The interactions of vector-virus-plant have important ecological and evolutionary implications. In this presentation, I will use the case studies on the whitefly vectors, begomoviruses, and plants to illustrate the complexity, consequences and mechanisms of this type of tripartite interactions. The interactions between begomoviruses and their whitefly vectors via their shared host plants can be mutualistic, neutral or negative depending on the species/strains of each type of the organisms involved. With regard to the mechanisms of plant-mediated positive effects of the viruses on whiteflies, three case studies indicate that suppression of jasmonic acid/salicylic acid related plant defence plays an important role. Our recent studies show that the order of arrival of the interacting vector insects and viruses on the plants may also alter the physiological feature and consequences of the interactions. Future efforts in this area should try to expand the number and diversity of case studies in order to reveal the patterns of interactions, to unravel the molecular and biochemical mechanisms of the interactions using a multidisciplinary approach, and to examine the virus-plant-vector interactions in the field and in natural plant communities.

Plant-feeding insects are a ubiquitous feature of terrestrial life. It follows that understanding the evolution of insect herbivory and its diversity is fundamental to understanding the evolution of terrestrial ecosystems. During my Ph. D. study, I found phylogenetic conservatism in the feeding mode (internal vs. external feeding) of Yponomeutoidea, one of the primitive lepidopteran superfamilies, as well as in their diet breadth and in the growth form and taxonomic affinities of host plants they used. In spite of their importance in terrestrial ecosystems, the evolutionary history of Lepidoptera has been poorly known. This mostly is attributable to their poor fossil record. My Ph. D. study provided better understanding to the lepidopteran fossils. Fossils are an essential resource in divergence time estimation using molecular clock methods. Once reliably resolved, dating data can be used in tracing the evolutionary history of Lepidoptera/plant associations. I introduce my works to take such advantages from fossils and phylogenetic studies.