Repeated patterns of diversification in Lepidoptera?
Insights from Nymphalidae evolutionary history on the diversification of phytophagous insects
Welcome to the home page of the Nymphalidae Systematics Group at the Laboratory of Genetics, University of Turku. The group is headed by Niklas Wahlberg and our major goal is to contribute to the understanding of evolutionary processes that are involved in diversification of species. Our model group has for long been the family Nymphalidae, which has been of exceptional utility in developing both practical laboratory methods as well as insights into the processes leading to diversification. Our results have shown that the butterflies are older than previously thought and that there have been several periods during the history of the Earth that have strongly affected the diversification of Nymphalidae, such as the Cretaceous-Paleogene mass extinction event and the drying up of the planet during the Oligocene.
These results, along with results suggesting that similar patterns are found in the other butterfly families, have prompted us to expand our studies to other families of Lepidoptera. In particular we have been working on the noctuoid complex of families and Geometridae, but are also working in collaboration on other families. We have been able to utilize the primers developed for Nymphalidae across all of Lepidoptera, which allows us to rapidly generate large datasets for analysis. We are also currently developing new methods that take advantage of Next Generation Sequencing technologies, that allow us to generate much larger datasets than earlier. We thus intend to test new and exciting hypotheses about the factors driving diversification in Lepidoptera, from the comparatively species poor nonditrysians to the large megadiverse families of Ditrysia.
We continue to work on Nymphalidae, especially in collaboration with other researchers focussing on particular subgroups within the family. Our database now has multiple gene sequences for about 2000 species of Nymphalidae (up to 11 gene regions per species), making it possible to study the details of diversification processes in almost any taxon of the family. We are particularly interested in the subfamily Satyrinae, as it is the most species-rich subfamily of Nymphalidae and shows intriguing patterns of diversification. It has also proven to be a challenging subfamily to study, with problems ranging from species definitions to methodological problems associated with potential rapid radiations.
The NSG uses mainly molecular methods in its work. In order to document our sources of DNA, we have a policy of putting up images of our voucher specimens (when available) on the internet. To access these images follow the Voucher database link above. We also aim to link our voucher images with their respective DNA sequences on public databases through GenBank's LinkOut service.
Our work is highly collaborative and we collaborate with many people around the world. Our work is not restricted to Lepidoptera, we work also on other insect orders, viruses, plants, and even the evolutionary history of languages. We continue to explore other systems that help us understand how evolution has shaped the world we live in.