Niche Separation in a Pair of Homosequential Drosophila Species from the Island of Hawaii

Abstract

Two exceedingly closely related species of Drosophila coexist in a sparsely vegetated xeric area on the island of Hawaii. Of the two major trees in the area, Myoporum sandwicense alone appears to support the existence of both species. Whereas both feed as adults on Myoporum flux, D. silvarentis oviposits only on fluxes which wet the trunk well above the ground surface. Drosophila heedi larvae are found exclusively in caked soil moistened by flux dripping from above. Implications of this type of niche separation for the evolution of sibling or near-sibling species are discussed.