Spatio-temporal dynamics of vectors of Xylella fastidiosa subsp. pauca across heterogeneous landscapes

Xylella fastidiosa subsp. pauca is a plant pathogen that causes the Olive Quick Decline Syndrome, the spread of which is linked to insect vectors. Since these vectors can use and move across multiple managed and natural habitats, understanding their occurrence in different habitat types at the landscape scale is particularly challenging. Here, we applied a bipartite network approach to explore the spatio-temporal distribution of confirmed and potential vectors of X. fastidiosa in olive groves. We sampled sharpshooters and spittlebugs in 10 heterogeneous landscapes in southern Italy during spring, summer, and autumn. In each landscape, we sampled insects in the main habitat types, i.e., arable land, grassland, olive grove, vineyard, and woodland. We then built and analyzed the resulting bipartite species–habitat networks. The abundance of vectors in different habitat types throughout the seasons varied from species to species, with Philaenus spumarius, the main vector of X. fastidiosa, being mostly collected in olive groves. However, the analysis of habitat specialization showed that P. spumarius acted as a super-generalist species, occupying all the habitats. Insect vectors in olive grove patches were strongly influenced by other olive grove patches in the landscape and also by grasslands, particularly in spring, therefore highlighting the focal role of non-crop habitats on potential pathogen spread. Landscapes dominated by olive orchards and grasslands seemed to provide the most suitable conditions to support large vector populations. Network analyses helped untangle the complex interactions between vectors of X. fastidiosa and the landscapes and habitats they use.