ERC consolidator project BeePath: With this project, we will study how the epidemiology and evolution of viral bee pathogens are affected by the introduction of vector-borne transmission.
The emergence of novel transmission routes can have profound impact on the ecology and evolution of infectious diseases, with potentially dramatic effects on host populations. This can be particularly drastic when transmission changes from direct to vector-borne transmission, where prevalence and virulence are expected to increase. Despite its importance for disease prevention and control, we lack empirical and theoretical understanding of this process. The emergence of Varroa destructor in honeybees provides a unique opportunity to study how a novel vector affects pathogen ecology and evolution: this blood-feeding mite is a novel vector for Deformed Wing Virus (DWV), a disease linked to severe increases in hive mortality. To study the fundamental evolutionary ecology of emerging vector-borne diseases, we will exploit a unique natural experiment, the presence of Varroa-free island refugia, to test how this novel vector affects epidemiology and evolution in the field. Using this system, we have already shown that the acquisition of Varroa as a viral vector in honeybees has virus-dependent knock-on effects in wild bees (Manley et al. 2019, Ecology Letters; Manley et al. 2020, Molecular Ecology). We will adapt cutting-edge single molecule sequencing to compare viral evolution in the wild and in controlled lab experiments, where I will establish novel reverse genetics approaches in DWV to test hypotheses on specific viral genotypes. Like all emerging diseases, DWV is a multi-host pathogen that also infects wild bee species not infested by Varroa, such as bumblebees. This raises an additional question, highly relevant for zoonotic diseases: does this specialist honeybee vector impact disease in wild bee populations? This system will not only provide fundamental insights into the evolutionary ecology of disease, but is also of immediate applied importance: bees are key pollinators of crops and wildflowers, and halting population declines facilitated by infectious disease is crucial for food security and biodiversity. We will model the effect of vector acquisition and evolving pathogens on host populations and test potential prevention and mitigation strategies to safeguard these crucial pollinators.
A short movie (in german) about our work on vector-borne transmission in bees
3sat Wissen nano - Gefahr für Wildbienen
HealthyPollination: Together with Prof. Manfred Ayasse and Dr. Jonas Kuppler, we are studying how land use intensification, e.g. habitat fragmentation, decline in food sources and an increase in pesticide use can increase stress in insect pollinators, potentially leading to decreasing health. Decreasing pollinator health can in turn affect e.g. foraging behaviour, pollen loads carried and learning abilities of pollinators and thus may lead to changes in pollen transfer patterns and ultimately to a reduction in pollination services. Decreased health can also increase pathogen infection rate.
Within this project, we aim to understand the links between land use intensity, pollinator health and pollination services in grasslands. In order to achieve this aim, we will use the continuous land use index LUI, (Blüthgen et al. 2012) in combination with plot-level data on plant diversity and abundance (provided by core project 5 Botany) and data on land cover types surrounding the experimental plots (provided by core project 3 Instrumentation & Remote Sensing) as a measure for land use intensity. In all 50 grassland plots per exploratory, we will collect bumblebees and syrphid flies and assess several pollinator health indicators (i.e. cuticular lipids, viral loads and fluctuating asymmetry). Additionally, we will observe foraging behavior of bumblebees and syrphid flies in all 50 grasslands per exploratory.
The effect of agri-environment schemes on disease transmission dynamics in pollinator
We are currently working on a large BBSRC funded collaborative project with Royal Holloway and East Malling Institue investigating the impact of agri-environment schemes on emerging infectious diseases in pollinators.
Emerging diseases and the multi-host pathogens that cause them threaten animal and human health and can put ecosystem services at risk. Insect pollinators, particularly wild and managed bees, provide a key ecosystem service and are crucial for maintaining food security. But bees are in decline, and multiple lines of evidence suggest that emerging diseases may play a key role in these declines. Inter-specific transmission in pollinators is facilitated by niche overlap; sharing floral resources can promote indirect disease transmission. However, the provision of floral resources through agri-environment schemes is the key component in current programs to enhance pollinator assemblages for ecosystem services in agricultural landscapes. Based on this landscape-scale experiment, we are studying the fundamental ecology of disease transmission in this community to determine who and what drives transmission and how we can optimise management to reduce the risk of disease emergence. We are combining the study of disease transmission dynamics in the field with targeted experiments to dissect the drivers of disease transmission in agricultural landscapes.
The research team includes Dr. Robyn Manley and Toby Doyle at the University of Exeter as well as contributions from Owen Wright, Sophie Hedges and Meri Anderson; it is carried out in collaboration with Prof. Mark Brown (Royal Holloway University), Dr. Michelle Fountain (NIAB EMR) and Dr. Vincent Doublet (University of Edinburgh).