Comprehensive Lepidoptera Phylogenetic Sampling

Complete coverage of the lepidopteran families and superfamilies, many of which contain just a few, difficult-to-collect species, is beyond the reach of this initial study. Our more modest aim here was simply to represent a majority of the probable major lineages of Ditrysia. The distribution of our exemplars across the major clades of Minet [6 ] is shown in Additional file 1, which also lists families/superfamilies not sampled, to illustrate the extent of our coverage. Our sampling, which builds on a preliminary study of macrolepidopteran (especially bombycoid) relationships [14 (link)], is most dense in Macrolepidoptera (66 exemplars; 11 of 11 superfamilies) and non-macrolepidopteran Obtectomera (17 exemplars; 4 of 6 superfamilies), which together contain about 70% of ditrysian species diversity. Thirty species of non-obtectomeran Apoditrysia are included, representing eight of eleven superfamilies, and seven species of non-apoditrysian Ditrysia representing four of five superfamilies. One of the latter, Tineoidea (two species included), was used to root the tree, as tineoids are generally agreed to be the oldest superfamily of Ditrysia [1 ,6 ,15 ]. We sampled relatively extensively within a few larger superfamilies, both to get an adequate estimate of ancestral character states, and to further test the resolving power of our genes within superfamilies; our main focus, however, is among-superfamily relationships. Altogether our sample includes 27 of 33 superfamilies and 55 of 100 families of Ditrysia. The six superfamilies not represented each contain fewer than 100 species. The missing families are likewise mostly species poor, the main exceptions being Lycaenidae and several large families of Gelechioidea. Thus, the families represented in our study contain the great majority (>85%) of all species of Ditrysia. The classification system used (Additional file 1) follows the authorities in Kristensen [5 ], with exceptions as noted, including the following: in Pyraloidea we follow the more recent classification of Solis and Maes [16 ]; in Geometridae we update the classification following Hausmann [17 ], Holloway [18 ], Scoble [19 ] and Young [20 ].
Specimens for this study, obtained with the kind help of collectors around the world (see Acknowledgements) are stored in 100% ethanol at -85°C as part of the ATOLep collection at the University of Maryland (details at http://www.leptree.net/collection). DNA extraction used only the head and thorax for most species, leaving the rest of the body including the genitalia as a voucher (see Additional file 1). Wing voucher images for all adult exemplars are posted at http://www.leptree.net/voucher_image_list, and DNA 'barcodes' for nearly all specimens have been kindly generated by the All-Leps Barcode of Life project http://www.lepbarcoding.org/, allowing check of our identifications against the BOLD (Barcode of Life Data system) [21 (link)] reference library and facilitating future identification of specimens whose identity is still pending (i.e., species listed as 'sp.' or 'unidentified' in this report).