A review of the endemic Hawaiian Drosophilidae and their host plants

The Hawaiian Drosophilidae is one of the best examples of rapid speciation in nature. Nearly 1,000 species of endemicdrosophilids have evolved in situ in Hawaii since a single colonist arrived over 25 million years ago. A number of mech-anisms, including ecological adaptation, sexual selection, and geographic isolation, have been proposed to explain theevolution of this hyperdiverse group of species. Here, we examine the known ecological associations of 326 species ofendemic Hawaiian Drosophilidae in light of the phylogenetic relationships of these species. Our analysis suggests thatthe long-accepted belief of strict ecological specialization in this group does not hold for all taxa. While many specieshave a primary host plant family, females will also oviposit on non-preferred host plant taxa. Host shifting is fairly com-mon in some groups, especially the grimshawi and modified mouthparts species groups of Drosophila, and the Scapto-myza subgenus Elmomyza. Associations with types of substrates (bark, leaves, flowers) are more evolutionarilyconserved than associations with host plant families. These data not only give us insight into the role ecology has playedin the evolution of this large group, but can help in making decisions about the management of rare and endangered hostplants and the insects that rely upon them for survival