Researchers Use Genomics and Citizen Science to Determine Migration History of Invasive Butterfly

September 11, 2019

Citizen scientists contributed to a genomic study of the Pieris rapae, a.k.a. small cabbage white butterfly, to determine its migration history. It is one of the world’s most abundant and destructive butterflies. Photo courtesy of Lauren Nichols.

Pieris rapae, commonly known as the small cabbage white butterfly, may be small and delicate to the eye, but producers of cruciferous vegetables such as cauliflower, broccoli, and cabbage know that it is one of the most destructive butterflies in the world. While much is known about the butterfly’s destructive nature, scientists just recently conducted the first study of its genetic diversity to reconstruct (maybe “uncover”) its history as an invasive pest.

The National Academy of Sciences published a study led by Sean F. Ryan, then a postdoctoral researcher in the University of Tennessee’s Department of Entomology and Plant Pathology, detailing the history of the small cabbage white butterfly including its origins and worldwide invasion. Ryan, currently with Exponent, Inc., and his research team relied on over 150 citizen scientists – people who voluntarily contribute to a scientific project but are not necessarily trained professionals within the field of study – from thirty-two countries to collect thousands of small cabbage white butterfly samples. The researchers, affiliated with institutions in the United States and Europe, conducted genetic analyses to better understand the butterfly’s genetic diversity, and determine its migration history over time. Think 23&Me but with butterflies.

The researchers showed that the small cabbage white butterfly originated in eastern Europe and has spread to all continents except South America and Antarctica. The butterfly’s historical migration patterns coincide with human migration and the developments of new trade routes and food sources for the larvae. Although each invasion into a new area or country led to significant loss of genetic diversity, the invasions were successful, hence the abundance of small cabbage white butterflies today.

Citizen science projects—those that enlist the help of the public in conducting
research—have been growing exponentially over the last decade, opening doors
to new scientific frontiers and expanding the limits of what was once feasible. The
relatively unique approach taken by Ryan et al. is that they asked the public to
help collect, and not just observe, these agricultural pests, and in so doing were
able to extract information recorded within the DNA of each individual butterfly,
that when aggregated told a story about the collective past of the small cabbage
white butterfly.

- DeWayne Shoemaker, Head and Professor,
UT Department of Entomology and Plant Pathology

The following researchers co-authored this study:

• Eric Lombaert (INRA, Université Côte d’Azur, CNRS, ISA, Sophia-Antipolis, France)
• Anne Espeset (Department of Biology, University of Nevada, Reno)
• Roger Vila (Institut de Biologia Evolutiva (CSIC-UPF), Barcelona, Spain)
• Gerard Talavera (Institut de Biologia Evolutiva (CSIC-UPF), Barcelona, Spain;
Department of Organismic and Evolutionary Biology and Museum of Comparative
Zoology, Harvard University)
• Vlad Dincă (Department of Ecology and Genetics, University of Oulu, Finland)
• Meredith M. Doellman (Department of Biological Sciences, University of Notre Dame)
• Mark A. Renshaw (Oceanic Institute, Hawai’i Pacific University)
• Matthew W. Eng (Department of Biological Sciences, University of Notre Dame)
• Emily A. Hornett (Department of Evolution, Ecology and Behaviour, University of
Liverpool, United Kingdom; Department of Vector Biology, Liverpool School of Tropical
Medicine, United Kingdom)
• Yiyuan Li (Department of Biological Sciences, University of Notre Dame)
• Michael E. Pfrender (Department of Biological Sciences, University of Notre Dame;
Environmental Change Initiative, University of Notre Dame)
• DeWayne Shoemaker (Department of Entomology and Plant Pathology, University of


The research team received the following support for this project:

• USDA National Institute of Food and Agriculture AFRI Postdoctoral Fellowship grant
• The National Science Foundation Graduate Research Fellowship Grant No. NSF-1447692
• Project CGL2016-76322-P (AEI/FEDER, UE)
• The MINECO programme IJCI-2016-29083
• The National Geographic Society (grant WW1-300R-18)
• Marie Curie Actions IO Fellowship no. 330136

Further Information:

Ryan, Sean F., et al. “Global Invasion History of the Agricultural Pest Butterfly Pieris Rapae Revealed with Genomics and Citizen Science.” Proceedings of the National Academy of Sciences, Sept. 2019, p. 201907492, doi:10.1073/pnas.1907492116.


Contact: DeWayne Shoemaker,

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