Molecular Phylogeny, Revised Higher Classification, and Implications for Conservation of Endangered Hawaiian Leaf-Mining Moths (Lepidoptera: Gracillariidae: Philodoria)

The leaf-mining moth genus Philodoria Walsingham (Lepidoptera: Gracillariidae) is composed of 30 described species, all of which are endemic to the Hawaiian Islands. Philodoria is known to feed on 10 families of endemic Hawaiian host plants, with several species recorded only from threatened or endangered hosts. Beyond their dependence on these plants, little is known of their evolutionary history and conservation status. We constructed a molecular phylogeny of Philodoria to assess validity of its current subgeneric classification and to help guide future work on this threatened Hawaiian lineage. Mitochondrial and nuclear DNA sequences from three genes (CO1, CAD, EF-1 alpha) combining for a total of 2,041 base pairs, were collected from 11 Philodoria species, incorporating taxa from both currently recognized subgenera. These data were analyzed using both parsimony and model-based phylogenetic approaches. Contrary to the most recent systematic treatment of Philodoria, our results indicate strongly that the two currently recognized Philodoria subgenera are not monophyletic and that morphological characters used to classify them are homoplasious. Based on our robust results, we revised the higher classification of Philodoria: the subgenus Eophilodoria Zimmerman, 1978 is established as subjective junior synonym of Philodoria Walsingham, 1907. We also present new host plant and distribution data and discuss host range of Philodoria as it pertains to endangered Hawaiian plants.