Ecology and Evolution of Drosophila ambochila, A Rare Picture-Winged Species Endemic to the Wai'anae Range of O'ahu, Hawaiian Islands

The rare O'ahu picture-winged fly Drosophila ambochila Hardy & Kaneshiro is endemic to two windward ravines in the Wai'anae Mountains that harbor its host plant. Drosophila ambochila is an ecological specialist that breeds on Pisonia stems and trunks in an intermediate stage of decay. By providing field-collected females with suitable substrate material, we have been able to observe the oviposition behavior of this species in the laboratory and obtain F 1 larvae. In nature, females oviposit each batch of mature eggs ("'4050) in a single cluster, by repeatedly inserting their long ovipositor into the same crack or beetle hole in the decaying Pisonia bark. Ovipositor, ovary, and egg morphology are characteristic of bark-breeding Hawaiian Drosophila, but SEM studies revealed a distinctive chorionic ultrastructure for the eggs of this species. Larval salivary chromosome analyses indicated that the O'ahu D. ambochila is most closely related to D. alsophila from the island of Hawai'i and have helped to resolve the phylogenetic relationships among six of the nine species belonging to the vesciseta subgroup of the glabriapex species group

Origin, adaptive radiation and diversification of the Hawaiian lobeliads (Asterales: Campanulaceae)

The endemic Hawaiian lobeliads are exceptionally species rich and exhibit striking diversity in habitat, growth form, pollination biology and seed dispersal, but their origins and pattern of diversification remain shrouded in mystery. Up to five independent colonizations have been proposed based on morphological differences among extant taxa. We present a molecular phylogeny showing that the Hawaiian lobeliads are the product of one immigration event; that they are the largest plant clade on any single oceanic island or archipelago; that their ancestor arrived roughly 13 Myr ago; and that this ancestor was most likely woody, wind-dispersed, bird-pollinated, and adapted to open habitats at mid-elevations. Invasion of closed tropical forests is associated with evolution of fleshy fruits. Limited dispersal of such fruits in wet-forest understoreys appears to have accelerated speciation and led to a series of parallel adaptive radiations in Cyanea, with most species restricted to single islands. Consistency of Cyanea diversity across all tall islands except Hawai `i suggests that diversification of Cyanea saturates in less than 1.5 Myr. Lobeliad diversity appears to reflect a hierarchical adaptive radiation in habitat, then elevation and flower-tube length, and provides important insights into the pattern and tempo of diversification in a species-rich clade of tropical plants