University of Liverpool
Ecology and Evolution

Cereal crops are grown for human consumption, livestock feed, and alcohol production. Herbivorous insects and plant diseases can significantly reduce crop yields, threatening food security. Barley yellow dwarf virus (BYDV) is a devastating cereal virus, with significant levels of infection reducing crop yields by up to 80%. BYDV is vectored by aphids, small phloem-feeding insects who’s needle-like mouthparts make them optimal virus vectors. In natural ecosystems individuals of all species are affected by others around them and these interactions can have wide-reaching consequences for organism biology and ecology. Despite this, virus- vector-host interactions are rarely studied in an ecosystem context and this lack of understanding limits the extent to which we can exploit natural processes to better manage virus infection. Studying interactions in a wider ecological context is important as subtle changes in the virus-vector-host system could have far-reaching consequences on vector behaviour and virus transmission. Aphid populations are genetically-diverse and host multiple endosymbiotic bacteria that confer dynamic benefits to host populations, including behavioural traits that could impact virus-vector biology; however, it is currently unknown if this diversity alters virus transmission ability. Additionally, vector-resistant plant varieties are often used to combat disease, although the bottom-up effect this has on the structure and behaviour of insect vector populations, and the knock-on impact on the spread of plant viruses in the local ecosystem, is unknown. It is also unknown to what extent the wider agro-ecological system, such as the presence of the natural predators and parasitoids of vector populations, exerts a top-down influence on the virus-vector-plant relationship, and whether this impacts virus transmission and success.

Filling these fundamental knowledge gaps will unravel the biological and ecological processes that underpin virus-vector-host interactions and will help us develop innovative and novel nature-based pest and disease management solutions. This fellowship will deliver this knowledge through three research objectives, each comprising a question centred on a fundamental knowledge gap. 1) How is virus transmission affected by insect vector diversity?; 2) To what extent does plant diversity influence the vector-virus relationship?; 3) Do natural enemies exert a top-down influence on the virus-vector-plant relationship and virus success?