A century of genome diversity in UK insect pollinators

Pollinating insects are keystone species in almost all terrestrial ecosystems, playing a vital role in the reproductive success of both wild and cultivated flowering plants. However, pollinator populations have been declining in recent years due to various factors, including habitat loss, pesticide use, and disease. A better understanding of genome diversity in pollinator species, and how it has changed over time, will provide valuable insights into the factors driving these declines and inform future conservation efforts, in turn will benefiting both natural and farmed plant populations. To understand how pollinator genomes are changing, and whether there is a shared history of population change across different pollinating insect taxa, we need to a baseline to compare against. Fortunately, museum collections offer a unique opportunity to access DNA from historical pollinator specimens, which can be used to establish that baseline, and reveal changes in genome diversity. Here we will analyse DNA from modern and museum collections of pollinator insect species to understand the impacts of ongoing pollinator decline at the genome level. We will examine changes in diversity across species which are in decline, and others which are stable or expanding, to measure the impact of change in population size, structure and selection pressure. Our specific objectives are to: O1. Determine whether there are broad patterns of population structure in our target species, and whether those patterns have been stable over the past 100 years. This is important for determining management and conservation strategy for the species, and in any future effort to predict responses to land-use and climate change. O2. Determine the degree of genome diversity in our target species, and whether it has been stable over the past 100 years. These metrics are critical for establishing whether reduction in population size have led to inbreeding and reduced fitness or whether there is evidence for introgression from overseas populations. These metrics will also be used to assess the resilience of these species to novel selective forces in future. O3. Determine whether there is clear evidence of selection in our target species for loci associated with resistance to pesticides, pathogens, and changes in diet and metabolism. We can already identify candidate loci in the literature, and will extend this list as the project advances. These data will inform future management strategy by establishing the extent to which species have already adapted to changes in their environment, and at which loci. O4. Establish any clear patterns of genome diversity change in our target species and determine how these relate to known changes in land-use, climate, pesticide usage, and observation records. We will do this by compiling regional level data on these changes, and comparing the timing and rate of shifts in genome-data. This project has the potential to provide critical insights into the past and future response of pollinator insect species to recent environmental change. However, the potential findings go well beyond conservation biology or agriculture. Currently, we have very little genome data on insect populations beyond pest species, but these species provide fundamental ecosystem services across the globe. In addition, almost no genome analyses have been conducted on museum insect collections, meaning that this project has potential to advance the emerging field of collections genomics, using the vast numbers of museum specimens available to explore basic evolutionary processes over ecological timescales.