Genetic structure of Prays fraxinella

Our aim was to use genetic data generated using ddRAD-seq to determine the population structure of an ash obligate micro-moth, Prays fraxinella (ash bud moth), and to assess its capacity for functional connectivity across fragmented patches of native broadleaf woodlands in different regions of the UK. In spring 2021 (April – May) we collected larvae of P. fraxinella that were feeding on shoots; we searched all accessible branches of ash trees exhaustively. Each larva was taken from a different tree to avoid sampling siblings. We reared them to adults in the lab (fresh ash leaves every 2 days) to confirm the species (as they are indistinguishable from Prays ruficeps as larvae) and once adults stored them in molecular grade ethanol. We found no evidence of genetic structuring at local (up to 44 km) spatial scales, and no evidence of inbreeding related to existing habitat fragmentation. At regional scales (up to 426 km) we found evidence of mixed ancestry and long-distance dispersal.