Acknowledgements:
We thank C. Couchoux for advice on the genotyping work, S. Ikonen for rearing the insects, and S. Ojanen and many students from the University of Helsinki, who conducted the annual survey and collected the samples over the years. We are grateful to I. Hanski and P. Seppä for their interest in and constructive discussions on the study. This work was supported by the Academy of Finland (grant #266021 to AD, and #255553 to SvN). Diversity, Equality and Inclusion statement: The authors highly value equity, diversity and inclusion in science. We acknowledge the international character of our team, which significantly contributed to the completion and quality of the study. It includes researchers from different countries, backgrounds and career stages. Authors are from France, India, Hungary and USA. Three co-authors are female and one is male. We cite a large body of studies from a potentially male-biased author-list. We wish to address these DEI shortcomings in future work.