Lepidopteran phylogenetics : the largest phylogenetic tree of butterflies and moths sequenced to date

Sammanfattning

Phylogenetic trees are used to illustrate and study evolutionary relationships between organisms or genes and are created using gene sequences from taxa. Barcode reference trees are used for studying ecological and evolutionary patterns, for classifying taxa or for measuring phylogenetic diversity. Although well-known, we still have a lot to learn about the Lepidoptera order of insects. In this study, I first created a genus-level reference tree based on 24 lepidopteran superfamilies that was then expanded into a BOLD-species supertree of Lepidoptera. The reference tree was created using maximum likelihood in IQ-tree, and the BOLD tree was made by adding BOLD taxa to the backbone, using phylogenetic placement and online tree inference (OTI). The resulting reference tree contained 5331 genera from 25 superfamilies, and the BOLD tree contained 54738 taxa. The quality of the tree was checked by measuring grouping of sequences according to their taxonomy and measuring how well sequences grouped to their reference genera. The sequences grouped relatively well according to taxonomy, indicating a successful tree inference, and the sequences placed themselves near their reference taxon. Accumulation curves of phylogenetic diversity (PD) for each superfamily were also made and the maximum PD and PD completeness estimated. The PD completeness ranged around 40-60 % indicating that there is still a lot of phylogenetic diversity to be discovered. To conclude, this tree provides a new overview of the current understanding of the Lepidopteran diversity and can be used for further identification of Lepidopteran taxa.