Phylogenetics of the Genus Omiodes
(Lepidoptera: Crambidae)

My main focus is the evolutionary history of a radiation of moths in the genus Omiodes. The genus Omiodes contains about 80 species worldwide, in both the neotropics and paleotropics. Hawai‘i is home to 23 endemic species, all of which likely descended from a single ancestor that colonized the islands some millions of years ago.

The Hawaiian species show a range of host specificities, ranging from generalists whose larvae feed on many types of native and non-native grasses, to specialists which feed only on a single species of native plant such as Dianella sandwicensis (ukiuki) . There is also some variation in degree of geographic endemism; many species are widespread and found on all the main Hawaiian Islands, while others are restricted to a single island.

One of the oddest things about the evolutionary history of these moths, and what inspired me to work on them, is that five species of endemic Hawaiian Omiodes have apparently evolved to specialize on the leaves of Polynesian cultivars of banana, a plant that was introduced into Hawai‘i within the past 1,500 years. It has been presumed that the divergence of these species from a palm-feeding ancestor was triggered by the introduction of banana, implying a very rapid rate of speciation, and presenting a rare opportunity to examine speciation or host-race formation.

Unfortunately, partly due to the impacts of non-native predators and parasitoids, many species of Omiodes, including four of the banana-feeding species, have been listed as extinct, and Hawaiian cultivars of banana are themselves threatened. However, we have successfully rediscovered several species of Omiodes formerly thought to be extinct, and I am hopeful that extant populations of banana-feeding species exist.

Disharmony of Hawaiian Insects

I also have a more general interest in insect lineages in the Hawaiian Islands, and the factors affecting both colonization and diversification. Because Hawai‘i is the most isolated land mass in the world, it is no easy task for an insect to arrive here on its own. Certain types of insects are more likely than others to reach the Hawaiian Islands and survive, and certain groups (not necessarily the same ones) are more likely than others to diversify once they've established.

This has led to a very disharmonic composition of the Hawaiian biota as compared to continental biota, with some groups extremely over-represented and other groups under-represented.

For example, within the order Lepidoptera, we have about 1,000 endemic species in Hawai'i, all presumably descended from about 58 colonizing species. Of these 1,000 species, only two are butterflies (superfamily Papilionoidea); thus a group that accounts for 13% of Lepidoptera species worldwide accounts for only 0.2% of Hawaiian Lepidoptera.

On the other end of the spectrum, the family Cosmopterigidae, which accounts for less than 1% of Lepidoptera species worldwide, includes 350 species in Hawai‘i, comprising more than a third of Hawaiian Lepidoptera. Similar examples can be found across the Hawaiian flora and fauna.

I am conducting formal analyses of the Hawaiian insect biota to identify groups that have had significantly higher or lower success at colonizing and diversifying than one would expect at random. I am also exploring factors that might be correlated with colonization and radiation success, such as body size, host specificity, and wing length.

My goal is to reconstruct the evolutionary history of this group using molecular markers, including the genes cytochrome oxidase I, wingless, and elongation factor 1-alpha. I will include in my analyses Omiodes species from elsewhere in the world, including New Guinea, Australia, and the neotropics. I hope to answer the following questions using molecular data:

- Are the Hawaiian species correctly placed in the genus Omiodes?

- How many ancestral Omiodes colonized the Hawaiian Islands?

- Where in the world did the colonizing ancestor(s) come from?

- How has host specialization evolved within the Hawaiian Omiodes?

- Is it possible that the banana-feeding species have diverged in the past 1,500 years?

Funding

My work at the University of Hawai‘i has primarily been supported by an NSF GK-12 teaching fellowship and an NSF Graduate Research Fellowship.

Haines, W. P. and G. A. Samuelson. (2006). The Eucalyptus snout beetle, Gonipterus scutellatus (Coleoptera: Curculionidae), recently established in the Hawaiian Islands. Bishop Museum Occasional Papers. 88 (Records of the Hawaii Biological Survey): 25-26. pdf

Rubinoff, D. and W. P. Haines. 2005. Web-spinning caterpillar stalks snails. Science. 309(5734): 575.

Haines, W. P. , J. Giffin and D. Foote. 2004. Rediscovery of five species of Omiodes Guenée (Lepidoptera: Crambidae) on Hawaii Island. Bishop Museum Occasional Papers. 79 (Records of the Hawaii Biological Survey): 45-49. pdf

Johnson, P. J., W. P. Haines and D. Foote. 2001. A new generic combination and Hawaiian Island record for Adelocera beardsleyi (Coleoptera: Elateridae). Bishop Museum Occasional Papers. 69 (Records of the Hawaii Biological Survey): 29-31.