Monday, December 10, 2007 - 10:05 AM

Molecular data challenge an apparent rapid speciation onto a non-native plant: Phylogenetics of Hawaiian moths in the genus Omiodes (Lepidoptera: Crambidae)

William P. Haines, and Daniel Rubinoff, University of Hawaii, Dept. of Plant and Environmental Protection Sciences, 3050 Maile Way, Gilmore 310, Honolulu, HI

The genus Omiodes Guenée includes a radiation of 23 species of endemic Hawaiian moths, as well as about 60 species widely dispersed elsewhere in the tropics. One complex of five Hawaiian Omiodes species has been reared only from the leaves of banana, introduced to Hawaii less than 1500 years ago. This complex was presumed to be the result of very recent, rapid speciation triggered by a shift from native palms onto banana. Using data from mitochondrial and nuclear genes (cytochrome oxidase I, wingless, elongation factor 1-alpha), we explored diversification patterns and rates among Omiodes from Hawaii and elsewhere in the Pacific and neotropics. We included 15 Hawaiian species in our analyses, including two banana-feeding species. Although the Hawaiian Omiodes seem to have diversified relatively rapidly after initial colonization of the islands, mitochondrial sequence data do not suggest rapid speciation within the banana-feeding complex. Instead, the banana-feeding species appear to have diverged on the scale of millions, and not thousands, of years ago, suggesting that banana is a secondary host for these species, and that they originally diversified on native hostplants that may now be rare or extinct. Our results support the monophyly of the Hawaiian Omiodes, but the genus as a whole appears paraphyletic with relation to several other spilomeline genera. A revision of this group is needed, and may eventually lead to the reassignment of the Hawaiian Omiodes to another genus.

Species 1: Lepidoptera Crambidae Omiodes blackburni (coconut leaf roller)
Species 2: Lepidoptera Crambidae Omiodes maia
Species 3: Lepidoptera Crambidae Omiodes musicola