BioProject

Here we demonstrate the power of the public to aid in collections-based research, where through an international citizen science project, Pieris Project, we were able to generate genetic evidence and combine it with historical records to uncover routes of invasion of the small cabbage white butterfly—Pieris rapae. We find that the spread of this butterfly across Eurasia occurred relatively recently (<3,000 years ago) and was later followed by a near linear series of introductions beginning in Europe. These invasions coincided with human migration, trade, and the diversification of the butterflies’ food plants. The success of this butterfly despite repeated losses in genetic diversity provides further evidence that species’ invasions may not always be impeded by loss of genetic diversity.