Frankliniella occidentalis (Pergande) feeding behavior is altered by Tomato spotted wilt virus (Bunyaviridae, Tospovirus) infection

Specific components of insect feeding behavior are critical to their competency in transmission of plant viruses. Although most feeding behaviors of piercing/sucking insects are not readily visible because they occur within plant tissues, the electrical penetration graph technique allows examination of insect feeding in real time and has been used extensively for aphids, leafhoppers and whiteflies. Very few studies have been done with thrips due to difficulties associated with their minute size; however, differences in the feeding of males and females have been noted, and researchers have often observed that males are more efficient transmitters of Tomato spotted wilt virus than females. We show that not only do male and female Western flower thrips (Frankliniella occidentalis) differ dramatically in their feeding behavior, but infection with TSWV, a persistently transmitted, propagative virus, results in significant changes to their interactions with the plant host. Specifically, our data reveal that viruliferous males make more feeding and exploratory probes, and spend more time ingesting individual cells than non-viruliferous males over an eight hour period. Furthermore, viruliferous male feeding behavior more closely resembles female feeding behavior, which did not differ between viruliferous and non-viruliferous females. While several studies show that infected plants alter vector feeding preference and survival, this is the first study that we are aware of to report a change in the feeding behavior of a plant virus vector due to viral infection. The implications of these finding to transmission of TSWV will be discussed.