Off to the Marquesas

There will be a dearth of blog postings for about four weeks, because tomorrow I am off to the Marquesas Islands for almost four weeks on an expedition with people from my lab and one from the Australian National Museum. Today the Australian Museum guy and I hiked the Three Coconuts Pass trail looking for drosophilids (fruit flies). There were a lot buzzing around mushrooms, rotting Tahitian chestnut (Inocarpus) fruit, and fallen flowers. Also we saw these cool-looking metallic green and pointed dolichopodid flies that rested on leaves. I learned how to identify a few genera I didn't know, and I found a new population of fairly large cheese trees I hadn't known about. I also got pretty wet and muddy. A good day in the field.

The Marquesas are one of the three great recent volcanic hotspot archipelagos on the Pacific Plate. The other two are the Society Islands (where I am now) and Hawai'i. The Marquesas are said to be the island group farthest from any continent in the world, halfway between Mexico and Australia. The fauna and flora of the Marquesas are therefore of considerable interest to evolutionary biology as a comparison to that of Hawai'i and the Societies. In a crude sense, the colonization of these different archipelagos by the same groups of organisms can be thought of as independent evolutionary experiments. In the case of cheese trees, there are 14 species in the Societies, only 3 in the Marquesas, and none in Hawai'i, so what has been going on in the Marquesas relative to the Societies is of great interest to me. (The diversity of cheesetree moths in these places, on the other hand, is virtually unknown.) One possibility is that the Marquesas were colonized much later than the Societies by the trees and their moths, and they've just had less time to diversify. Or there could be some aspect of the ecology or geology of the Marquesas that is less conducive to diversification. Or it could just be random. The Marquesas are also very interesting because two species of cheese tree have been reported to be hybridizing there; if this is true, it has implications for how these trees and moths have been co-diversifying.

So the Marquesas are fascinating, but they are also much harder to get to, and get around, than the Societies or Hawai'i. It's a three-hour plane flight from Tahiti to Nuku Hiva, and the Nuku Hiva airport is apparently a three or four-hour 4WD trip from the main town, on the other side of the island. Far fewer people live there, and the terrain is extremely rugged. North Marquesan and South Marquesan are also different languages from Tahitian, and are more closely related to Hawaiian. So it's a relief to be going with a group, including people who have already been there. We fly first to Nuku Hiva, then to Ua Pou, and then to Hiva Oa. While in Hiva Oa, we will try to get to Fatu Hiva, the southernmost island, which also lacks an airport. If I get any Internet access, I will try to post updates, but don't keep your fingers crossed!