Ecological and occurrence data for Melitaea

Genetic diversity provides the foundation for populations to adapt to environmental change and persist over time, yet the processes that shape it are not uniform across species or environments. We show that genetic diversity in Melitaea butterflies is shaped by interactions among biotic, environmental, and historical factors, rather than by universal drivers acting independently. In particular, the relationship between taxonomic diversity and genetic diversity changed with environmental context, revealing that biotic interactions can have contrasting effects across ecological settings. We also found substantial differences among species in their responses to the same predictors. These findings highlight the importance of considering species-specific responses, spatial scale, and ecological context when seeking to understand how evolutionary processes generate and maintain biodiversity.