, infected males made almost three times more noningestion probes (probes in which they salivate, but leave cells largely undamaged) compared with uninfected males. A functional cell is requisite for TSWV infection and cell-to-cell movement; thus, this behavior is most likely to establish virus infection. Some animal-infecting members of the Bunyaviridae ( La Crosse virus and Rift Valley fever virus ) also cause increased biting rates in infected vectors. Concomitantly, these data support the hypothesis that capacity to modify vector feeding behavior is a conserved trait among plant- and animal-infecting members of the Bunyaviridae that evolved as a mechanism to enhance virus transmission. Our results underscore the evolutionary importance of vector behavioral modification to diverse parasites with host ranges spanning both plant and animal kingdoms.