Drivers of moth phenology in England and Wales

Climate change has led to changes in the phenology of Lepidoptera species. While phenological shifts have been previously measured for moth species in England and Wales, the drivers of these shifts are not well known. Here, we use data from the National Moth Recording Scheme and the Garden Moth Scheme to investigate the drivers of phenology in 149 moth species over a 50 year period from 1970 to 2019. We investigate whether there have been phenological shifts in adult emergence using three phenology metrics: First Emergence (FE), Peak Emergence (PE), and Emergence Standard Deviation (ESD) in relation to life history traits and temperature. Overwintering stage had a significant impact on moth phenology, so we analysed species that spend the winter as eggs, larvae or pupae separately. Overall phenological changes were different depending on overwintering stage category and phenological measure, with the rate of phenological shifts increasing with later overwintering life stages in response to both temperature and year. The overwintering stage larva was the only one impacted by diet, with those that feed on woody hostplants emerging 17 days later than species with herbaceous hostplants. These results indicate that species that either overwinter in earlier life stages or have woody hostplants may be less adaptable to climate change, and thus should be the targets of conservation efforts.