DNA barcoding and the renaissance of taxonomy
- Office of the Under Secretary for Science, Smithsonian Institution, Washington, DC 20013-7012
How limited (or not) is the dietary range of an animal species? How does that host specificity plot across major lineages of organisms? How does that affect the structure of ecological communities? These are major questions in ecology, especially for invertebrates, where they have major implications for academic questions, such as how many species of insects there are, and practical applications in fields such as biological control (1). A multidisciplinary team representing field ecology, molecular genetics, and morphological taxonomy presents data in this issue of PNAS (2) that challenge our traditional assumptions of parasite diversity and host specificity in a system of tachinid flies that parasitize moth and butterfly caterpillars in Costa Rica (Fig. 1).
Puparium (dark amber) of Patelloa xanthuraDHJ02 (DHJPAR0003513), a truly generalist tachinid fly confirmed as such by ref. 2. The fly larva emerged from the newly killed caterpillar of Parides iphidamas(Papilionidae) a few hours before this image was taken (caterpillar voucher 05-SRNP-4432, August 19, 2005, Area de Conservacion Guanacaste, Costa Rica). (Photo courtesy of D. H. Janzen.)
The work of Smith et al. (2) is a display of integrated taxonomy, demonstrating how DNA barcoding is a valuable addition to the taxonomic tool box. It integrates ecological, genetic, and morphological data to provide a robust analysis and also tests the primary genetic data (mitochondrial COI sequences) against other sequences (nuclear 28S and ITS1). This analysis is rooted in 29 years of inventory of ≈400,000 wild-caught caterpillars in northwestern Costa Rica, the largest data set ever assembled on the basic biology of caterpillars, their host plants, and their parasites in a wildland setting. In their study, Smith et al. investigated 2,134 flies belonging to what appeared to be the 16 most generalist of the reared tachinid morphospecies. The combined evidence indicated that most of …
*E-mail: millers{at}si.edu
